+publisher:"Colorado State University" +contributor:("Ham, Jay")

Colorado State University

1. Gupta, Vatsal. Methods to detect and analyse volatile organic carbons using low cost real-time sensors.

Degree: MS(M.S.), Civil and Environmental Engineering, 2019, Colorado State University

URL: http://hdl.handle.net/10217/199733

► VOCs are ubiquitous and can be found not only as vapors in the air but also as soil gas and dissolved in ground water. Vapor… (more)

Subjects/Keywords: fracking; soil gas sensors; volatile organic carbon; oil and gas; data analysis; trend analysis

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APA (6^th Edition):

Gupta, V. (2019). Methods to detect and analyse volatile organic carbons using low cost real-time sensors. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/199733

Chicago Manual of Style (16^th Edition):

Gupta, Vatsal. “Methods to detect and analyse volatile organic carbons using low cost real-time sensors.” 2019. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/199733.

MLA Handbook (7^th Edition):

Gupta, Vatsal. “Methods to detect and analyse volatile organic carbons using low cost real-time sensors.” 2019. Web. 26 Feb 2021.

Vancouver:

Gupta V. Methods to detect and analyse volatile organic carbons using low cost real-time sensors. [Internet] [Masters thesis]. Colorado State University; 2019. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/199733.

Council of Science Editors:

Gupta V. Methods to detect and analyse volatile organic carbons using low cost real-time sensors. [Masters Thesis]. Colorado State University; 2019. Available from: http://hdl.handle.net/10217/199733

Colorado State University

2. Hogan, Wesley W. Internet of things monitoring of the oxidation reduction potential in an oleophilic bio-barrier.

Degree: MS(M.S.), Civil and Environmental Engineering, 2020, Colorado State University

URL: http://hdl.handle.net/10217/212070

► Petroleum hydrocarbons discharged to surface water at a groundwater-surface water interface (GSI) resulting in violations of the Clean Water Act often spark costly cleanup efforts.… (more)

▼ Petroleum hydrocarbons discharged to surface water at a groundwater-surface water interface (GSI) resulting in violations of the Clean Water Act often spark costly cleanup efforts. The oleophilic bio-barrier (OBB) has been shown to be effective in catching and retaining oils via an oleophilic (oil-loving) geocomposite and facilitating biodegradation through cyclic delivery of oxygen and nutrients via tidally driven water level fluctuations. Conventional resistive (e.g., geomembrane) or absorptive-only (e.g., organoclay) barriers for oil at GSIs limit oxygen diffusion into underlying sediments and are susceptible to overloading and bypass. Conversely, OBBs are designed to function as sustainable oil-degrading bioreactors. For an OBB to be effective, the barrier must maintain aerobic conditions created by tidally driven oxygen delivery. Oxidation reduction potential (ORP) sensors were installed within an OBB in the northeastern US with an internet of things (IoT) monitoring system to either confirm the sustained oxidizing conditions within the OBB, or to detect a problem within the OBB and trigger additional remedial action. Real-time ORP data revealed consistently aerobic oxidation-reduction (redox) conditions within the OBB with periods of slightly less oxidized redox conditions in response to precipitation. By interpreting ORP data in real time, we were able to verify that the OBB maintained the oxidizing conditions critical to the barrier functioning as an effective aerobic bioreactor to degrade potentially-sheen generating oils at GSIs. In addition, alternative oleophilic materials were tested to increase the range of candidate materials that may function as the oleophilic component of an OBB. Materials tested included thin black (232 g/m2), thin white (244 g/m2), medium black (380 g/m2), and thick black (1055 g/m2) geotextiles, as well as a coconut fiber coir mat. Finally, a model was developed to estimate the required sorptive capacity of the oleophilic component of an OBB based on site-specific conditions, which can be used to inform OBB design. Advisors/Committee Members: Scalia, Joseph (advisor), Sale, Thomas (advisor), Ham, Jay (committee member).

Subjects/Keywords: IoT; oil; petroleum; OBB; biodegradation; ORP

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APA (6^th Edition):

Hogan, W. W. (2020). Internet of things monitoring of the oxidation reduction potential in an oleophilic bio-barrier. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/212070

Chicago Manual of Style (16^th Edition):

Hogan, Wesley W. “Internet of things monitoring of the oxidation reduction potential in an oleophilic bio-barrier.” 2020. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/212070.

MLA Handbook (7^th Edition):

Hogan, Wesley W. “Internet of things monitoring of the oxidation reduction potential in an oleophilic bio-barrier.” 2020. Web. 26 Feb 2021.

Vancouver:

Hogan WW. Internet of things monitoring of the oxidation reduction potential in an oleophilic bio-barrier. [Internet] [Masters thesis]. Colorado State University; 2020. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/212070.

Council of Science Editors:

Hogan WW. Internet of things monitoring of the oxidation reduction potential in an oleophilic bio-barrier. [Masters Thesis]. Colorado State University; 2020. Available from: http://hdl.handle.net/10217/212070

Colorado State University

3. Ferrie, Zach. Real-time visualization of advective groundwater flow.

Degree: MS(M.S.), Civil and Environmental Engineering, 2020, Colorado State University

URL: http://hdl.handle.net/10217/208481

► As the portfolio of sites with subsurface contamination matures, long-term monitoring is becoming the primary factor governing costs for managing historical releases of contaminants to… (more)

▼ As the portfolio of sites with subsurface contamination matures, long-term monitoring is becoming the primary factor governing costs for managing historical releases of contaminants to soil and groundwater. Hydraulic gradients are the primary factor driving the velocity and direction in which subsurface contaminants move, making them an important parameter to resolve. Current best practices for tracking groundwater flow include either collecting head data by hand or deploying pressure transducers and periodically returning to manually download the data. Unfortunately, cost restraints and infrequent data collection and processing are not conducive to timely responses to adverse conditions. In this study, two low-cost cellular connected data acquisition systems are developed which allow for collection and analysis of head data in real-time. Using planar regressions of three head values, automated algorithms are used to estimate the direction and rate of groundwater flow on an hourly basis. Another novel addition is the integration of real-time alerts. By automating various alerts, site managers can be notified when conditions reach a pre-determined threshold. Automated alerts allow for swift action to be taken to adverse conditions and can lead to greater safety for the public while saving sites from costly mistakes. Following Devlin and McElwee (2007), uncertainty in groundwater flow direction is a function of measurement error, spacing between wells, and local hydraulic gradients. By using these sources of uncertainty to create synthetic datasets, algorithms are used to estimate the likely range of a groundwater flow path. The effects of pressure transducer drift (i.e. increasing measurement error over time) and their effect on uncertainty are also explored. Results from this study show that as long as the drift is similar in magnitude and direction for all pressure transducers, the effect on the uncertainty in the model is negligible. Additionally, the effects of uncertainty in anisotropy on deviation from the estimated flow path are considered by way of synthetic datasets, which is novel to this research. The results of this research reveal that the effects of anisotropy uncertainty on groundwater flow direction and seepage velocity are also tied to well spacing. Comparisons of the effects of measurement error vs anisotropy uncertainty are compared for four field sites. Results show that the magnitudes of each source of error are site specific and that the effects of measurement error are not always greater than the effects of anisotropy uncertainty and vice versa. Lastly, the seepage velocities are expressed by way of a color scheme common across sites. This novel addition allows for easy visualization of seepage velocities across time and space. Overall, the vision from this research is that real-time, continuous collection and analysis of head data can proceed as outlined in this Thesis. In the future manually collected and interpreted head data need to be compared to the automated analyses described in this… Advisors/Committee Members: Sale, Thomas (advisor), Blotevogel, Jens (advisor), Ham, Jay (committee member).

Subjects/Keywords: engineering; groundwater; real-time; environmental; contaminant; hydrology

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APA (6^th Edition):

Ferrie, Z. (2020). Real-time visualization of advective groundwater flow. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/208481

Chicago Manual of Style (16^th Edition):

Ferrie, Zach. “Real-time visualization of advective groundwater flow.” 2020. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/208481.

MLA Handbook (7^th Edition):

Ferrie, Zach. “Real-time visualization of advective groundwater flow.” 2020. Web. 26 Feb 2021.

Vancouver:

Ferrie Z. Real-time visualization of advective groundwater flow. [Internet] [Masters thesis]. Colorado State University; 2020. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/208481.

Council of Science Editors:

Ferrie Z. Real-time visualization of advective groundwater flow. [Masters Thesis]. Colorado State University; 2020. Available from: http://hdl.handle.net/10217/208481

Colorado State University

4. Wells, Bradley. Validation of emission rate estimation methods, The.

Degree: MS(M.S.), Atmospheric Science, 2015, Colorado State University

URL: http://hdl.handle.net/10217/166977

► Oil and natural gas production throughout the United States has been dramatically increasing in recent years, due in large part to hydraulic fracturing processes and… (more)

▼ Oil and natural gas production throughout the United States has been dramatically increasing in recent years, due in large part to hydraulic fracturing processes and horizontal drilling techniques that allow for extraction from unconventional wells. The rise in well drilling and completion activities raises concern over potential air quality impacts on nearby communities. Methane, other volatile organic compounds (VOCs), and nitrogen oxides (NOₓ) may be emitted into the atmosphere during well development and production activities. Methane is a greenhouse gas, VOCs and NOₓ act as ozone precursors, and some VOCs are classified as air toxics. For these reasons, there is a need to accurately quantify the rate of emissions of these gases into the atmosphere from oil and gas development and production. One such emission rate estimation technique is the tracer ratio method (TRM). The TRM requires access to a well site and involves the release of a passive tracer gas as close to the source of emissions as possible. This known emission rate is multiplied by the ratio of the downwind concentrations of emission gas to the tracer gas (both in excess of background) to derive an estimate of the emission gas emission rate. Another technique, recently developed by the Environment Protection Agency, utilizes a simplified point source Gaussian plume (PSG) dispersion model. This approach requires only one mobile downwind measurement location for both concentration and meteorological measurements, without the need for site access; it does not require a tracer gas. In order to evaluate the effectiveness of these techniques, a series of experiments were conducted at Christman airfield in Fort Collins, Colorado. These experiments involved releasing both acetylene, as a tracer gas, and methane (to simulate an emission source) at controlled flow rates to compare the predicted emission rate of methane to its actual emission rate. A vehicle equipped with a PICARRO methane and acetylene analyzer traversed or remained stationary within the gas plume to provide real-time concentration measurements of both gases. A 3-D sonic anemometer was used to characterize local meteorological conditions. The TRM is evaluated using both a mobile transect and a stationary approach. There is an overall positive bias in both cases. Our best results are obtained when sources are co-located during a stationary analysis and changes in background methane concentrations are determined and corrected. In these cases the mean bias is +9% with σ=22% (standard deviation about the mean bias). The separation of tracer and emission gas sources in the mobile transect analysis is the largest cause for uncertainty. The mean bias when sources are separated is +83% (σ=99%), as opposed to transect analyses of co-located sources which have a mean bias of +33% (σ=31%). The PSG technique, which involves a 20 minute stationary analysis, contains more inconsistent results compared to the stationary approach performed by the TRM (mean bias of methane emission rate prediction… Advisors/Committee Members: Collett, Jeffrey L. (advisor), Pierce, Jeffrey (advisor), Ham, Jay (committee member).

Subjects/Keywords: Gaussian plume; emission rates; tracer ratio method

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APA (6^th Edition):

Wells, B. (2015). Validation of emission rate estimation methods, The. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/166977

Chicago Manual of Style (16^th Edition):

Wells, Bradley. “Validation of emission rate estimation methods, The.” 2015. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/166977.

MLA Handbook (7^th Edition):

Wells, Bradley. “Validation of emission rate estimation methods, The.” 2015. Web. 26 Feb 2021.

Vancouver:

Wells B. Validation of emission rate estimation methods, The. [Internet] [Masters thesis]. Colorado State University; 2015. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/166977.

Council of Science Editors:

Wells B. Validation of emission rate estimation methods, The. [Masters Thesis]. Colorado State University; 2015. Available from: http://hdl.handle.net/10217/166977

Colorado State University

5. Duncan, Caroline R. Patterns of dust-enhanced absorbed energy and shifts in melt timing for snow of southwestern Colorado.

Degree: MS(M.S.), Ecosystem Science and Sustainability, 2020, Colorado State University

URL: http://hdl.handle.net/10217/211991

► Deposited dust layers reduce the surface albedo of snow and accelerate melt by this change to the snowpack energy balance. Senator Beck Study Basin in… (more)

Subjects/Keywords: melt; dust; snow

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APA (6^th Edition):

Duncan, C. R. (2020). Patterns of dust-enhanced absorbed energy and shifts in melt timing for snow of southwestern Colorado. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/211991

Chicago Manual of Style (16^th Edition):

Duncan, Caroline R. “Patterns of dust-enhanced absorbed energy and shifts in melt timing for snow of southwestern Colorado.” 2020. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/211991.

MLA Handbook (7^th Edition):

Duncan, Caroline R. “Patterns of dust-enhanced absorbed energy and shifts in melt timing for snow of southwestern Colorado.” 2020. Web. 26 Feb 2021.

Vancouver:

Duncan CR. Patterns of dust-enhanced absorbed energy and shifts in melt timing for snow of southwestern Colorado. [Internet] [Masters thesis]. Colorado State University; 2020. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/211991.

Council of Science Editors:

Duncan CR. Patterns of dust-enhanced absorbed energy and shifts in melt timing for snow of southwestern Colorado. [Masters Thesis]. Colorado State University; 2020. Available from: http://hdl.handle.net/10217/211991

Colorado State University

6. Grant, Leah Danielle. Relative influence of aerosols and the environment on organized tropical and midlatitude deep convection, The.

