+publisher:"Colorado State University" +contributor:("Rutledge, Steven A.")

Colorado State University

1. Meyer, Tiffany C. Radar and lightning analyses of gigantic jet-producing storms.

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

URL: http://hdl.handle.net/10217/71928

► An analysis of the storm structure and evolution associated with six gigantic jets was conducted. Three of these gigantic jets were observed within detection range… (more)

Subjects/Keywords: gigantic jet; radar; lightning; GJ

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APA (6^th Edition):

Meyer, T. C. (2012). Radar and lightning analyses of gigantic jet-producing storms. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/71928

Chicago Manual of Style (16^th Edition):

Meyer, Tiffany C. “Radar and lightning analyses of gigantic jet-producing storms.” 2012. Masters Thesis, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/71928.

MLA Handbook (7^th Edition):

Meyer, Tiffany C. “Radar and lightning analyses of gigantic jet-producing storms.” 2012. Web. 25 Feb 2021.

Vancouver:

Meyer TC. Radar and lightning analyses of gigantic jet-producing storms. [Internet] [Masters thesis]. Colorado State University; 2012. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/71928.

Council of Science Editors:

Meyer TC. Radar and lightning analyses of gigantic jet-producing storms. [Masters Thesis]. Colorado State University; 2012. Available from: http://hdl.handle.net/10217/71928

Colorado State University

2. Rocque, Marquette N. Intraseasonal and diurnal variations of precipitation features observed during DYNAMO.

Degree: MS(M.S.), Atmospheric Science, 2020, Colorado State University

URL: http://hdl.handle.net/10217/219508

► The diurnal cycle (DC) of rainfall over the tropical oceans and within the Madden–Julian oscillation (MJO) has been investigated in numerous studies, but there has… (more)

▼ The diurnal cycle (DC) of rainfall over the tropical oceans and within the Madden–Julian oscillation (MJO) has been investigated in numerous studies, but there has been limited research on how the DC of precipitation and convective organization evolve throughout phases of the MJO over the open ocean. Cloud and precipitation parameterizations in models have been the source of low MJO predictability, so understanding the fundamental convective processes occurring within the MJO, both on the intraseasonal and diurnal timescales, will be beneficial in improving these model simulations. This study employs measurements collected during the Dynamics of the MJO (DYNAMO) field campaign (1 Oct. – 4 Dec. 2011) to investigate how the distribution of precipitation features (PFs) varies across MJO phase groups, throughout the day, and on-/off-equator. PFs identified from radar volume scans at the R/V Roger Revelle (80.5°E, 0°N) and R/V Mirai (80.5°E, 8°S) were classified into five morphologies based on shape and size. Additionally, several environmental parameters including sea surface temperature (SST), convective available potential energy (CAPE), and latent and sensible heat fluxes were analyzed to understand local interactions between the ocean, atmosphere, and convection. The largest rain events occurred during MJO phases 2&3 at the Revelle. Mesoscale events were found in all phase groups at the Mirai. However, convection was generally weaker at the Mirai, most likely due to extremely dry air (RH < 20%) in the mid-troposphere, and little variation in SST. Two westerly wind bursts (WWBs) were observed in phases 2&3 of the second MJO event (21–30 Nov.) at the Revelle which enhanced surface winds and air–sea fluxes and allowed stratiform precipitation to persist. Additionally, these WWBs enhanced the near-surface equatorial current known as the Yoshida–Wyrtki jet, which caused a large amount of upper ocean mixing and significantly cooled SSTs into December. The DC of rainfall was greatest during phases 8&1 and 2&3 at the Revelle with peaks in rain rate occurring in the afternoon and early morning hours. The afternoon peak was attributed to isolated and sub-MCS nonlinear PFs, apparently forced by SST heating and significant air–sea fluxes. These features then grew upscale through the evening into MCS nonlinear events, peaking in intensity just after midnight. MCS nonlinear features contributed the most to the rain volume during phases 2&3 at the Revelle at roughly 70%. Isolated and sub-MCS nonlinear features were the dominant mode of convection during the suppressed phases at the Revelle (4&5 and 6&7). Mesoscale systems were not observed in these two phase groups. MCS nonlinear systems were found in at least 15% of all radar scans for each phase group at the Mirai, and there was significantly less variability in environmental parameters between phase groups. Additionally, the DC of SST at the Mirai was much weaker than at the Revelle, which was attributed to enhanced surface winds that mixed out any diurnal warm layers. Thus, it… Advisors/Committee Members: Rutledge, Steven A. (advisor), Maloney, Eric D. (committee member), Chandrasekar, V. (committee member).