Degree: MS(M.S.), Atmospheric Science, 2014, Colorado State University

URL: http://hdl.handle.net/10217/82553

► In this two-part study, the relative impacts of aerosols and the environment on organized deep convection, including tropical sea-breeze convection and midlatitude supercellular and multicellular… (more)

▼ In this two-part study, the relative impacts of aerosols and the environment on organized deep convection, including tropical sea-breeze convection and midlatitude supercellular and multicellular deep convection, are investigated within idealized cloud-resolving modeling simulations using the Regional Atmospheric Modeling System (RAMS). Part one explores aerosol-cloud-land surface interactions within tropical deep convection organized along a sea breeze front. The idealized RAMS domain setup is representative of the coastal Cameroon rainforest in equatorial Africa. In order to assess the potential sensitivity of sea-breeze convection to increasing anthropogenic activity and deforestation occurring in such regions, 27 total simulations are performed in which combinations of enhanced aerosol concentrations, reduced surface roughness length, and reduced soil moisture are included. Both enhanced aerosols and reduced soil moisture are found to individually reduce the precipitation due to reductions in downwelling shortwave radiation and surface latent heat fluxes, respectively, while perturbations to the roughness length do not have a large impact on the precipitation. The largest soil moisture perturbations dominate the precipitation changes due to reduced low-level moisture available to the convection, but if the soil moisture perturbation is moderate, synergistic interactions between soil moisture and aerosols enhance the sea breeze precipitation. This is found to result from evening convection that forms ahead of the sea breeze only when both effects are present. Interactions between the resulting gust fronts and the sea breeze front locally enhance convergence and therefore the rainfall. Part two of this study investigates the relative roles of midlevel dryness and aerosols on supercellular and multicellular convective morphology. A common storm-splitting situation is simulated wherein the right-moving storm becomes a dominant supercell and the left-moving storm evolves into a multicellular cluster. The right-mover, which is a classic (CL) supercell in the control simulation, becomes a low-precipitation (LP) supercell with increasing dryness aloft. Different midlevel hail growth mechanisms are found to dominate in the CL and LPs that assist in explaining their varying surface precipitation distributions. Although the CL and LP supercells are dynamically similar, their microphysical structure differs due to the strong control that midlevel dryness exerts on supercell morphology; aerosols have little impact on the supercellular structure. On the other hand, while midlevel dryness also dominates the changes to the multicellular convection, aerosols influence the precipitation through feedbacks to the cold pool strength and subsequent dynamical forcing. Overall, aerosol impacts are largest for the most weakly organized convection (tropical sea breeze convection) and smallest for strongly dynamic convection (supercells). Additionally, aerosol impacts are modulated by environmental influences, most notably soil moisture… Advisors/Committee Members: van den Heever, Susan C. (advisor), Johnson, Richard H. (committee member), Ham, Jay M. (committee member).

Subjects/Keywords: aerosol-cloud-land surface interactions; hail growth; mesoscale modeling; multicells; sea breeze; supercells

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APA (6^th Edition):

Grant, L. D. (2014). Relative influence of aerosols and the environment on organized tropical and midlatitude deep convection, The. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/82553

Chicago Manual of Style (16^th Edition):

Grant, Leah Danielle. “Relative influence of aerosols and the environment on organized tropical and midlatitude deep convection, The.” 2014. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/82553.

MLA Handbook (7^th Edition):

Grant, Leah Danielle. “Relative influence of aerosols and the environment on organized tropical and midlatitude deep convection, The.” 2014. Web. 26 Feb 2021.

Vancouver:

Grant LD. Relative influence of aerosols and the environment on organized tropical and midlatitude deep convection, The. [Internet] [Masters thesis]. Colorado State University; 2014. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/82553.

Council of Science Editors:

Grant LD. Relative influence of aerosols and the environment on organized tropical and midlatitude deep convection, The. [Masters Thesis]. Colorado State University; 2014. Available from: http://hdl.handle.net/10217/82553

Colorado State University

7. Westover, Elin C. Effect of crude protein withdrawal and the use of oscillated crude protein concentration on feedlot performance, carcass merit, and ammonia emissions from the pen surface of feedlot steers, The.

Degree: MS(M.S.), Animal Sciences, 2011, Colorado State University

URL: http://hdl.handle.net/10217/47422

► Six hundred crossbred steers (BW, 329.7 ± 7.58 kg) were used to investigate the effect of CP withdrawal and the use of oscillating CP concentrations… (more)

▼ Six hundred crossbred steers (BW, 329.7 ± 7.58 kg) were used to investigate the effect of CP withdrawal and the use of oscillating CP concentrations on feedlot performance, digestibility, carcass merit, and ammonia emissions from the pen surface of yearling steers. Steers were randomly assigned to one of the following treatments: HCP [Control, 13.5% CP, 3.5% CP equivalents (CPE)]); OCP (11.62% CP, 1.5% CPE fed Wednesday, Thursday, and Sunday and the HCP diet fed Monday, Tuesday, Friday, and Saturday); EICP (12.56% CP from d28 to slaughter, 2.53% CPE); ELCP (11.62% CP from d28 to slaughter, 1.55% CPE); LICP (HCP throughout with the ICP diet fed the last 27d); and LLCP (HCP throughout with the LCP diet fed the last 27d). Urea was used to modify dietary CP concentrations. Steers were housed in 9-steer pens (n=48) or 7-steer mass balance pens (n=24). Steers were weighed and ultrasound images and fecal grab samples were taken 3 or 4 times (depending upon replicate) throughout the trial. Feed samples, fecal grab samples, and mass balance pen surface samples were analyzed for DM, AIA, N, and P. Soil samples were obtained from the mass balance pens for treatments HCP, OCP, and ELCP and tested for total ammonia volatilization. Steers were harvested on d 149 or d 175 and camera carcass data was collected. Although initial BW differences between treatments were not significant (P > 0.18), initial BW was a significant (P < 0.10) source of variation describing interim and final BW and was therefore included in the data analysis as a covariate. There were no treatment differences for BW (P > 0.23) throughout the study. Average daily gain for each time period or for the entire study was not affected by treatment (P > 0.26). There was a difference (P < 0.05) in DMI between treatments from d 106 to slaughter (HCP > ELCP, LLCP, and LICP), and overall DMI tended (P < 0.11) to be affected by treatment (HCP > ELCP and LLCP). Treatment differences for G: F and net energy recovery were not significant (P > 0.30). There were no significant (P > 0.21) effects of dietary treatment on carcass merit. Treatment differences for DM digestibility calculated from DMI and fecal output as estimated by AIA, were not significant (P > 0.37) and averaged 85.7, 83.6, 84.2, and 83.0% for the HCP, OCP, EICP, and ELCP diets respectively. Treatment differences for CP digestibility, calculated from N intake and fecal N, were significant (P < 0.001) and averaged 83.3, 76.6, 78.8, and 74.3% for the HCP, OCP, EICP, and ELCP diets respectively (HCP > OCP, EICP, and ELCP). Nitrogen intake was significantly (P < 0.0001) affected by treatment and averaged 183, 172, 167, and 155 g per head daily for the HCP, OCP, EICP, and ELCP treatments respectively. Differences between treatments for amount of fecal N (P > 0.18) and calculated amount of retained N (P > 0.42) were not significant. Urinary N, calculated as N intake minus fecal and retained N, excretion was reduced (P < 0.0001) as N intake decreased with treatment averaging 128, 111, 108, and 94 g per steer daily for… Advisors/Committee Members: Wagner, John J. (advisor), Engle, Terry E. (advisor), Ham, Jay M. (committee member).

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APA (6^th Edition):

Westover, E. C. (2011). Effect of crude protein withdrawal and the use of oscillated crude protein concentration on feedlot performance, carcass merit, and ammonia emissions from the pen surface of feedlot steers, The. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/47422

Chicago Manual of Style (16^th Edition):

Westover, Elin C. “Effect of crude protein withdrawal and the use of oscillated crude protein concentration on feedlot performance, carcass merit, and ammonia emissions from the pen surface of feedlot steers, The.” 2011. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/47422.

MLA Handbook (7^th Edition):

Westover, Elin C. “Effect of crude protein withdrawal and the use of oscillated crude protein concentration on feedlot performance, carcass merit, and ammonia emissions from the pen surface of feedlot steers, The.” 2011. Web. 26 Feb 2021.

Vancouver:

Westover EC. Effect of crude protein withdrawal and the use of oscillated crude protein concentration on feedlot performance, carcass merit, and ammonia emissions from the pen surface of feedlot steers, The. [Internet] [Masters thesis]. Colorado State University; 2011. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/47422.

Council of Science Editors:

Westover EC. Effect of crude protein withdrawal and the use of oscillated crude protein concentration on feedlot performance, carcass merit, and ammonia emissions from the pen surface of feedlot steers, The. [Masters Thesis]. Colorado State University; 2011. Available from: http://hdl.handle.net/10217/47422

Colorado State University

8. Mkhwanazi, Mcebisi. Developing a modified SEBAL algorithm that is responsive to advection by using limited weather data.

Degree: PhD, Civil and Environmental Engineering, 2014, Colorado State University

URL: http://hdl.handle.net/10217/83792

► The use of Remote Sensing ET algorithms in water management, especially for agricultural purposes is increasing, and there are more models being introduced. The Surface… (more)

▼ The use of Remote Sensing ET algorithms in water management, especially for agricultural purposes is increasing, and there are more models being introduced. The Surface Energy Balance Algorithm for Land (SEBAL) and its variant, Mapping Evapotranspiration with Internalized Calibration (METRIC) are some of the models that are being widely used. While SEBAL has several advantages over other RS models, including that it does not require prior knowledge of soil, crop and other ground details, it has the downside of underestimating evapotranspiration (ET) on days when there is advection, which may be in most cases in arid and semi-arid areas. METRIC, however has been modified to be able to account for advection, but in doing so it requires hourly weather data. In most developing countries, while accurate estimates of ET are required, the weather data necessary to use METRIC may not be available. This research therefore was meant to develop a modified version of SEBAL that would require minimal weather data that may be available in these areas, and still estimate ET accurately. The data that were used to develop this model were minimum and maximum temperatures, wind data, preferably the run of wind in the afternoon, and wet bulb temperature. These were used to quantify the advected energy that would increase ET in the field. This was a two-step process; the first was developing the model for standard conditions, which was described as a healthy cover of alfalfa, 40-60 cm tall and not short of water. Under standard conditions, when estimated ET using modified SEBAL was compared with lysimeter-measured ET, the modified SEBAL model had a Mean Bias Error (MBE) of 2.2 % compared to -17.1 % from the original SEBAL. The Root Mean Square Error (RMSE) was lower for the modified SEBAL model at 10.9 % compared to 25.1 % for the original SEBAL. The modified SEBAL model, developed on an alfalfa field in Rocky Ford, was then tested on other crops; beans and wheat. It was also tested on well-irrigated corn and also corn under deficit irrigation. The modified SEBAL model performed fairly well in wheat and beans, just slightly underestimating ET, and it performed well with irrigated corn. However, modified SEBAL, similar to the original SEBAL and also METRIC, could not accurately estimate ET for drier conditions or at early stages of plant growth. Advisors/Committee Members: Chávez, José (advisor), Andales, Allan (committee member), Ham, Jay (committee member), Trout, Thomas (committee member).

Subjects/Keywords: modified; evapotranspiration; SEBAL; energy fluxes; evaporative fraction

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APA (6^th Edition):

Mkhwanazi, M. (2014). Developing a modified SEBAL algorithm that is responsive to advection by using limited weather data. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/83792

Chicago Manual of Style (16^th Edition):

Mkhwanazi, Mcebisi. “Developing a modified SEBAL algorithm that is responsive to advection by using limited weather data.” 2014. Doctoral Dissertation, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/83792.

MLA Handbook (7^th Edition):

Mkhwanazi, Mcebisi. “Developing a modified SEBAL algorithm that is responsive to advection by using limited weather data.” 2014. Web. 26 Feb 2021.

Vancouver:

Mkhwanazi M. Developing a modified SEBAL algorithm that is responsive to advection by using limited weather data. [Internet] [Doctoral dissertation]. Colorado State University; 2014. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/83792.

Council of Science Editors:

Mkhwanazi M. Developing a modified SEBAL algorithm that is responsive to advection by using limited weather data. [Doctoral Dissertation]. Colorado State University; 2014. Available from: http://hdl.handle.net/10217/83792

Colorado State University

9. Subedi, Abhinaya. Modeling a variable surface resistance (rs) for alfalfa and assessing the ASCE rs performance in the reference evapotranspiration equation.

Degree: PhD, Civil and Environmental Engineering, 2016, Colorado State University

URL: http://hdl.handle.net/10217/178812

► Accurate quantification of crop water requirement is necessary for proper irrigation water management. The knowledge of actual crop evapotranspiration (ETc) is important and is necessary… (more)

▼ Accurate quantification of crop water requirement is necessary for proper irrigation water management. The knowledge of actual crop evapotranspiration (ETc) is important and is necessary for estimating irrigation water requirements. The most common procedure of obtaining actual crop evapotranspiration (ETc) is by first calculating the reference crop evapotranspiration (ETr) and then multiplying it with the appropriate crop coefficients (Kc). If the surface resistance (rs) of a particular crop can be modeled, then ETc can be directly calculated without using Kc. The overall objectives of this dissertation were to model surface resistance for alfalfa reference crop and to find an effective value of the surface resistance of alfalfa in the ASCE Standardized Reference ET equation. It has been found that using a single Kc curve for different climatic conditions can lead to significant error in estimating ETc. Hence it is important to find appropriate Kc for different crops for local climatic condition. Lysimeters are generally used to determine the values of Kc, as lysimetry is considered a reliable method of quantifying the ET losses from a control volume. This study found that using lysimeter ET data to obtain Kc can be problematic especially when the field is heterogeneous. In order to develop Kc for various crops, it is recommended to use some years of reliable data with uniform healthy and unstressed crop surface conditions both inside and outside the lysimeter. This study was focused on to develop a model for surface resistance (rs) of alfalfa in order to calculate alfalfa ETc in a one-step approach without the need for Kc values. Surface resistance was estimated by inverting the aerodynamic equation using ET measured from lysimeter and sensible heat flux (H) measured from large aperture scintillometer (LAS). This observed rs showed a very good correlation with leaf area index (LAI) and crop height (hc). The alfalfa rs was then modeled as a function of LAI and hc (which is referred to as rs(LAI) and rs(hc) respectively). Then these modeled rs s were incorporated into the Penman Monteith (PM) equation to estimate alfalfa hourly ET, which performed very well when compared with the measured hourly lysimeter ET. The conventional alfalfa rs, developed by Allen et al. (1989) was found to underestimate rs significantly especially when the crop height was short (less than 25 cm). It was found that ET_conventional_rs was not applicable to estimate alfalfa ET when the crop height was less than 25 cm. The modeled rs(LAI) and rs(hc) are constant throughout the day, but in reality, rs changes throughout the day. Hence hourly variable rs was also developed based on aerodynamic resistance (ra), canopy temperature (Tc) and vapor pressure deficit (VPD). It was found that PM equation incorporating the hourly variable rs improved the alfalfa ET estimation when compared with the conventional rs approach. ASCE-EWRI Standardized Reference ET for tall reference crop was found to underestimate measured ET by about 10 per cent. The… Advisors/Committee Members: Chávez, José (advisor), Andales, Allan (advisor), Ramirez, Jorge (committee member), Ham, Jay (committee member).

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APA (6^th Edition):

Subedi, A. (2016). Modeling a variable surface resistance (rs) for alfalfa and assessing the ASCE rs performance in the reference evapotranspiration equation. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/178812

Chicago Manual of Style (16^th Edition):

Subedi, Abhinaya. “Modeling a variable surface resistance (rs) for alfalfa and assessing the ASCE rs performance in the reference evapotranspiration equation.” 2016. Doctoral Dissertation, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/178812.

MLA Handbook (7^th Edition):

Subedi, Abhinaya. “Modeling a variable surface resistance (rs) for alfalfa and assessing the ASCE rs performance in the reference evapotranspiration equation.” 2016. Web. 26 Feb 2021.

Vancouver:

Subedi A. Modeling a variable surface resistance (rs) for alfalfa and assessing the ASCE rs performance in the reference evapotranspiration equation. [Internet] [Doctoral dissertation]. Colorado State University; 2016. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/178812.

Council of Science Editors:

Subedi A. Modeling a variable surface resistance (rs) for alfalfa and assessing the ASCE rs performance in the reference evapotranspiration equation. [Doctoral Dissertation]. Colorado State University; 2016. Available from: http://hdl.handle.net/10217/178812

Colorado State University

10. Joy, Stuart L. Evaluation of analytical footprint models and energy balance closure methods over cotton in Texas panhandle.

Degree: MS(M.S.), Civil and Environmental Engineering, 2011, Colorado State University

URL: http://hdl.handle.net/10217/70781

► Eddy covariance (EC) systems are being used to measure sensible heat (H) and latent heat (LE) fluxes in order to determine crop water use or… (more)

▼ Eddy covariance (EC) systems are being used to measure sensible heat (H) and latent heat (LE) fluxes in order to determine crop water use or evapotranspiration (ET). However, EC systems tend to systematically underestimate H and LE fluxes; thus, a lack of energy balance closure. The reliability of EC measurements depends on meeting certain meteorological assumptions; the most important of such are a horizontal homogeneity, stationarity, and non-advective conditions. Over heterogeneous surfaces the spatial context of the measurement must be known in order to properly interpret the magnitude of the heat flux measurement results. Over the past two decades there has been a proliferation of `heat flux source area' (i.e., footprint) modeling studies but only a few that explore the accuracy of models over heterogeneous agricultural land. A composite ET estimate was created by using the estimated footprint weights for an EC system in the upwind corner of four fields and separate ET estimates from each of these fields. Three analytical footprint models were evaluated by comparing the composite ET to the measured ET. All three models performed consistently with an average MBE of about -0.03 mm h-1 (-4.4%) and RMSE of 0.09 mm h-1 (10.9%). The same three footprint models were then used to adjust measured ET to account for the fraction of the footprint that extended beyond the field of interest. The effectiveness of the footprint adjustment was determined by comparing adjusted ET estimates with lysimetric ET measurements from within the same field. This correction decreased the absolute hourly ET MBE by 8% and the RMSE by 1%. The energy balance is rarely closed with the EC method and therefore the energy balance was closed by adjusting the H and LE heat fluxes by first assuming the H was measured accurately and applying the entire residual to the LE (LEC) heat flux and secondly by assuming the Bowen ratio (BRC) was measured accurately and adjusting both H and LE while conserving the BR. The application of energy balance closure to uncorrected EC heat fluxes showed better agreement between EC and lysimeter ET. There was not a significant difference between the BRC and LEC methods when applied to uncorrected heat fluxes. The analytical footprint models developed by Schuepp et al. (1990), Hsieh et al. (2000), and Kormann and Meixner (2001) all gave a reliable estimate of the footprint for heterogeneous agricultural land under highly advective conditions. Care should be taken when using the EC system to measure ET early in the growth stage of a crop when the surface is smooth because the footprint will extend farther upwind. Correcting the EC heat fluxes for coordinate rotation, density, spectral attenuation, and sonic temperature heat flux and then applying the proposed correction considering the footprint resulted in the most accurate estimate of hourly EC based ET with a MBE of 0.01 mm h-1 (0.6 to 1.5%) and RMSE of 0.10 to 0.11 mm h-1 (10.6 to 11.66%). Advisors/Committee Members: Chávez, José Luis (advisor), Ham, Jay (committee member), Andales, Allan A. (committee member).

Subjects/Keywords: cotton; footprint; evapotranspiration; energy balance closure; eddy covariance

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APA (6^th Edition):

Joy, S. L. (2011). Evaluation of analytical footprint models and energy balance closure methods over cotton in Texas panhandle. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/70781

Chicago Manual of Style (16^th Edition):

Joy, Stuart L. “Evaluation of analytical footprint models and energy balance closure methods over cotton in Texas panhandle.” 2011. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/70781.

MLA Handbook (7^th Edition):

Joy, Stuart L. “Evaluation of analytical footprint models and energy balance closure methods over cotton in Texas panhandle.” 2011. Web. 26 Feb 2021.

Vancouver:

Joy SL. Evaluation of analytical footprint models and energy balance closure methods over cotton in Texas panhandle. [Internet] [Masters thesis]. Colorado State University; 2011. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/70781.

Council of Science Editors:

Joy SL. Evaluation of analytical footprint models and energy balance closure methods over cotton in Texas panhandle. [Masters Thesis]. Colorado State University; 2011. Available from: http://hdl.handle.net/10217/70781

Colorado State University

11. Kappen, Maria M. Decreasing nitrogen for volatilization in beef feedlot cattle.

Degree: MS(M.S.), Animal Sciences, 2012, Colorado State University

URL: http://hdl.handle.net/10217/67882

► The effects of ractopamine hydrochloride (RAC) and a steroidal implant (IMP), on whole body N metabolism were evaluated in 24 Hereford x Angus steers (BW… (more)

▼ The effects of ractopamine hydrochloride (RAC) and a steroidal implant (IMP), on whole body N metabolism were evaluated in 24 Hereford x Angus steers (BW 554.4 ± 26.8 kg). The experimental design was a completely randomized block design with a 2 x 2 factorial arrangement of treatments. Factors included: 1) RAC (0.0 or 400 mg×steer-1×d-1) and 2) IMP (0.0 or 200 mg trenbolone acetate and 28 mg of estradiol benzoate). Steers were housed in individual pens and allowed ad libitum access to feed and water throughout the experiment. Steers were acclimated to the metabolism barn by bringing in, tying and currying for 12 d before the initiation of the experiment. Once cattle had been implanted for 48 d and had received RAC for 21 d, a nutrient balance study was conducted for 6 d. An IMP x RAC interaction tended (P < 0.09) to exist for DMI. Implanted steers receiving RAC tended to have lower DMI compared to non-IMP steers receiving RAC as well as IMP steers not receiving RAC. N intake (P > 0.11) and fecal N (P > 0.18) were not different due to treatment, yet numerically reflected the trend noted for DMI. Urinary N excretion was decreased by feeding RAC (P < 0.01). There tended (P < 0.08) to be an IMP x RAC interaction for urinary N excretion. Implanted steers receiving RAC tended to have less urinary N than steers receiving an implant only. Similarly, urine urea N excretion was decreased by RAC treatment (P < 0.02) and excretion tended to be decreased in steers that had also received IMP (IMP x RAC interaction; P < 0.07). Overall N retention was not affected by treatment (P > 0.14). These results indicate that urinary N excretion can be reduced by incorporating RAC according to labeled usage during the final phase of the finishing period. However, more studies will be required to elucidate the potential interactions of RAC with implant status and types of implants. Advisors/Committee Members: Archibeque, Shawn L. (advisor), Engle, Terry E. (committee member), Ham, Jay M. (committee member).

Subjects/Keywords: ractopamine hydrochloride; estradiol benzoate; nitrogen balance; trenbolone acetate; urinary nitrogen; urinary urea nitrogen

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APA (6^th Edition):

Kappen, M. M. (2012). Decreasing nitrogen for volatilization in beef feedlot cattle. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/67882

Chicago Manual of Style (16^th Edition):

Kappen, Maria M. “Decreasing nitrogen for volatilization in beef feedlot cattle.” 2012. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/67882.

MLA Handbook (7^th Edition):

Kappen, Maria M. “Decreasing nitrogen for volatilization in beef feedlot cattle.” 2012. Web. 26 Feb 2021.

Vancouver:

Kappen MM. Decreasing nitrogen for volatilization in beef feedlot cattle. [Internet] [Masters thesis]. Colorado State University; 2012. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/67882.

Council of Science Editors:

Kappen MM. Decreasing nitrogen for volatilization in beef feedlot cattle. [Masters Thesis]. Colorado State University; 2012. Available from: http://hdl.handle.net/10217/67882

12. Kimbrough, Hal Reuben. Optimal sensor placement for sewer capacity risk management.

Degree: PhD, Systems Engineering, 2019, Colorado State University

URL: http://hdl.handle.net/10217/195315

► Complex linear assets, such as those found in transportation and utilities, are vital to economies, and in some cases, to public health. Wastewater collection systems… (more)

▼ Complex linear assets, such as those found in transportation and utilities, are vital to economies, and in some cases, to public health. Wastewater collection systems in the United States are vital to both. Yet effective approaches to remediating failures in these systems remains an unresolved shortfall for system operators. This shortfall is evident in the estimated 850 billion gallons of untreated sewage that escapes combined sewer pipes each year (US EPA 2004a) and the estimated 40,000 sanitary sewer overflows and 400,000 backups of untreated sewage into basements (US EPA 2001). Failures in wastewater collection systems can be prevented if they can be detected in time to apply intervention strategies such as pipe maintenance, repair, or rehabilitation. This is the essence of a risk management process. The International Council on Systems Engineering recommends that risks be prioritized as a function of severity and occurrence and that criteria be established for acceptable and unacceptable risks (INCOSE 2007). A significant impediment to applying generally accepted risk models to wastewater collection systems is the difficulty of quantifying risk likelihoods. These difficulties stem from the size and complexity of the systems, the lack of data and statistics characterizing the distribution of risk, the high cost of evaluating even a small number of components, and the lack of methods to quantify risk. This research investigates new methods to assess risk likelihood of failure through a novel approach to placement of sensors in wastewater collection systems. The hypothesis is that iterative movement of water level sensors, directed by a specialized metaheuristic search technique, can improve the efficiency of discovering locations of unacceptable risk. An agent-based simulation is constructed to validate the performance of this technique along with testing its sensitivity to varying environments. The results demonstrated that a multi-phase search strategy, with a varying number of sensors deployed in each phase, could efficiently discover locations of unacceptable risk that could be managed via a perpetual monitoring, analysis, and remediation process. A number of promising well-defined future research opportunities also emerged from the performance of this research. Advisors/Committee Members: Duff, William (advisor), Grigg, Neil (advisor), Labadie, John (committee member), Ham, Jay (committee member).

Subjects/Keywords: FMEA; risk management; wastewater; metaheuristics; agent-based models; sensor placement

10 more images…

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APA (6^th Edition):

Kimbrough, H. R. (2019). Optimal sensor placement for sewer capacity risk management. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/195315

Chicago Manual of Style (16^th Edition):

Kimbrough, Hal Reuben. “Optimal sensor placement for sewer capacity risk management.” 2019. Doctoral Dissertation, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/195315.

MLA Handbook (7^th Edition):

Kimbrough, Hal Reuben. “Optimal sensor placement for sewer capacity risk management.” 2019. Web. 26 Feb 2021.

Vancouver:

Kimbrough HR. Optimal sensor placement for sewer capacity risk management. [Internet] [Doctoral dissertation]. Colorado State University; 2019. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/195315.