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APA (6^th Edition):

Rocque, M. N. (2020). Intraseasonal and diurnal variations of precipitation features observed during DYNAMO. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/219508

Chicago Manual of Style (16^th Edition):

Rocque, Marquette N. “Intraseasonal and diurnal variations of precipitation features observed during DYNAMO.” 2020. Masters Thesis, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/219508.

MLA Handbook (7^th Edition):

Rocque, Marquette N. “Intraseasonal and diurnal variations of precipitation features observed during DYNAMO.” 2020. Web. 25 Feb 2021.

Vancouver:

Rocque MN. Intraseasonal and diurnal variations of precipitation features observed during DYNAMO. [Internet] [Masters thesis]. Colorado State University; 2020. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/219508.

Council of Science Editors:

Rocque MN. Intraseasonal and diurnal variations of precipitation features observed during DYNAMO. [Masters Thesis]. Colorado State University; 2020. Available from: http://hdl.handle.net/10217/219508

Colorado State University

3. Loftus, Adrian Matthew. Triple-moment bulk hail microphysics scheme to investigate the sensitivities of hail to aerosols, A.

Degree: PhD, Atmospheric Science, 2012, Colorado State University

URL: http://hdl.handle.net/10217/67571

► Hail is a frequent occurrence in warm season deep convection in many mid-latitude regions and causes significant damage to property and agricultural interests every year.… (more)

▼ Hail is a frequent occurrence in warm season deep convection in many mid-latitude regions and causes significant damage to property and agricultural interests every year. Hail can also have a substantial impact on the precipitation characteristics of deep convection as well as on the dynamic and thermodynamic properties of convective downdrafts and cold-pools, which in turn can affect storm evolution and propagation. In addition, large and often destructive hail commonly occurs in severe convection, yet most one- (1M) and two-moment (2M) bulk microphysics schemes in cloud-resolving numerical models are incapable of producing large hail (diameter D ≥ 2 cm). The limits imposed by fixing one or two of the distribution parameters in these schemes often lead to particularly poor representations of particles within the tails of size distribution spectra; an especially important consideration for hail, which covers a broad range of sizes in nature. In order to improve the representation of hail distributions in simulations of deep moist convection in a cloud-resolving numerical model, a new triple-moment bulk hail microphysics scheme (3MHAIL) is presented and evaluated. The 3MHAIL scheme predicts the relative dispersion parameter for a gamma distribution function via the prediction of the sixth moment (related to the reflectivity factor) of the distribution in addition to the mass mixing ratio and number concentration (third and zeroeth moments, respectively) thereby allowing for a fully prognostic distribution function. Initial testing of this scheme reveals significant improvement in the representation of sedimentation, melting, and formation processes of hail compared to lower-order moment schemes. The 3MHAIL scheme is verified in simulations of a well-observed supercell storm that occurred over northwest Kansas on 29 June 2000 during the Severe Thunderstorm and Electrification and Precipitation Study (STEPS). Comparisons of the simulation results with the observations for this case, as well as with results of simulations using two different 2M microphysics schemes, suggest a significant improvement of the simulated storm structure and evolution is achieved with the 3MHAIL scheme. The generation of large hail and subsequent fallout in the simulation using 3MHAIL microphysics show particularly good agreement with surface hail reports for this storm as well as with previous studies of hail in supercell storms. On the other hand, the simulation with 2M microphysics produces only small hail aloft and virtually no hail at the surface, whereas a two-moment version of the 3MHAIL scheme (with a fixed relative dispersion parameter) produces unrealistically high amounts of large hail at low levels as a result of artificial shifts in the hail size spectra towards larger diameter hail during the melting process. The 3MHAIL scheme is also used to investigate the impact of changing the concentrations of aerosols that act as cloud condensation nuclei (CCN) on hail for the 29 June 2000 supercell case. For the simulated supercells in the… Advisors/Committee Members: Cotton, William R. (advisor), Rutledge, Steven A. (committee member), van den Heever, Susan C. (committee member), Bringi, Viswanathan N. (committee member).

Subjects/Keywords: aerosols; convection; hail; microphysics; numerical model; supercell

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APA (6^th Edition):

Loftus, A. M. (2012). Triple-moment bulk hail microphysics scheme to investigate the sensitivities of hail to aerosols, A. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/67571

Chicago Manual of Style (16^th Edition):

Loftus, Adrian Matthew. “Triple-moment bulk hail microphysics scheme to investigate the sensitivities of hail to aerosols, A.” 2012. Doctoral Dissertation, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/67571.

MLA Handbook (7^th Edition):

Loftus, Adrian Matthew. “Triple-moment bulk hail microphysics scheme to investigate the sensitivities of hail to aerosols, A.” 2012. Web. 25 Feb 2021.

Vancouver:

Loftus AM. Triple-moment bulk hail microphysics scheme to investigate the sensitivities of hail to aerosols, A. [Internet] [Doctoral dissertation]. Colorado State University; 2012. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/67571.

Council of Science Editors:

Loftus AM. Triple-moment bulk hail microphysics scheme to investigate the sensitivities of hail to aerosols, A. [Doctoral Dissertation]. Colorado State University; 2012. Available from: http://hdl.handle.net/10217/67571

Colorado State University

4. Thompson, Elizabeth Jennifer. Development of a polarimetric radar based hydrometeor classification algorithm for winter precipitation.

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

URL: http://hdl.handle.net/10217/72363

► The nation-wide WSR-88D radar network is currently being upgraded for dual-polarized technology. While many convective, warm-season fuzzy-logic hydrometeor classification algorithms based on this new suite… (more)

▼ The nation-wide WSR-88D radar network is currently being upgraded for dual-polarized technology. While many convective, warm-season fuzzy-logic hydrometeor classification algorithms based on this new suite of radar variables and temperature have been refined, less progress has been made thus far in developing hydrometeor classification algorithms for winter precipitation. Unlike previous studies, the focus of this work is to exploit the discriminatory power of polarimetric variables to distinguish the most common precipitation types found in winter storms without the use of temperature as an additional variable. For the first time, detailed electromagnetic scattering of plates, dendrites, dry aggregated snowflakes, rain, freezing rain, and sleet are conducted at X-, C-, and S-band wavelengths. These physics-based results are used to determine the characteristic radar variable ranges associated with each precipitation type. A variable weighting system was also implemented in the algorithm's decision process to capitalize on the strengths of specific dual-polarimetric variables to discriminate between certain classes of hydrometeors, such as wet snow to indicate the melting layer. This algorithm was tested on observations during three different winter storms in Colorado and Oklahoma with the dual-wavelength X- and S-band CSU-CHILL, C-band OU-PRIME, and X-band CASA IP1 polarimetric radars. The algorithm showed success at all three frequencies, but was slightly more reliable at X-band because of the algorithm's strong dependence on specific differential phase. While plates were rarely distinguished from dendrites, the latter were satisfactorily differentiated from dry aggregated snowflakes and wet snow. Sleet and freezing rain could not be distinguished from rain or light rain based on polarimetric variables alone. However, high-resolution radar observations illustrated the refreezing process of raindrops into ice pellets, which has been documented before but not yet explained. Persistent, robust patterns of decreased correlation coefficient, enhanced differential reflectivity, and an inflection point around enhanced reflectivity occurred over the exact depth of the surface cold layer indicated by atmospheric soundings during times when sleet was reported at the surface. It is hypothesized that this refreezing signature is produced by a modulation of the drop size distribution such that smaller drops preferentially freeze into ice pellets first. The melting layer detection algorithm and fall speed spectra from vertically pointing radar also captured meaningful trends in the melting layer depth, height, and mean correlation coefficient during this transition from freezing rain to sleet at the surface. These findings demonstrate that this new radar-based winter hydrometeor classification algorithm is applicable for both research and operational sectors. Advisors/Committee Members: Rutledge, Steven A. (advisor), Dolan, Brenda (committee member), Chandrasekar, V. (committee member), van den Heever, Susan (committee member).