Council of Science Editors:

Kimbrough HR. Optimal sensor placement for sewer capacity risk management. [Doctoral Dissertation]. Colorado State University; 2019. Available from: http://hdl.handle.net/10217/195315

Colorado State University

13. Schiferl, Luke D. Investigation of ammonia and inorganic particulate matter in California during the CalNex campaign, An.

Degree: MS(M.S.), Atmospheric Science, 2012, Colorado State University

URL: http://hdl.handle.net/10217/75114

► Over the last century, the rise of industrial agriculture has greatly increased the emission of ammonia (NH3) from livestock waste and synthetic crop fertilizers to… (more)

▼ Over the last century, the rise of industrial agriculture has greatly increased the emission of ammonia (NH3) from livestock waste and synthetic crop fertilizers to the atmosphere. Ammonium (NH4+) aerosol, which can be formed through the neutralization of atmospheric acids by NH3, is a key component of particulate matter (PM) in the atmosphere. PM causes negative human health effects and reduces visibility, and transport and deposition of excess NH3 can cause environmental degradation. Airborne observations of gas precursors and inorganic aerosol taken during the CalNex campaign in May and June 2010 are used in this study to investigate the role of NH3 in PM formation in California and test the representation of the key processes relevant to this chemical system in the GEOS-Chem chemical transport model. Evaluation of the 0.5° x 0.667° horizontal resolution nested model with observations shows a large underestimation (5.4 ppb median bias in the lowest 1 km) of NH3 in the Central Valley. This NH3 underestimation is lower in the area surrounding Los Angeles (LA), only 1.4 ppb. Sulfur dioxide (SO2) is also underestimated in both regions, while nitric acid (HNO3) shows little bias. Near-surface simulated inorganic PM is under-predicted by 1.28 µg sm-3 in the LA region and over-predicted in the Valley by 0.27 µg sm-3. Investigation of model sensitivity to the processes of gas-particle partitioning, wet deposition, dry deposition and emissions reveal that emissions have the largest potential for correction of model deficiencies. Increases to anthropogenic livestock NH3 emissions by a factor of 5 and anthropogenic SO2 emissions in the Valley by factors from 3 - 10 eliminates the bias in the simulation of gases in both regions and PM near LA, where under-prediction of nitrate (NO3-) is reduced from 0.64 µg sm-3 to 0.12 µg sm-3 in the lowest 1 km. An increase in NH3 emissions in the LA region is critical to capturing ammonium nitrate (NH4NO3) formation down-wind of the city core. Using this modified emissions simulation, seasonal PM differences in the two regions and the export of excess NH3 out of the Valley are explored. Mean June simulated PM concentration in the lowest 1 km is 3.48 µg sm-3 near LA (38% NO3- and 39% SO42-, by mass) and 1.98 µg sm-3 in the Valley (44% NO3- and 32% SO42-, by mass). These simulated PM concentrations are 2 times greater in the Valley in December than in June, when NH4NO3 formation is favored by colder temperatures. However, LA simulated PM concentration falls by 53% in December compared to June, likely due to lower winter NH3 emissions. Both the model and IASI satellite observations indicate that large amounts of excess NH3 are transported from the Valley to southeastern California in the summertime which may negatively affect ecosystems in this area. Advisors/Committee Members: Heald, Colette L. (advisor), Collett, Jeffrey L. (committee member), Ham, Jay M. (committee member).

Subjects/Keywords: CalNex; inorganic particulate matter; GEOS-Chem; ammonia; California

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APA (6^th Edition):

Schiferl, L. D. (2012). Investigation of ammonia and inorganic particulate matter in California during the CalNex campaign, An. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/75114

Chicago Manual of Style (16^th Edition):

Schiferl, Luke D. “Investigation of ammonia and inorganic particulate matter in California during the CalNex campaign, An.” 2012. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/75114.

MLA Handbook (7^th Edition):

Schiferl, Luke D. “Investigation of ammonia and inorganic particulate matter in California during the CalNex campaign, An.” 2012. Web. 26 Feb 2021.

Vancouver:

Schiferl LD. Investigation of ammonia and inorganic particulate matter in California during the CalNex campaign, An. [Internet] [Masters thesis]. Colorado State University; 2012. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/75114.

Council of Science Editors:

Schiferl LD. Investigation of ammonia and inorganic particulate matter in California during the CalNex campaign, An. [Masters Thesis]. Colorado State University; 2012. Available from: http://hdl.handle.net/10217/75114

Colorado State University

14. Warner, Crystal M. Management strategies for improved production practices to maximize efficiency associated with livestock production.

Degree: MS(M.S.), Animal Sciences, 2014, Colorado State University

URL: http://hdl.handle.net/10217/82667

► With the ever-increasing world population of over 7 billion and subsequent increase in urbanization, it is crucial for the livestock sector of agriculture to move… (more)

▼ With the ever-increasing world population of over 7 billion and subsequent increase in urbanization, it is crucial for the livestock sector of agriculture to move in the direction of sustainability. Appropriate changes in production practices ensure adequate production with fewer resources to meet the needs of the consumer. Multiple improvements within various management categories are essential to increase animal efficiency and economic gain, improved utilization of natural resources and reduce resulting environmental impacts. The National Air Quality Site Assessment Tool (NAQSAT), originally launched in 2010, provides its users the ability to qualitatively assess how effectively producers are mitigating harmful air emissions in site-specific beef, dairy, swine, broiler chicken, laying hen and turkey production facilities. The air emissions deemed to be of the greatest concern were odor, particulate matter (PM), ammonia (NH3), hydrogen sulfide (H2S), methane (CH4) and Volatile Organic Compounds (VOCs). Eight management categories are considered: animal housing, diet, manure handling, storage and application practices, mortality and road management. The tool enables users to run hypothetical scenarios to identify potential unintended consequences of management modification prior to making costly changes. The NAQSAT has since then been reviewed and updated by experts according to the most up-to-date knowledge and research to create version 2.0. The tool has expanded to include the horse species and air emission nitrous oxide (N2O). Following the implementation of the tool, users are directed to potentially applicable NRCS practices pertinent to their management goals within a given management category/emission of concern. Ideally this will guide users to reformed practices for continued sustainability in today's production environment. In order to accommodate this movement towards sustainability, diet modifications to the typical feedlot diet have been explored; 126 corn fed cross-bred steer calves (initial BW 529.5kg ± 10.7) were supplemented a rumen bypass fat during the last 60 days of the finishing period to evaluate its effects on feedlot performance, carcass characteristics and intramuscular fatty acid composition. Steers were blocked by initial, BW 9 head/pen (n = 7 pens / treatment), at the South Eastern Colorado Research Center (SECRC) in Lamar, CO. Pens were randomly assigned one of two treatment groups: 1) a control diet consisting of a regular corn based finishing ration (CON) and 2) rumen bypass fat treatment consisting of the control diet + Megalac-R/head/day (BF). Diets were formulated to be isocaloric and isonitrogenous. Animals were fed twice daily at 110% of the previous daily ad libitum intake. Feed bunks were cleaned and orts were collected weekly. Dry matter content was analyzed and diet samples were collected weekly for proximate analysis. Individual live weights were recorded and blood samples were collected on d -54, -10, 27 and 60 and 61. Feedlot performance and carcass characteristics were… Advisors/Committee Members: Archibeque, Shawn L. (advisor), Han, Hyungchul (committee member), Ham, Jay M. (committee member).

Subjects/Keywords: air quality; sustainability; rumen bypass fat; management practices; biohydrogenation

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APA (6^th Edition):

Warner, C. M. (2014). Management strategies for improved production practices to maximize efficiency associated with livestock production. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/82667

Chicago Manual of Style (16^th Edition):

Warner, Crystal M. “Management strategies for improved production practices to maximize efficiency associated with livestock production.” 2014. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/82667.

MLA Handbook (7^th Edition):

Warner, Crystal M. “Management strategies for improved production practices to maximize efficiency associated with livestock production.” 2014. Web. 26 Feb 2021.

Vancouver:

Warner CM. Management strategies for improved production practices to maximize efficiency associated with livestock production. [Internet] [Masters thesis]. Colorado State University; 2014. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/82667.

Council of Science Editors:

Warner CM. Management strategies for improved production practices to maximize efficiency associated with livestock production. [Masters Thesis]. Colorado State University; 2014. Available from: http://hdl.handle.net/10217/82667

Colorado State University

15. Piña, Aaron J. Transport of pollutants from eastern Colorado into the Rocky Mountains via upslope winds.

Degree: MS(M.S.), Atmospheric Science, 2013, Colorado State University

URL: http://hdl.handle.net/10217/81055

► The confluence of mountain meteorology and major pollution sources come together to transport pollutants across the Front Range, especially nitrogen species (NH3, NH4+, orgN, NO3-,… (more)

Subjects/Keywords: atmospheric nitrogen deposition; convective transport; mountain meteorology; nitrogen-loading; upslope winds; Rocky Mountains

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APA (6^th Edition):

Piña, A. J. (2013). Transport of pollutants from eastern Colorado into the Rocky Mountains via upslope winds. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/81055

Chicago Manual of Style (16^th Edition):

Piña, Aaron J. “Transport of pollutants from eastern Colorado into the Rocky Mountains via upslope winds.” 2013. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/81055.

MLA Handbook (7^th Edition):

Piña, Aaron J. “Transport of pollutants from eastern Colorado into the Rocky Mountains via upslope winds.” 2013. Web. 26 Feb 2021.

Vancouver:

Piña AJ. Transport of pollutants from eastern Colorado into the Rocky Mountains via upslope winds. [Internet] [Masters thesis]. Colorado State University; 2013. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/81055.

Council of Science Editors:

Piña AJ. Transport of pollutants from eastern Colorado into the Rocky Mountains via upslope winds. [Masters Thesis]. Colorado State University; 2013. Available from: http://hdl.handle.net/10217/81055

Colorado State University

16. MacDonald, Landan Patrick. Estimating emission rates of volatile organic compounds from oil and natural gas operations in the Piceance Basin.

Degree: MS(M.S.), Atmospheric Science, 2015, Colorado State University

URL: http://hdl.handle.net/10217/170281

► Oil and natural gas production has been steadily increasing in Colorado for the past 10 years. Garfield County is partially located above the natural gas… (more)

▼ Oil and natural gas production has been steadily increasing in Colorado for the past 10 years. Garfield County is partially located above the natural gas rich Piceance Basin. Horizontal drilling techniques provide increased access to subsurface gas deposits while hydraulic fracturing is employed to increase the permeability of the tight gas formations by pumping pressurized fluids into the ground to allow more cost-effective oil and gas extraction. Once fractured, the fluid is allowed to flow back to the surface to be captured before the well is considered producing. Our team conducted field measurements from 2013 to 2015 in Garfield County to determine emission rates of methane, hazardous air pollutants, and ozone precursors at 18 oil and gas operations. Drilling and well completion operations were targeted because they are understudied relative to production. We estimate the emission rates of methane and 58 additional VOCs (focusing on benzene, toluene, and ethane) for three common operations. We found benzene had mean emission rates of 0.72, 0.23, and 0.055 g/s for drilling, hydraulic fracturing, and flowback operations respectively. We calculated mean methane emission rates of 6.2, 29, and 64 g/s for drilling, hydraulic fracturing, and flowback operations respectively. We use the estimated methane emission rates from drilling and well completion operations to compare to typical well lifetime emissions during a 30 year production phase and find that drilling and well completion operations may be contributing from 0.1 to 10% of total well pad emissions. These results are based on a limited sampling size (18 sites) and limited overall measurement time (4.25 hours of total measurement time included in results). It is possible we did not perform measurements for long enough periods of time at enough sites. This study is beginning to fill the information gap by focusing on drilling and well completion operations. AERMOD is an atmospheric dispersion model used for new source apportionment. We compared our measured concentration fields to AERMOD predicted concentration fields by replicating fieldwork locations and conditions. Meteorological conditions were taken from an on-site meteorological station for use in the dispersion model. Comparing to the measurements, we found there was a low log-mean bias (-0.007) with a large amount of scatter (r = 0.0007). Additionally, we use AERMOD and data from the NCEP North American Regional Reanalysis database to predict the distribution of concentrations experienced throughout for various meteorological conditions in Garfield County at various distances surrounding oil and gas wells. We normalized these predicted concentration fields by emission rate and created cumulative distribution functions. Advisors/Committee Members: Pierce, Jeffrey R. (advisor), Collett, Jeffrey L. (advisor), Ham, Jay M. (committee member).

Subjects/Keywords: Colorado; emission rates; Garfield County; methane; natural gas; oil

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APA (6^th Edition):

MacDonald, L. P. (2015). Estimating emission rates of volatile organic compounds from oil and natural gas operations in the Piceance Basin. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/170281

Chicago Manual of Style (16^th Edition):

MacDonald, Landan Patrick. “Estimating emission rates of volatile organic compounds from oil and natural gas operations in the Piceance Basin.” 2015. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/170281.

MLA Handbook (7^th Edition):

MacDonald, Landan Patrick. “Estimating emission rates of volatile organic compounds from oil and natural gas operations in the Piceance Basin.” 2015. Web. 26 Feb 2021.

Vancouver:

MacDonald LP. Estimating emission rates of volatile organic compounds from oil and natural gas operations in the Piceance Basin. [Internet] [Masters thesis]. Colorado State University; 2015. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/170281.

Council of Science Editors:

MacDonald LP. Estimating emission rates of volatile organic compounds from oil and natural gas operations in the Piceance Basin. [Masters Thesis]. Colorado State University; 2015. Available from: http://hdl.handle.net/10217/170281

17. Schnarr, Cassandra. Crop residue: a hero's journey from biomass to soil carbon in eastern Colorado dryland crop rotation systems.

Degree: MS(M.S.), Soil and Crop Sciences, 2019, Colorado State University

URL: http://hdl.handle.net/10217/195370

► Crop residues play a vital role in reducing the potential for wind erosion of agricultural soils in arid and semi-arid regions. The residues act via… (more)

▼ Crop residues play a vital role in reducing the potential for wind erosion of agricultural soils in arid and semi-arid regions. The residues act via three modes: reducing wind speed, acting as a physical impediment to wind reaching the soil surface, and as an organic matter input to spur aggregation and aggregate stability. The interactions of crop residues, crop rotation systems, and wind erosion factors were studied at three long-term agricultural research sites along an evapotranspiration gradient near Sterling, Stratton, and Walsh, Colorado. The sites have a 30-year history of dryland, no-till management, and are divided into different cropping system intensities that vary in the frequency of summer fallow periods in the rotation. Crop rotations studied here include wheat (Triticum aestivum)-fallow, wheat-corn (Zea mays) – fallow, and continuously cropped plots with small grains and forage crops including foxtail millet (Setaria varidis) and forage sorghum (Sorghum bicolor). Forage crop and wheat residues were tracked over two growing seasons (2015 and 2016) to estimate the length of time before soil surface cover fell below a 30% threshold and to create models for residue persistence. Decomposition Days (DD), a calculation that factors in temperature and rainfall to estimate cumulative conditions that favor decomposition, was used to normalize time scales following harvest across sites and years. Wheat residue covered 82% of the soil surface following harvest and summer forage crops covered 56%. Wheat persisted longer, taking 62.5 DD to fall to the 30% cover threshold, forage crop residue remained above the threshold for 16.6 DD. The decline of forage crop residue cover followed an exponential decay model. Wheat residue surface cover had a longer, slower decline and fit a quadratic decay model. Wheat stem heights were taller following harvest and heights declined at a similar or faster rate than forage crops. To assess rotation legacy impacts on soil erodibility, soils were sampled in May 2015 and tested for dry aggregate size distribution, dry aggregate stability, and carbon distribution by size classes and between cropping intensities. No differences were found in the amount of erodible aggregate size fraction (<0.84mm) by cropping system intensity. The site with the highest amount of clay in the soil displayed a significant difference in aggregate stability by crop rotation, with wheat-fallow rotations having stability of 2.96 ln J/Kg and continuously cropped systems having 2.80 ln J/Kg. Carbon distribution did not differ by crop rotation but did differ by size class at the site with the highest potential evapotranspiration and lowest clay content where the largest aggregates contained the highest proportion of carbon. Every phase (i.e., rotation year) of each of the crop rotation systems were represented each year. There was a significant difference in mean erodible fraction and aggregate stability by cropping phase at the time of sampling at the site with the highest clay content. Taken together, the crop… Advisors/Committee Members: Schipanski, Meagan (advisor), Ham, Jay (committee member), Conant, Richard (committee member), Tatarko, John (committee member).

Subjects/Keywords: crop residue; dry aggregate stability; wind erosion; crop rotation system; aggregate size distribution; soil surface cover

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APA (6^th Edition):

Schnarr, C. (2019). Crop residue: a hero's journey from biomass to soil carbon in eastern Colorado dryland crop rotation systems. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/195370

Chicago Manual of Style (16^th Edition):

Schnarr, Cassandra. “Crop residue: a hero's journey from biomass to soil carbon in eastern Colorado dryland crop rotation systems.” 2019. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/195370.

MLA Handbook (7^th Edition):

Schnarr, Cassandra. “Crop residue: a hero's journey from biomass to soil carbon in eastern Colorado dryland crop rotation systems.” 2019. Web. 26 Feb 2021.

Vancouver:

Schnarr C. Crop residue: a hero's journey from biomass to soil carbon in eastern Colorado dryland crop rotation systems. [Internet] [Masters thesis]. Colorado State University; 2019. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/195370.

Council of Science Editors:

Schnarr C. Crop residue: a hero's journey from biomass to soil carbon in eastern Colorado dryland crop rotation systems. [Masters Thesis]. Colorado State University; 2019. Available from: http://hdl.handle.net/10217/195370

Colorado State University

18. Levin, Ezra JT. Remote continental aerosol characteristics in the Rocky Mountains of Colorado and Wyoming.

Degree: PhD, Atmospheric Science, 2013, Colorado State University

URL: http://hdl.handle.net/10217/78833

► The Rocky Mountains of Colorado and Wyoming enjoy some of the cleanest air in the United States, with few local sources of particulate matter or… (more)

▼ The Rocky Mountains of Colorado and Wyoming enjoy some of the cleanest air in the United States, with few local sources of particulate matter or its precursors apart from fire emissions, windblown dust, and biogenic emissions. However, anthropogenic influences are also present with sources as diverse as the populated Front Range, large isolated power plants, agricultural emissions, and more recently emissions from increased oil and gas exploration and production. While long-term data exist on the bulk composition of background fine particulate matter at remote sites in the region, few long-term observations exist of aerosol size distributions, number concentrations and size resolved composition, although these characteristics are closely tied to important water resource issues through the potential aerosol impacts on clouds and precipitation. Recent modeling work suggests sensitivity of precipitation-producing systems to the availability of aerosols capable of serving as cloud condensation nuclei (CCN); however, model inputs for these aerosols are not well constrained due to the scarcity of data. In this work I present aerosol number and volume concentrations, size distributions, chemical composition and hygroscopicity measurements from long-term field campaigns. I also explore the volatility of organic material from biomass burning and the potential impacts on aerosol loading. Relevant aerosol observations were obtained in several long-term field studies: the Rocky Mountain Atmospheric Nitrogen and Sulfur study (RoMANS, Colorado), the Grand Tetons Reactive Nitrogen Deposition Study (GrandTReNDS, Wyoming) and as part of the Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen project (BEACHON, Colorado). Average number concentrations (0.04 < Dp < 20 μm) measured during the field studies ranged between 1000 - 2000 cm-3 during the summer months and decreased to 200 - 500 cm-3 during the winter. These seasonal changes in aerosol number concentrations were correlated with the frequency of events typical of new particle formation. Measured sub-micron organic mass fractions were between 70 - 90% during the summer months, when new particle formation events were most frequent, suggesting the importance of organic species in the nucleation or growth process, or both. Aerosol composition derived from hygroscopicity measurements indicate organic mass fractions of 50 - 60% for particles with diameters larger than 0.15 μm during the winter. The composition of smaller diameter particles appeared to be organic dominated year-round. High organic mass fractions led to low values of aerosol hygroscopicity, described using the κ parameter. Over the entire year-long BEACHON study, κ had an average value of 0.16 ± 0.08, similar to values determined during biologically active periods in tropical and boreal forests, and lower than the commonly assumed value of κcontinental = 0.3. There was also an observed increase in κ with size, due to external mixing of the fine mode… Advisors/Committee Members: Kreidenweis, Sonia M. (advisor), Collett, Jeffrey L. (committee member), van den Heever, Susan C. (committee member), Ham, Jay (committee member).

Subjects/Keywords: aerosol; smoke; new particle formation; CCN

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APA (6^th Edition):

Levin, E. J. (2013). Remote continental aerosol characteristics in the Rocky Mountains of Colorado and Wyoming. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/78833

Chicago Manual of Style (16^th Edition):

Levin, Ezra JT. “Remote continental aerosol characteristics in the Rocky Mountains of Colorado and Wyoming.” 2013. Doctoral Dissertation, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/78833.

MLA Handbook (7^th Edition):

Levin, Ezra JT. “Remote continental aerosol characteristics in the Rocky Mountains of Colorado and Wyoming.” 2013. Web. 26 Feb 2021.

Vancouver:

Levin EJ. Remote continental aerosol characteristics in the Rocky Mountains of Colorado and Wyoming. [Internet] [Doctoral dissertation]. Colorado State University; 2013. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/78833.

Council of Science Editors:

Levin EJ. Remote continental aerosol characteristics in the Rocky Mountains of Colorado and Wyoming. [Doctoral Dissertation]. Colorado State University; 2013. Available from: http://hdl.handle.net/10217/78833

Colorado State University

19. Rambikur, Evan H. Evaluation of the Kipp and Zonen large aperture scintillometer for estimation of sensible heat flux over irrigated and non-irrigated fields in southeastern Colorado.

Degree: MS(M.S.), Civil and Environmental Engineering, 2012, Colorado State University

URL: http://hdl.handle.net/10217/75112

► The aim of this work was to assess the performance of the Kipp and Zonen Large Aperture Scintillometer (LAS; Delft, Netherlands) to predict surface sensible… (more)

▼ The aim of this work was to assess the performance of the Kipp and Zonen Large Aperture Scintillometer (LAS; Delft, Netherlands) to predict surface sensible heat flux (H). The LAS was introduced approximately 30 years ago and has been marketed as an indirect tool for the estimation of vegetation evapotranspiration (ET). Several tests have shown the LAS to be a fairly robust tool for prediction of H, both over homogeneous and heterogeneous surfaces. However, the Kipp and Zonen LAS has been criticized for overestimation of H and for significant inter-sensor deviation in H. Field experiments were performed in 2011 using three Kipp and Zonen LAS units over two different surfaces to assess the accuracy and inter-sensor variability. Accuracy was evaluated based on reference measurements from eddy covariance (EC) instrumentation, which provides direct measurement of sensible and latent heat fluxes. Notably the EC method has been criticized for systematic underestimation of the sensible and/or latent heat flux, but is nonetheless a common tool used to validate LAS data. The first experimental test site was predominantly dry and uniform grassland located near Timpas, CO. At this site, all three LAS units were deployed together for some time in order to assess inter-sensor variability and an EC system was installed for some duration of the LAS deployment. The EC system was subsequently moved to the second site, which was the Colorado State University (CSU) Arkansas Valley Research Center (AVRC) near Rocky Ford, CO. At the AVRC, one LAS unit was set up over irrigated alfalfa. Results from the inter-LAS comparison suggested that there may be some inherent variability between 6-11% in LAS-predicted H (HLAS) and that the physical alignment of the LAS is critical for maintaining good performance. Testing different methods for estimation of the friction velocity (u*) variable revealed bias between the logarithmic wind profile (LWP) result and the EC measurement. Linear regression slopes between 0.94 and 1.35 were found for HLAS with respect to EC-derived H (HEC) for the Timpas site - dependent on the LAS unit, the LAS alignment, and the u* method. The overall conclusion was that HLAS was reasonably accurate, partially due to the potential of HEC being underestimated on the basis of lack of energy balance closure. For the CSU AVRC (irrigated) site, HLAS was generally observed to be greater than HLAS by 20-30%. However, heat flux source area differences between the LAS and EC units may have contributed to some of the observed biases. Further, the overall conclusion of reasonable accuracy of HLAS was made, again partially due to potential for H underestimation by the EC system. It is recommended, nonetheless, for future applications to calibrate the Kipp and Zonen LAS to a reliable reference on the basis of observed inter-sensor variability. Further, the benefit of the LAS is judged to be higher for a scenario of limited or no irrigation than for one of full irrigation, since the contribution of H to the overall energy balance would be… Advisors/Committee Members: Chávez, José L. (advisor), Andales, Allan A. (committee member), Ham, Jay M. (committee member), Gates, Timothy K. (committee member).

Subjects/Keywords: energy balance; sensible heat flux; micrometeorology

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APA (6^th Edition):

Rambikur, E. H. (2012). Evaluation of the Kipp and Zonen large aperture scintillometer for estimation of sensible heat flux over irrigated and non-irrigated fields in southeastern Colorado. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/75112

Chicago Manual of Style (16^th Edition):

Rambikur, Evan H. “Evaluation of the Kipp and Zonen large aperture scintillometer for estimation of sensible heat flux over irrigated and non-irrigated fields in southeastern Colorado.” 2012. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/75112.

MLA Handbook (7^th Edition):

Rambikur, Evan H. “Evaluation of the Kipp and Zonen large aperture scintillometer for estimation of sensible heat flux over irrigated and non-irrigated fields in southeastern Colorado.” 2012. Web. 26 Feb 2021.

Vancouver:

Rambikur EH. Evaluation of the Kipp and Zonen large aperture scintillometer for estimation of sensible heat flux over irrigated and non-irrigated fields in southeastern Colorado. [Internet] [Masters thesis]. Colorado State University; 2012. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/75112.

Council of Science Editors:

Rambikur EH. Evaluation of the Kipp and Zonen large aperture scintillometer for estimation of sensible heat flux over irrigated and non-irrigated fields in southeastern Colorado. [Masters Thesis]. Colorado State University; 2012. Available from: http://hdl.handle.net/10217/75112

Colorado State University

20. Galles, Karen J. Practical strategies for reducing ammonia volatilization from feedlots along Colorado's Front Range.