Subjects/Keywords: winter; algorithm; radar; polarimetric

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APA (6^th Edition):

Thompson, E. J. (2012). Development of a polarimetric radar based hydrometeor classification algorithm for winter precipitation. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/72363

Chicago Manual of Style (16^th Edition):

Thompson, Elizabeth Jennifer. “Development of a polarimetric radar based hydrometeor classification algorithm for winter precipitation.” 2012. Masters Thesis, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/72363.

MLA Handbook (7^th Edition):

Thompson, Elizabeth Jennifer. “Development of a polarimetric radar based hydrometeor classification algorithm for winter precipitation.” 2012. Web. 25 Feb 2021.

Vancouver:

Thompson EJ. Development of a polarimetric radar based hydrometeor classification algorithm for winter precipitation. [Internet] [Masters thesis]. Colorado State University; 2012. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/72363.

Council of Science Editors:

Thompson EJ. Development of a polarimetric radar based hydrometeor classification algorithm for winter precipitation. [Masters Thesis]. Colorado State University; 2012. Available from: http://hdl.handle.net/10217/72363

Colorado State University

5. Shen, Xinhua. Aqueous phase sulfate production in clouds at Mt. Tai in eastern China.

Degree: PhD, Atmospheric Science, 2011, Colorado State University

URL: http://hdl.handle.net/10217/50158

► Clouds play an important role in the oxidation of sulfur dioxide to sulfate, since aqueous phase sulfur dioxide oxidation is typically much faster than oxidation… (more)