Degree: MS(M.S.), Ecology, 2011, Colorado State University

URL: http://hdl.handle.net/10217/46901

► The Rocky Mountain National Park (RMNP) Initiative is a collaboration between state and federal agencies that has committed to achieving a 50% reduction (from 2004… (more)

▼ The Rocky Mountain National Park (RMNP) Initiative is a collaboration between state and federal agencies that has committed to achieving a 50% reduction (from 2004 levels) in N deposition in RMNP by 2032; current levels of N deposition have caused measureable changes in aquatic and terrestrial alpine ecosystems in the park. Northeastern Colorado, a region with a high concentration of livestock production, is likely one of the top two contributors to N deposition in RMNP. Reducing ammonia volatilization from Colorado's livestock sector will be important to achieving N deposition reduction goals in RMNP. To advance understanding of N loss from Colorado's feedlots, studies were done to examine: 1) the potential of reducing ammonia volatilization through lowering crude protein content in feedlot diets, 2) the effect of water sprinkling (a commonly prescribed dust control practice) on ammonia volatilization, and 3) the upper bound of ammonia flux from feedlot pen surfaces in Colorado. Two types of alternative feedlot diets - Oscillating N and Reduced N - were compared to a Control diet treatment and assessed for their effect on cattle performance and ammonia volatilization from pen surfaces. Intact pen surface samples were collected from November to March during a feeding trial from the three different diet treatments. Ammonia volatilization was measured under controlled conditions using a laboratory chamber system. The Reduced N diet (11.62% CP) significantly reduced cumulative 7-day ammonia emissions by 21 to 40% compared to the Control diet (13.5% CP). Average daily ammonia flux from Control diet samples ranged from 7.1 to 9.4 g NH3 m-2 d-1, while Reduced N diet samples had an average daily ammonia flux of 3.7 to 7.0 g NH3 m-2 d-1. There was no difference between the Oscillating N diet (11.62% CP 3 days/week and 13.5% CP 4 days/week) and the Control diet. Cattle performance (average daily gain) was not affected. A common feedlot practice to control dust and address frequent complaints from neighboring property owners and communities is to sprinkle the pen surface with water. Many feedlot operators have infrastructure in place - either solid set sprinklers on fencelines or water trucks that drive down the alleys - to sprinkle regularly during hot, dry conditions. The mechanics of ammonia volatilization suggest that watering could potentially increase N loss, but several studies suggest that water may have a suppressive effect on volatilization rates. Paired samples were taken from visibly obvious urine patches at a commercial feedlot in northeastern Colorado during July and August. In the laboratory, 5 mm of water - a typical amount of water applied for dust control - was applied to one sample from each pair, chosen randomly. Ammonia volatilization was then measured in a laboratory chamber system. Volatilization on the first day of measurement was 39.04 g NH3 m-2 d-1 for watered samples and 28.58 g NH3 m-2 d-1 for unwatered - a reduction of 27%. There was no difference in emissions on days 2 through 7 of measurement.… Advisors/Committee Members: Ham, Jay M. (advisor), Davis, J. G. (Jessica Gwyn), 1962- (committee member), Baron, Jill (committee member), Sharvelle, Sybil (committee member).

Subjects/Keywords: ammonia fluxes; nitrogen transport; nitrogen deposition; livestock; beef feedlots

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APA (6^th Edition):

Galles, K. J. (2011). Practical strategies for reducing ammonia volatilization from feedlots along Colorado's Front Range. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/46901

Chicago Manual of Style (16^th Edition):

Galles, Karen J. “Practical strategies for reducing ammonia volatilization from feedlots along Colorado's Front Range.” 2011. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/46901.

MLA Handbook (7^th Edition):

Galles, Karen J. “Practical strategies for reducing ammonia volatilization from feedlots along Colorado's Front Range.” 2011. Web. 26 Feb 2021.

Vancouver:

Galles KJ. Practical strategies for reducing ammonia volatilization from feedlots along Colorado's Front Range. [Internet] [Masters thesis]. Colorado State University; 2011. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/46901.

Council of Science Editors:

Galles KJ. Practical strategies for reducing ammonia volatilization from feedlots along Colorado's Front Range. [Masters Thesis]. Colorado State University; 2011. Available from: http://hdl.handle.net/10217/46901

Colorado State University

21. Fulgham, S. Ryan. Insights into the biosphere-atmosphere exchange of organic gases from seasonal observations over a ponderosa pine forest.

Degree: PhD, Chemistry, 2020, Colorado State University

URL: http://hdl.handle.net/10217/211809

► The biosphere-atmosphere exchange of organic gases over forests contributes to the formation of air pollution and the availability of forest nutrients. Forests can be both… (more)

▼ The biosphere-atmosphere exchange of organic gases over forests contributes to the formation of air pollution and the availability of forest nutrients. Forests can be both sources and sinks of volatile and semi-volatile organic compounds to the atmosphere. The role that forests play in controlling organic acid concentrations remains poorly understood, with multiple model-measurement comparisons reporting missing sources of formic acid. Large, missing sources of organic acids have been identified over different forested environments. Despite substantial seasonal variability in forest productivity and environmental conditions, a paucity of observations, during seasons other than summertime, is available. Although forest fires are a major source of hazardous organic gases and particulate matter, few measurements of semi-volatile organic compounds emitted by forest fires are available from within 1 km of the fire. Detection further-afield cannot disambiguate between chemistry at the source of the fire and chemical aging as a smoke plume traverses the atmosphere. Near-field observations are needed to characterize emissions attributable to combustion and pyrolysis processes. To improve understanding of processes that control the atmospheric budgets of organic acids, water-soluble pollutants with physicochemical properties similar to organic acids, and fire-emitted phenolic compounds, this dissertation reports measurements of the biosphere-atmosphere exchange of a suite of organic gases over a Rocky Mountain ponderosa pine forest in Colorado over four, seasonally-representative measurement campaigns. First, we report seasonally persistent, upward fluxes of organic acids, which are neither explained by direct emissions nor secondary production. Second, we present evidence for equilibrium partitioning into and out of water films on forest surfaces as both a missing source and sink of isocyanic acid and small alkanoic acids. Finally, we report significant enhancement of organic acids, phenolic compounds, and other nitrogen containing compounds during initiation of a controlled forest fire compared with the remainder of the burn. Nitrated phenols are rapidly produced and enhanced more than phenolic precursors during initial, higher temperature conditions. We attribute greater enhancement of nitrated phenols to high NOx emissions under higher temperature conditions. Advisors/Committee Members: Farmer, Delphine (advisor), Ham, Jay M. (committee member), Ravishankara, Akkihebbal R. (committee member), Van Orden, Alan (committee member).

Subjects/Keywords: CIMS; organic acids; surface wetness; flux; biosphere-atmosphere exchange; phenolic compounds

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APA (6^th Edition):

Fulgham, S. R. (2020). Insights into the biosphere-atmosphere exchange of organic gases from seasonal observations over a ponderosa pine forest. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/211809

Chicago Manual of Style (16^th Edition):

Fulgham, S Ryan. “Insights into the biosphere-atmosphere exchange of organic gases from seasonal observations over a ponderosa pine forest.” 2020. Doctoral Dissertation, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/211809.

MLA Handbook (7^th Edition):

Fulgham, S Ryan. “Insights into the biosphere-atmosphere exchange of organic gases from seasonal observations over a ponderosa pine forest.” 2020. Web. 26 Feb 2021.

Vancouver:

Fulgham SR. Insights into the biosphere-atmosphere exchange of organic gases from seasonal observations over a ponderosa pine forest. [Internet] [Doctoral dissertation]. Colorado State University; 2020. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/211809.

Council of Science Editors:

Fulgham SR. Insights into the biosphere-atmosphere exchange of organic gases from seasonal observations over a ponderosa pine forest. [Doctoral Dissertation]. Colorado State University; 2020. Available from: http://hdl.handle.net/10217/211809

Colorado State University

22. Lassman, William. Using modelling tools to advance the understanding of ammonia dry-deposition and bidirectional flux processes next to large animal feeding operations.

Degree: PhD, Atmospheric Science, 2020, Colorado State University

URL: http://hdl.handle.net/10217/208528

► Ammonia in the atmosphere is a trace gas that can play a big role in the Earth's climate, as well as human and ecological health.… (more)

▼ Ammonia in the atmosphere is a trace gas that can play a big role in the Earth's climate, as well as human and ecological health. Due to its stickiness and solubility, ammonia can enter the biosphere via wet and dry deposition, where excess ammonia input often results in soil acidification, disruption of natural ecological equilibria, and loss of biodiversity. Additionally, ammonia is the most abundant alkaline species in the atmosphere and can react with atmospheric acids to form aerosols, which can affect the earth's radiative balance as well as human health. Ammonia emissions tend to be associated with agricultural sources, such as fertilized fields or animal waste at concentrated Animal Feeding Operations (CAFOs). Consequently, ammonia emissions tend to be dynamic and highly heterogeneous, and ammonia surface-fluxes are difficult to measure. However, in regions with many large CAFOs, ammonia can be an important regional pollutant, especially if there are sensitive ecosystems or other regional sources of atmospheric acids present. In this dissertation, I study ammonia dry-deposition fluxes immediately downwind of CAFOs using a variety of modelling tools. First, I discuss original research where I use a coupled a K-epsilon model with a Lagrangian-Stochastic ammonia bidirectional exchange surface model to simulate the dispersion and deposition of ammonia downwind of an idealized CAFO. Based on these simulations, the amount of ammonia that undergoes dry deposition depends greatly on the land surface downwind of the CAFO; replacing bare soil or unmanaged grassland with leafier surfaces such as cropland or forests can increase the fraction of total ammonia emissions that deposits from 2 - 10% to 30 - 50%, though this is sensitive to the ammonia emission potential in the model plant canopy. Next, I describe a separate study where I use a 3-D Large-Eddy Simulation model to simulate the dispersion of ammonia and methane from a CAFO with a time-resolved modelling tool. I use this modelling system to produce synthetic observations, which are used to develop an inversion approach to quantify the ammonia dry deposition near a CAFO with colocated mobile measurements of ammonia and methane. While I demonstrate that such an inversion technique is feasible with surface-based measurements, considerable value is added, in terms of minimizing method bias and increasing method precision, by mounting measurements on a small Unmanned Aerial System (sUAS). Finally, I present measurements of PM2.5 concentration and composition that were made in Palapye, Botswana. Botswana is a developing country with a hot and arid climate. Beef and livestock production are important economic activities in Botswana; however, the agricultural practices differ considerably from the CAFOs discussed in the rest of the dissertation. Furthermore, these livestock activities occur against a backdrop of emissions and air pollutants that differ considerably from the United States and Europe. The measurements show that PM2.5 concentrations were on average 9 μg m-3… Advisors/Committee Members: Pierce, Jeffrey R. (advisor), Collett, Jeffrey L., Jr. (advisor), Fischer, Emily V. (committee member), Ham, Jay M. (committee member).

Subjects/Keywords: Botswana; dispersion; modelling; deposition; ammonia; feedlot

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Lassman, W. (2020). Using modelling tools to advance the understanding of ammonia dry-deposition and bidirectional flux processes next to large animal feeding operations. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/208528

Chicago Manual of Style (16^th Edition):

Lassman, William. “Using modelling tools to advance the understanding of ammonia dry-deposition and bidirectional flux processes next to large animal feeding operations.” 2020. Doctoral Dissertation, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/208528.

MLA Handbook (7^th Edition):

Lassman, William. “Using modelling tools to advance the understanding of ammonia dry-deposition and bidirectional flux processes next to large animal feeding operations.” 2020. Web. 26 Feb 2021.

Vancouver:

Lassman W. Using modelling tools to advance the understanding of ammonia dry-deposition and bidirectional flux processes next to large animal feeding operations. [Internet] [Doctoral dissertation]. Colorado State University; 2020. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/208528.

Council of Science Editors:

Lassman W. Using modelling tools to advance the understanding of ammonia dry-deposition and bidirectional flux processes next to large animal feeding operations. [Doctoral Dissertation]. Colorado State University; 2020. Available from: http://hdl.handle.net/10217/208528

Colorado State University

23. Wolding, Brandon. Vertically resolved weak temperature gradient analysis of the Madden-Julian Oscillation.

Degree: PhD, Atmospheric Science, 2017, Colorado State University

URL: http://hdl.handle.net/10217/181333

► Interactions between moisture, convection, and large-scale circulations are thought to play an important role in destabilizing the Madden-Julian Oscillation (MJO). A simplified framework for understanding… (more)

▼ Interactions between moisture, convection, and large-scale circulations are thought to play an important role in destabilizing the Madden-Julian Oscillation (MJO). A simplified framework for understanding such interactions is developed, building upon the work of Chikira (2014). Tropical weak temperature gradient (WTG) balance is used to diagnose intraseasonal variations in large-scale vertical velocity from variations in apparent heating, allowing intraseasonal variations in large-scale vertical moisture advection to be decomposed into contributions from various apparent heating processes (e.g. radiative heating, microphysical processes). The WTG diagnosis captures the vertical structure and magnitude of large-scale vertical velocity and vertical moisture advection with exceptional accuracy throughout the free troposphere. Moisture and moisture variance budgets are used to investigate the MJO in ERA-interim (ERAi) reanalysis and the Superparameterized Community Earth System Model (SP-CESM). Moisture budgets indicate that, during the enhanced phase of the MJO, anomalous moistening by large-scale vertical moisture advection exceeds anomalous drying by microphysical processes and sub-grid scale (SGS) eddy fluxes, such that the net effect of these large and opposing processes (hereafter the column process) is to further moisten regions that are anomalously moist. Moisture variance budgets indicate that the column process helps grow moisture variance, acting to destabilize the MJO. Horizontal advective damping of moisture variance, associated with the modulation of higher frequency convective variability on intraseasonal timescales, acts to stabilize the MJO. The vertically resolved WTG balance framework is used to assess the contribution various apparent heating processes make to the column process, and its ability to destabilize the MJO. Intraseasonal variations in longwave radiative heating enhance variations in large-scale vertical moisture advection at low and mid levels, strongly supporting destabilization of the MJO in both ERAi and SP-CESM. The effect of convection alone (i.e. without radiative and surface flux feedbacks) is to weakly grow moisture variance in SP-CESM, and weakly damp moisture variance in ERAi, suggesting that the MJO is unrealistically unstable in the former. Surface flux feedbacks appear to play a more important role in destabilizing the real world MJO. Moisture variance budget analysis of periods of weak, moderate, and strong MJO activity suggests that changes in the vertical structure of apparent heating do not play a dominant role in limiting the amplitude of the MJO in SP-CESM in the current climate. WTG balance provides a useful framework for investigating how the MJO, and its impacts, may change as the climate system warms. Two simulations of SP-CESM, one at pre-industrial levels of CO2 (280 ppm, hereafter PI) and one where CO2 levels have been quadrupled (1120 ppm, hereafter 4xCO2), were analyzed. MJO convective variability increases considerably in the 4xCO2 simulation, a consequence of… Advisors/Committee Members: Maloney, Eric (advisor), Randall, David (committee member), van den Heever, Susan (committee member), Kiladis, George (committee member), Ham, Jay (committee member).

Subjects/Keywords: convective aggregation; MJO; weak temperature gradient; climate; teleconnections; Madden-Julian oscillation

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Wolding, B. (2017). Vertically resolved weak temperature gradient analysis of the Madden-Julian Oscillation. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/181333

Chicago Manual of Style (16^th Edition):

Wolding, Brandon. “Vertically resolved weak temperature gradient analysis of the Madden-Julian Oscillation.” 2017. Doctoral Dissertation, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/181333.

MLA Handbook (7^th Edition):

Wolding, Brandon. “Vertically resolved weak temperature gradient analysis of the Madden-Julian Oscillation.” 2017. Web. 26 Feb 2021.

Vancouver:

Wolding B. Vertically resolved weak temperature gradient analysis of the Madden-Julian Oscillation. [Internet] [Doctoral dissertation]. Colorado State University; 2017. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/181333.

Council of Science Editors:

Wolding B. Vertically resolved weak temperature gradient analysis of the Madden-Julian Oscillation. [Doctoral Dissertation]. Colorado State University; 2017. Available from: http://hdl.handle.net/10217/181333

Colorado State University

24. Li, Yi. Characterizing ammonia concentrations and deposition in the United States.

Degree: PhD, Atmospheric Science, 2015, Colorado State University

URL: http://hdl.handle.net/10217/170348

► Rapid development of agricultural activities and fossil fuel combustion in the United States led to a great increase of reactive nitrogen (Nr) emissions in the… (more)

▼ Rapid development of agricultural activities and fossil fuel combustion in the United States led to a great increase of reactive nitrogen (Nr) emissions in the second half of the twentieth century. These emissions have been linked to excess nitrogen (N) deposition in natural ecosystems through dry and wet deposition pathways that can lead to adverse environmental impacts. Furthermore, as precursors of ozone and fine particles, reactive nitrogen species impact regional air quality with resulting effects on human health, visibility, and climate forcing. In this dissertation, ambient concentrations of reactive nitrogen species and their deposition are examined in the Rocky Mountain region and across the country. Particular emphasis is placed on ammonia, a currently unregulated pollutant, despite its important contributions both to nitrogen deposition and fine particle formation. Continuous measurements of the atmospheric trace gases ammonia (NH3) and nitric acid (HNO3) and of fine particle (PM2.5) ammonium (NH4+), nitrate (NO3-) and sulfate (SO42-) were conducted using a denuder/filter system from December 2006 to December 2011 at Boulder, Wyoming, a region of active gas production. The average five year concentrations of NH3, HNO3, NH4+, NO3- and SO42- were 0.17, 0.19, 0.26, 0.32, and 0.48 µg/m3, respectively. Significant seasonal patterns were observed. The concentration of NH3 was higher in the summer than in other seasons, consistent with increased NH3 emissions and a shift in the ammonium nitrate (NH4NO3) equilibrium toward the gas phase at higher temperatures. High HNO3 concentrations were observed both in the summer and the winter. Elevated wintertime HNO3 production appeared to be due to active local photochemistry in a shallow boundary layer over a reflective, snow-covered surface. PM2.5 NH4+ and SO42- concentrations peaked in summer while NO3- concentrations peaked in winter. Cold winter temperatures drove the NH3-HNO3-NH4NO3 equilibrium toward particulate NH4NO3. A lack of NH3, however, frequently resulted in substantial residual gas phase HNO3 even under cold winter conditions. Concentrated agricultural activities and animal feeding operations in the northeastern plains of Colorado represent an important source of atmospheric NH3 that contributes to regional fine particle formation and to nitrogen deposition to sensitive ecosystems in Rocky Mountain National Park (RMNP) located ~80 km to the west. In order to better understand temporal and spatial differences in NH3 concentrations in this source region, weekly concentrations of NH3 were measured at 14 locations during the summers of 2010 to 2014 using Radiello passive NH3 samplers. Weekly average NH3 concentrations ranged from 2.8 µg/m3 to 41.3 µg/m3 with the highest concentrations near large concentrated animal feeding operations (CAFOs). The annual summertime mean NH3 concentrations were stable in this region from 2010 to 2014, providing a baseline against which concentration changes associated with future changes in regional NH3 emissions can be… Advisors/Committee Members: Collett, Jeffrey L. (advisor), Kreidenweis, Sonia M. (committee member), Fischer, Emily (committee member), Ham, Jay (committee member).

Subjects/Keywords: ammonia; atmospheric chemistry; gas/particle partitioning; nitrogen deposition; passive sampler; PM2.5

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APA (6^th Edition):

Li, Y. (2015). Characterizing ammonia concentrations and deposition in the United States. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/170348

Chicago Manual of Style (16^th Edition):

Li, Yi. “Characterizing ammonia concentrations and deposition in the United States.” 2015. Doctoral Dissertation, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/170348.

MLA Handbook (7^th Edition):

Li, Yi. “Characterizing ammonia concentrations and deposition in the United States.” 2015. Web. 26 Feb 2021.

Vancouver:

Li Y. Characterizing ammonia concentrations and deposition in the United States. [Internet] [Doctoral dissertation]. Colorado State University; 2015. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/170348.

Council of Science Editors:

Li Y. Characterizing ammonia concentrations and deposition in the United States. [Doctoral Dissertation]. Colorado State University; 2015. Available from: http://hdl.handle.net/10217/170348

Colorado State University

25. Shonkwiler, Kira Brianne. Micrometeorological studies of a beef feedlot, dairy, and grassland: measurements of ammonia, methane, and energy balance closure.

Degree: PhD, Atmospheric Science, 2018, Colorado State University

URL: http://hdl.handle.net/10217/189389

► Ammonia emissions from concentrated animal feeding operations (CAFOs; most of which are beef feedlots) near the Colorado Front Range are suspected to be a large… (more)

▼ Ammonia emissions from concentrated animal feeding operations (CAFOs; most of which are beef feedlots) near the Colorado Front Range are suspected to be a large regional input of reactive nitrogen which has been found to accumulate and cause deleterious effects in nearby downwind Class I areas like Rocky Mountain National Park. Methane (CH4) is a strong greenhouse gas (GHG) emitted in large amounts from dairy anaerobic lagoons used for liquid manure management. Lagoon systems account for over half of the manure management-based CH4 emissions from agriculture in the US. There is a strong need for more emissions measurements from CAFOs like feedlots and dairies. For these data to be trusted, well-developed techniques must be utilized at emissions measurement sites and such techniques should be validated in ideal scenarios. Three micrometeorological studies were performed involving measurement of emissions using micrometeorological methods in the surface layer. The first study involved estimating summertime NH3 emissions from a 25,000-head beef feedlot in Northern Colorado. Two different NH3 sensors were used: a cavity ring down spectroscopy analyzer collected data at a single point while a long-path FTIR collected data along a 226-m long transect, both deployed along the same fenceline. Concentration data from these systems were used with two inverse dispersion models (FIDES, an inverse solution to the advection dispersion equation; and WindTrax, a backward Lagrangian stochastic model). Point sensor concentrations of NH3 were similar to line-integrated sensor concentrations suggesting some spatial uniformity in emissions. Emissions had a diurnal pattern (i.e., afternoon peak with minimum in early morning) that was driven by temperature. Emissions predicted by WindTrax were 25.2% higher than those from FIDES. Point vs. long-path measurements of NH3 had minimal effect on predicted emissions. The mean NH3 emission factor (EF) was 80 ± 39 g NH3 hd−1 d−1, with 40.0% of dietary-N emitted as NH3. The second study involved using eddy covariance and WindTrax to quantify CH4 emissions from a 3.9-ha anaerobic lagoon serving a 1400-head dairy in northern Colorado. Methane emissions followed a strong seasonal pattern correlated with temperature of the organic sludge layer on the bottom of the lagoon. Fluxes started increasing in late spring (May; ~10°C), increased rapidly in Jun (10-15°C) peaked in the summer (Jul/Aug; ~18-20°C) and remained high until mid-autumn (late Oct/early Nov; ~10°C). Fluxes then decreased and remained consistently low (up to 10 times less than peak emissions) until microbial activity ramped up again in May. The EC signal was very dependent on wind direction, with highest concentrations and fluxes associated with the direction of the lagoon. Gap-filled data showed a slight diurnal pattern to all seasons, with tenfold increases in diurnal values for summer over winter. Additionally, EFs for the lagoon varied by season with lows in the winter and highs in the summer with an annual mean of 819 ± 774 g CH4 hd-1… Advisors/Committee Members: Collett, Jeffrey L. (advisor), Ham, Jay M. (committee member), Kreidenweis, Sonia (committee member), Schumacher, Russ (committee member), Archibeque, Shawn (committee member).

Subjects/Keywords: dispersion modeling; energy balance closure; manure slurry methane emissions; eddy covariance; animal feeding operations; feedlot ammonia emissions

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APA (6^th Edition):

Shonkwiler, K. B. (2018). Micrometeorological studies of a beef feedlot, dairy, and grassland: measurements of ammonia, methane, and energy balance closure. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/189389

Chicago Manual of Style (16^th Edition):

Shonkwiler, Kira Brianne. “Micrometeorological studies of a beef feedlot, dairy, and grassland: measurements of ammonia, methane, and energy balance closure.” 2018. Doctoral Dissertation, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/189389.

MLA Handbook (7^th Edition):

Shonkwiler, Kira Brianne. “Micrometeorological studies of a beef feedlot, dairy, and grassland: measurements of ammonia, methane, and energy balance closure.” 2018. Web. 26 Feb 2021.

Vancouver:

Shonkwiler KB. Micrometeorological studies of a beef feedlot, dairy, and grassland: measurements of ammonia, methane, and energy balance closure. [Internet] [Doctoral dissertation]. Colorado State University; 2018. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/189389.

Council of Science Editors:

Shonkwiler KB. Micrometeorological studies of a beef feedlot, dairy, and grassland: measurements of ammonia, methane, and energy balance closure. [Doctoral Dissertation]. Colorado State University; 2018. Available from: http://hdl.handle.net/10217/189389

Colorado State University

26. Piña, Aaron Joshua. Social-ecological approach to managing agricultural ammonia emissions and nitrogen deposition in Rocky Mountain National Park, A.

Degree: PhD, Ecology, 2017, Colorado State University

URL: http://hdl.handle.net/10217/181440

► Atmospheric nitrogen (N) deposition is harmful to nutrient-limited mountain ecosystems. Annual wet deposition of total inorganic N in Rocky Mountain National Park (RMNP) is dominated… (more)

▼ Atmospheric nitrogen (N) deposition is harmful to nutrient-limited mountain ecosystems. Annual wet deposition of total inorganic N in Rocky Mountain National Park (RMNP) is dominated by ammonium, which primarily comes from agricultural sources. The most wet N deposition events between 1980 and 2015 occurred during summer months. The confluence of summertime mountain meteorology and the location of pollution sources are a perfect combination that leads to high values of wet N deposition in RMNP. In Chapter 2, we tested the importance of convection as a N transport mechanism in addition to large-scale east winds, typically associated with the summertime mountain-valley circulation on the eastern plains of Colorado. We characterized the meteorological transport by using the Weather Research and Forecasting model at 4/3-km horizontal resolution. We used passive tracers as a simplified representation of emissions from a single agricultural source in eastern Colorado during three summer precipitation events where wet N deposition values in RMNP were among the highest recorded in all summers between 1980 and 2015. In all three cases, anticyclones in north-central United States and monsoonal flow associated with the North American Monsoon brought together the necessary conditions for deep convection over RMNP. Output from our simulations suggested large-scale winds were responsible for slow and steady transport whereas convection was a rapid and intermittent form of transport. This chapter showed two scales of transport had an additive effect that led to high deposition of N in RMNP during the afternoon/evening hours of three case studies. Chapter 3 discusses the development of a pilot early warning system (PEWS) for agricultural operators to voluntarily and temporarily minimize emissions of NH3 during periods of upslope winds. The PEWS was created using trajectory analyses driven by outputs from an ensemble of numerical weather forecasts together with the climatological expertise of human forecasters. In this study, we discuss the methods for the PEWS and offer a preliminary analyses of 21 months of the PEWS based on deposition data from two sites in RMNP as wells as voluntary responses from agriculture managers and producers after warnings were issued. Results from this study showed that the PEWS accurately predicted 5 of 7 high N deposition weeks at the lower-elevation observation site, but only 3 of 8 high N deposition weeks at the higher-elevation observation site. With the higher-elevation site receiving pollution from sources both west and east of the Continental Divide, sources west of the Continental Divide would need to be included in the PEWS to capture all of the sources leading to deposition at the higher-elevation site. Sixty agricultural producers and managers from 39 of Colorado's agricultural operations volunteered for the PEWS, and a two-way line of communication between the producers and the scientists was formed. An average of 21 voluntary responses (s.d. 4.9) per warning occurred, with over 75% of the… Advisors/Committee Members: Denning, A. Scott (advisor), Ojima, Dennis S. (advisor), Schumacher, Russ S. (committee member), Baron, Jill S. (committee member), Ham, Jay M. (committee member).