▼ Clouds play an important role in the oxidation of sulfur dioxide to sulfate, since aqueous phase sulfur dioxide oxidation is typically much faster than oxidation in the gas phase. Important aqueous phase oxidants include hydrogen peroxide, ozone and oxygen (catalyzed by trace metals). Because quantities of emitted sulfur dioxide in China are so large, however, it is possible that they exceed the capacity of regional clouds for sulfate production, leading to enhanced long-range transport of emitted SO2 and its oxidation product, sulfate. In order to assess the ability of regional clouds to support aqueous sulfur oxidation, four field campaigns were conducted in 2007 and 2008 at Mt. Tai in eastern China. Single and 2-stage Caltech Active Strand Cloudwater Collectors were used to collect bulk and drop size-resolved cloudwater samples, respectively. Key species that determine aqueous phase sulfur oxidation were analyzed, including cloudwater pH, S(IV), H2O2, Fe, and Mn. Gas phase SO2, O3, and H2O2 were also measured continuously during the campaigns. Other species in cloudwater, including inorganic ions, total organic carbon (TOC), formaldehyde, and organic acids were also analyzed to provide a fuller view of cloud chemistry in the region. Numerous periods of cloud interception/fog occurred during the four Mt. Tai field campaigns; more than 500 cloudwater samples were collected in total. A wide range of cloud pH values was observed, from 2.6 to 7.6. SO42-, NO3-, and NH4+ were the major inorganic species for all four campaigns. TOC concentrations were also very high in some samples (up to 200 ppmC), especially when clouds were impacted by emissions from agricultural biomass burning. Back-trajectory analysis also indicated influence by dust transport from northern China in a few spring cloud events. Differences between the compositions of small and large cloud droplets were observed, but generally found to be modest for major solute species and pH. Mt. Tai clouds were found to interact strongly with PM2.5 sulfate, nitrate, and ammonium with average scavenging efficiencies of 80%, 75%, and 78%, respectively, across 7 events studied. Scavenging efficiencies for total sulfur (PM2.5 sulfate plus gaseous sulfur dioxide), however, averaged only 43%, indicating the majority of gaseous sulfur dioxide remained unprocessed in these cloud events. H2O2 was found to be the most important oxidant for aqueous sulfate production 68% of the time. High concentrations of residual H2O2 were measured in some samples, especially during summertime, implying a substantial capacity for additional sulfur oxidation. The importance of ozone as a S(IV) oxidant increased substantially as cloud pH climbed above pH 5 to 5.3. Overall, ozone was found to be the most important aqueous S(IV) oxidant in 21% of the sampling periods. Trace metal-catalyzed S(IV) autooxidation was determined to be the fastest aqueous sulfate production pathway in the remaining 11% of the cases. Complexation with formaldehyde was also found to be a potentially… Advisors/Committee Members: Collett, Jeffrey L. (advisor), Kreidenweis, Sonia M. (committee member), Rutledge, Steven A. (committee member), Reynolds, Stephen J. (committee member).

Subjects/Keywords: aqueous phase oxidation; China; clouds; Mt. Tai; sulfate; sulfur dioxide

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APA (6^th Edition):

Shen, X. (2011). Aqueous phase sulfate production in clouds at Mt. Tai in eastern China. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/50158

Chicago Manual of Style (16^th Edition):

Shen, Xinhua. “Aqueous phase sulfate production in clouds at Mt. Tai in eastern China.” 2011. Doctoral Dissertation, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/50158.

MLA Handbook (7^th Edition):

Shen, Xinhua. “Aqueous phase sulfate production in clouds at Mt. Tai in eastern China.” 2011. Web. 25 Feb 2021.

Vancouver:

Shen X. Aqueous phase sulfate production in clouds at Mt. Tai in eastern China. [Internet] [Doctoral dissertation]. Colorado State University; 2011. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/50158.

Council of Science Editors:

Shen X. Aqueous phase sulfate production in clouds at Mt. Tai in eastern China. [Doctoral Dissertation]. Colorado State University; 2011. Available from: http://hdl.handle.net/10217/50158

Colorado State University

6. Lerach, David Gregory. Simulating southwestern U.S. desert dust influences on severe, tornadic storms.

Degree: PhD, Atmospheric Science, 2012, Colorado State University

URL: http://hdl.handle.net/10217/67575

► In this study, three-dimensional numerical simulations were performed using the Regional Atmospheric Modeling System (RAMS) model to investigate possible southwestern U.S. desert dust impacts on… (more)