Subjects/Keywords: mountain meteorology; Rocky Mountain National Park; wet deposition; nitrogen; agricultural emissions; social-ecology

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APA (6^th Edition):

Piña, A. J. (2017). Social-ecological approach to managing agricultural ammonia emissions and nitrogen deposition in Rocky Mountain National Park, A. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/181440

Chicago Manual of Style (16^th Edition):

Piña, Aaron Joshua. “Social-ecological approach to managing agricultural ammonia emissions and nitrogen deposition in Rocky Mountain National Park, A.” 2017. Doctoral Dissertation, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/181440.

MLA Handbook (7^th Edition):

Piña, Aaron Joshua. “Social-ecological approach to managing agricultural ammonia emissions and nitrogen deposition in Rocky Mountain National Park, A.” 2017. Web. 26 Feb 2021.

Vancouver:

Piña AJ. Social-ecological approach to managing agricultural ammonia emissions and nitrogen deposition in Rocky Mountain National Park, A. [Internet] [Doctoral dissertation]. Colorado State University; 2017. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/181440.

Council of Science Editors:

Piña AJ. Social-ecological approach to managing agricultural ammonia emissions and nitrogen deposition in Rocky Mountain National Park, A. [Doctoral Dissertation]. Colorado State University; 2017. Available from: http://hdl.handle.net/10217/181440

Colorado State University

27. Speckman, Heather. Forest respiration from eddy covariance and chamber measurements under high turbulence and a bark beetle epidemic.

Degree: MS(M.S.), Ecology, 2013, Colorado State University

URL: http://hdl.handle.net/10217/81084

► Eddy covariance (EC) enables continuous estimates of carbon, water, and energy fluxes, and a global network of >500 sites (www.fluxnet.ornl.gov) has resulted in major advances… (more)

▼ Eddy covariance (EC) enables continuous estimates of carbon, water, and energy fluxes, and a global network of >500 sites (www.fluxnet.ornl.gov) has resulted in major advances in understanding ecosystem-scale biogeochemical cycling. However, long-term sums of net ecosystem exchange, photosynthesis and respiration fluxes have uncertainties because of potential measurement biases in respiration fluxes at night. Many studies have demonstrated that EC estimations of flux during the night are lower than chamber measurements – with low turbulence at night potentially causing the difference. A bark beetle outbreak at the GLEES Ameriflux site provided a unique opportunity to compare chamber and EC estimates of ecosystem respiration (R) under conditions of high turbulence (summer night mean u* = 0.7 m s-1) and 85% mortality of the aboveground respiring biomass due to a bark beetle epidemic. Chamber-based estimates of R were developed from periodic foliage, wood and soil CO2 efflux measurements fit to models of phenological seasonal change and diurnal temperature response. These models estimated ecosystem mean nightly respiration to have declined 32% after the bark beetle epidemic (7.0 ±0.22 μmol m-2 s-1 in 2005 to 4.8 ±0.16 μmol m-2 s-1 in 2011). The decrease was entirely due to the loss of aboveground respiration, soil efflux remained constant throughout the epidemic. Unlike chamber estimates, nighttime EC measurements did not decline after 85% of the forest basal area had been infested or killed by bark beetles, mean nighttime NEE of 3.0 μmol m-2 s-1 for 2005 and 2011. These EC values were significantly lower than chamber estimates of respiration for the same time periods (58% lower in 2005, and 34% in 2011). Despite the large difference in values, the two estimates of R were correlated (yearly r2 ranging from 0.18-0.60). This study suggests that the traditional discrepancy of nighttime EC and chamber estimates of ecosystem respiration are not caused by insufficient turbulence (results proved robust to extreme u* filter > 0.7 m s-1). Other sources of error are investigated for both techniques. To further explore this discrepancy, we suggest the installation of a second EC system below the canopy to improve understanding of air flows and fluxes throughout the ecosystem. This discrepancy must be resolved before scientific confidence can be attained in the true value of ecosystem carbon flux. Advisors/Committee Members: Ryan, Michael G. (advisor), Parton, William J. (advisor), Ham, Jay M. (committee member), Denning, A. Scott (committee member).

Subjects/Keywords: bark beetles; chamber; ecosystem respiration; eddy covariance; turbulence; u* filtering

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APA (6^th Edition):

Speckman, H. (2013). Forest respiration from eddy covariance and chamber measurements under high turbulence and a bark beetle epidemic. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/81084

Chicago Manual of Style (16^th Edition):

Speckman, Heather. “Forest respiration from eddy covariance and chamber measurements under high turbulence and a bark beetle epidemic.” 2013. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/81084.

MLA Handbook (7^th Edition):

Speckman, Heather. “Forest respiration from eddy covariance and chamber measurements under high turbulence and a bark beetle epidemic.” 2013. Web. 26 Feb 2021.

Vancouver:

Speckman H. Forest respiration from eddy covariance and chamber measurements under high turbulence and a bark beetle epidemic. [Internet] [Masters thesis]. Colorado State University; 2013. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/81084.

Council of Science Editors:

Speckman H. Forest respiration from eddy covariance and chamber measurements under high turbulence and a bark beetle epidemic. [Masters Thesis]. Colorado State University; 2013. Available from: http://hdl.handle.net/10217/81084

Colorado State University

28. Shadman, Soran. Measurement of ammonia emission from agricultural sites using open-path cavity ring-down spectroscopy and wavelength modulation spectroscopy based analyzers.

Degree: PhD, Mechanical Engineering, 2018, Colorado State University

URL: http://hdl.handle.net/10217/191453

► Agricultural activities and animal feedlot operations are the primary sources of emitted ammonia into the atmosphere. In the US, 4 Tg of ammonia is emitted… (more)

▼ Agricultural activities and animal feedlot operations are the primary sources of emitted ammonia into the atmosphere. In the US, 4 Tg of ammonia is emitted every year into the atmosphere which ~%75 of that is due to these major sources. Ammonia is the third most abundant nitrogen containing species in the atmosphere and it has important impacts on atmospheric chemistry, health, and the environment. It is a precursor to the formation of aerosols and its deposition in pristine and aquatic systems leads to changes in ecosystem properties. Quantifying the dry deposition rate of ammonia in the first few kilometers of feedlots is crucial for better understanding the impacts of livestock and agricultural operations on environment. Therefore, fast, precise, and portable sensors are needed to quantify ammonia emission from its major sources. Absorption spectroscopy is a reliable technique by which compact and sensitive sensors can be developed for ammonia (and other gaseous species) detection. An open-path absorption spectroscopy based sensor allows ambient air to flow directly through its measurement region which leads to high-sensitivity and fast-response measurements. In this study, two open-path absorption based ammonia sensors using two techniques are developed: cavity ring-down spectroscopy (CRDS) and wavelength modulation spectroscopy (WMS). The CRDS and WMS based sensors show the sensitivity of ~1.5 ppb (at 1 second) and ~4 ppb (at 1 second), respectively. In both sensors, a quantum cascade laser (QCL) is utilized as the light source to cover the strongest absorption feature of ammonia in the mid-infrared (MIR) spectral region. It is the first demonstration of an open-path CRDS based sensor working in mid-infrared MIR, to our knowledge. The WMS based sensor developed in this study is low power (~25 W) and relatively lightweight (~4 kg). The low power consumption and compact size enables the sensor to be deployed on a commercialized unmanned aerial system (UAS) for aerial measurements. The combination of this sensor and another compact CRDS based methane sensor is used for simultaneous measurements of ammonia and methane (ground based and aerial). Methane is another important species emitted from the feedlots with a long lifetime (~10 years). It is nonreactive and thus not lost by dry deposition. Therefore, methane concentration is only influenced by dispersion while the ammonia concentration is affected by both deposition and dispersion. The dry deposition of ammonia nearby the concentrated animal feeding operations (CAFOs), as one of the major sources of ammonia, can be determined by measuring the decrease in the [NH3]/[CH4] ratio downwind. Advisors/Committee Members: Yalin, Azer P. (advisor), Marchese, Anthony J. (committee member), Olsen, Daniel B. (committee member), Ham, Jay (committee member).

Subjects/Keywords: laser; air pollution; spectroscopy

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APA (6^th Edition):

Shadman, S. (2018). Measurement of ammonia emission from agricultural sites using open-path cavity ring-down spectroscopy and wavelength modulation spectroscopy based analyzers. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/191453

Chicago Manual of Style (16^th Edition):

Shadman, Soran. “Measurement of ammonia emission from agricultural sites using open-path cavity ring-down spectroscopy and wavelength modulation spectroscopy based analyzers.” 2018. Doctoral Dissertation, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/191453.

MLA Handbook (7^th Edition):

Shadman, Soran. “Measurement of ammonia emission from agricultural sites using open-path cavity ring-down spectroscopy and wavelength modulation spectroscopy based analyzers.” 2018. Web. 26 Feb 2021.

Vancouver:

Shadman S. Measurement of ammonia emission from agricultural sites using open-path cavity ring-down spectroscopy and wavelength modulation spectroscopy based analyzers. [Internet] [Doctoral dissertation]. Colorado State University; 2018. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/191453.

Council of Science Editors:

Shadman S. Measurement of ammonia emission from agricultural sites using open-path cavity ring-down spectroscopy and wavelength modulation spectroscopy based analyzers. [Doctoral Dissertation]. Colorado State University; 2018. Available from: http://hdl.handle.net/10217/191453

29. Greer, Kyle C. Development of a low-firepower biomass dust combustor.

Degree: MS(M.S.), Mechanical Engineering, 2018, Colorado State University

URL: http://hdl.handle.net/10217/193122

► As of 2017, the World Health Organization estimates that 2.3 billion people globally lack access to basic sanitation facilities such as toilets or latrines. 892… (more)

Subjects/Keywords: dust; combustion; feces

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APA (6^th Edition):

Greer, K. C. (2018). Development of a low-firepower biomass dust combustor. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/193122

Chicago Manual of Style (16^th Edition):

Greer, Kyle C. “Development of a low-firepower biomass dust combustor.” 2018. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/193122.

MLA Handbook (7^th Edition):

Greer, Kyle C. “Development of a low-firepower biomass dust combustor.” 2018. Web. 26 Feb 2021.

Vancouver:

Greer KC. Development of a low-firepower biomass dust combustor. [Internet] [Masters thesis]. Colorado State University; 2018. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/193122.

Council of Science Editors:

Greer KC. Development of a low-firepower biomass dust combustor. [Masters Thesis]. Colorado State University; 2018. Available from: http://hdl.handle.net/10217/193122

30. Costa Filho, Edson. Modeling sensible heat flux for vegetated surfaces through an optimized surface aerodynamic temperature approach.

Degree: MS(M.S.), Civil and Environmental Engineering, 2019, Colorado State University

URL: http://hdl.handle.net/10217/197446

► Agricultural water management advancements rely on improved methods to accurately determine crop water use. Crop evapotranspiration modeling based on the surface energy balance depends on… (more)

▼ Agricultural water management advancements rely on improved methods to accurately determine crop water use. Crop evapotranspiration modeling based on the surface energy balance depends on the accurate estimation of all incoming and outgoing heat fluxes at the surface level. This thesis particularly goal is to improve sensible heat flux estimates for row crops through an optimized aerodynamic surface temperature (To) approach based on remote sensing and weather data. Empirical linear and non-linear To models were developed based on percent cover, surface temperature, air temperature, and a new variable named turbulent mixing row resistance using data collected at the USDA-ARS Research Farm located in Greeley (CO). The experiment took place in two sub-surface drip irrigation corn fields with different irrigation water management practices in 2017-2018. Sensible heat flux were measured using LAS, eddy covariance, aerodynamic profile, and Bowen ratio methods. Remote sensing data were measured on-site using a radiometer. The fields were considered a point in space. Data from Aimes (IA) and Rocky Ford (CO) were used to assess proposed model performances under different locations and in comparison to published To models. The results have indicated that the optimized linear To models performed better than the non-linear and published models approaches, indicating that the introduction of percent cover and the new variable has provided reliable results under different data sets. The linear proposed To approaches improved sensible heat flux estimation, on average, in 33 % and 28 % for the deficit and fully irrigated field at LIRF in comparison to the sensible heat based on published To models. Sensible heat flux modeling results were better for the modeling approaches considering the empirical linear To model than the non-linear approaches for all three data set tested. Advisors/Committee Members: Chavez, Jose L. (advisor), Ham, Jay M. (committee member), Venayagamoorthy, Karan (committee member).

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APA (6^th Edition):

Costa Filho, E. (2019). Modeling sensible heat flux for vegetated surfaces through an optimized surface aerodynamic temperature approach. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/197446

Chicago Manual of Style (16^th Edition):

Costa Filho, Edson. “Modeling sensible heat flux for vegetated surfaces through an optimized surface aerodynamic temperature approach.” 2019. Masters Thesis, Colorado State University. Accessed February 26, 2021. http://hdl.handle.net/10217/197446.

MLA Handbook (7^th Edition):

Costa Filho, Edson. “Modeling sensible heat flux for vegetated surfaces through an optimized surface aerodynamic temperature approach.” 2019. Web. 26 Feb 2021.

Vancouver:

Costa Filho E. Modeling sensible heat flux for vegetated surfaces through an optimized surface aerodynamic temperature approach. [Internet] [Masters thesis]. Colorado State University; 2019. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10217/197446.

Council of Science Editors:

Costa Filho E. Modeling sensible heat flux for vegetated surfaces through an optimized surface aerodynamic temperature approach. [Masters Thesis]. Colorado State University; 2019. Available from: http://hdl.handle.net/10217/197446

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