▼ In this study, three-dimensional numerical simulations were performed using the Regional Atmospheric Modeling System (RAMS) model to investigate possible southwestern U.S. desert dust impacts on severe, tornadic storms. Initially, two sets of simulations were conducted for an idealized supercell thunderstorm. In the first set, two numerical simulations were performed to assess the impacts of increased aerosol concentrations acting as cloud condensation nuclei (CCN) and giant CCN (GCCN). Initial profiles of CCN and GCCN concentrations were set to represent "clean" continental and aerosol-polluted environments, respectively. With a reduction in warm- and cold-rain processes, the polluted environment produced a longer-lived supercell with a well-defined rear flank downdraft (RFD) and relatively weak forward flank downdraft (FFD) that produced weak evaporative cooling, a weak cold-pool, and an EF-1 tornado. The clean environment produced no tornado and was less favorable for tornadogenesis. In the second ensemble, aerosol microphysical effects were put into context with those of convective available potential energy (CAPE) and low-level moisture. Simulations initialized with greater low-level moisture and higher CAPE produced significantly stronger precipitation, which resulted in greater evaporation and associated cooling, thus producing stronger cold-pools at the surface associated with both the forward- and rear-flank downdrafts. Simulations initialized with higher CCN concentrations resulted in reduced warm rain and more supercooled water aloft, creating larger anvils with less ice mass available for precipitation. These simulated supercells underwent less evaporative cooling within downdrafts and produced weaker cold-pools compared to the lower CCN simulations. Tornadogenesis was related to the size, strength, and location of the FFD- and RFD-based cold-pools. The combined influence of low-level moisture and CAPE played a considerably larger role on tornadogenesis compared to aerosol impacts. However, the aerosol effect was still evident. In both idealized model ensembles, the strongest, longest-lived tornado-like vortices were associated with warmer and weaker cold-pools, higher CAPE, and less negative buoyancy in the near-vortex environment compared to those storms that produced shorter-lived, weaker vortices. A final set of nested grid simulations were performed to evaluate dust indirect microphysical and direct radiative impacts on a severe storms outbreak that occurred during 15-16 April 2003 in Texas and Oklahoma. In one simulation, neither dust microphysical nor radiative effects were included (CTL). In a second simulation, only dust radiative effects were considered (RAD). In a third simulation, both dust radiative and indirect microphysical effects were simulated (DST), where dust was allowed to serve as CCN, GCCN, and ice nuclei (IN). Fine mode dust serving as CCN reduced warm rain formation in the DST simulation. Thus, cloud droplets were transported into the mixed phase region, enhancing… Advisors/Committee Members: Cotton, William R. (advisor), Rutledge, Steven A. (committee member), Kreidenweis, Sonia M. (committee member), Roesner, Larry A. (committee member).

Subjects/Keywords: aerosol; tornadoes; supercells; dust

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APA (6^th Edition):

Lerach, D. G. (2012). Simulating southwestern U.S. desert dust influences on severe, tornadic storms. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/67575

Chicago Manual of Style (16^th Edition):

Lerach, David Gregory. “Simulating southwestern U.S. desert dust influences on severe, tornadic storms.” 2012. Doctoral Dissertation, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/67575.

MLA Handbook (7^th Edition):

Lerach, David Gregory. “Simulating southwestern U.S. desert dust influences on severe, tornadic storms.” 2012. Web. 25 Feb 2021.

Vancouver:

Lerach DG. Simulating southwestern U.S. desert dust influences on severe, tornadic storms. [Internet] [Doctoral dissertation]. Colorado State University; 2012. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/67575.

Council of Science Editors:

Lerach DG. Simulating southwestern U.S. desert dust influences on severe, tornadic storms. [Doctoral Dissertation]. Colorado State University; 2012. Available from: http://hdl.handle.net/10217/67575

Colorado State University

7. Stuckmeyer, Elizabeth Anne. Boundary layer features observed during NAME 2004.

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

URL: http://hdl.handle.net/10217/47460

► S-Pol radar data from the North American Monsoon Experiment (NAME) are examined to investigate the characteristics of sea breezes that occurred during the North American… (more)

▼ S-Pol radar data from the North American Monsoon Experiment (NAME) are examined to investigate the characteristics of sea breezes that occurred during the North American Monsoon in the late summer of 2004, as well as their role in modulating monsoon convection. Zero degree plan position indicated (PPI) scans were examined to determine the presence of a sea breeze fine line in the S-Pol radar data. Sea breeze fine lines were typically observed over land very near the coast of the Gulf of California (GoC), and usually moved onshore around 1700-1800 UTC (11:00 AM - 12:00 PM local time), and then continued to move slowly inland on the coastal plain. The sea breezes typically moved on land and dissipated before any significant interactions with Sierra Madre Occidental (SMO) convection could occur. Fine lines varied in reflectivity strength, but were typically around 10 to 20 dBZ. Surface winds from the Estación Obispo (ETO) supersite were analyzed to confirm the presence of a shift in wind direction on days in which a fine line had been identified. Typically winds changed from light and variable to consistently out of the west or southwest. Vertical plots of S-Pol reflectivity were created to examine sea breeze structure in the vertical, but these were not found to be useful as the sea breeze signature was nearly impossible to distinguish from other boundary layer features. Horizontal structure was further investigated using wind profiler relative reflectivity, vertical velocity, and horizontal winds from the profiler located at ETO. Relative reflectivity and vertical velocity fields revealed a complex boundary layer structure on some days of repeating updrafts and downdrafts. Further examination of S-Pol PPI data revealed that these vertical motions are likely due to the presence of horizontal convective rolls. Profiler horizontal winds revealed that the depth and vertical structure of the sea breezes varied significantly from day to day, but that the height of the sea breeze is around 1 km above the ground. Sea breezes observed during NAME almost never initiated convection on their own. It is hypothesized that a weak thermal contrast between the GoC and the land leads to comparatively weak sea breezes, which don't have enough lift to trigger convection. Advisors/Committee Members: Rutledge, Steven A. (advisor), Johnson, Richard H. (committee member), Weckwerth, Tammy M., 1966- (committee member), Ramírez, Jorge A. (committee member).

Subjects/Keywords: boundary layer; sea breeze; radar; NAME

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APA (6^th Edition):

Stuckmeyer, E. A. (2011). Boundary layer features observed during NAME 2004. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/47460

Chicago Manual of Style (16^th Edition):

Stuckmeyer, Elizabeth Anne. “Boundary layer features observed during NAME 2004.” 2011. Masters Thesis, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/47460.

MLA Handbook (7^th Edition):

Stuckmeyer, Elizabeth Anne. “Boundary layer features observed during NAME 2004.” 2011. Web. 25 Feb 2021.

Vancouver:

Stuckmeyer EA. Boundary layer features observed during NAME 2004. [Internet] [Masters thesis]. Colorado State University; 2011. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/47460.

Council of Science Editors:

Stuckmeyer EA. Boundary layer features observed during NAME 2004. [Masters Thesis]. Colorado State University; 2011. Available from: http://hdl.handle.net/10217/47460

Colorado State University

8. Petković, Veljko. Improving the quality of extreme precipitation estimates using satellite passive microwave rainfall retrievals.

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

URL: http://hdl.handle.net/10217/183904

► Satellite rainfall estimates are invaluable in assessing global precipitation. As a part of the Global Precipitation Measurement (GPM) mission, a constellation of orbiting sensors, dominated… (more)

▼ Satellite rainfall estimates are invaluable in assessing global precipitation. As a part of the Global Precipitation Measurement (GPM) mission, a constellation of orbiting sensors, dominated by passive microwave imagers, provides a full coverage of the planet approximately every 2-3 hours. Several decades of development have resulted in passive microwave rainfall retrievals that are indispensable in addressing global precipitation climatology. However, this prominent achievement is often overshadowed by the retrieval's performance at finer spatial and temporal scales, where large variability in cloud morphology poses an obstacle for accurate rainfall measurements. This is especially true over land, where rainfall estimates are based on an observed mean relationship between high frequency (e.g., 89 GHz) brightness temperature (Tb) depression (i.e., the ice-scattering signature) and rainfall rate. In the first part of this study, an extreme precipitation event that caused historical flooding over south-east Europe is analyzed using the GPM constellation. Performance of the rainfall retrieval is evaluated against ground radar and gage reference. It is concluded that satellite observations fully address the temporal evolution of the event but greatly underestimate total rainfall accumulation (by factor of 2.5). A primary limitation of the rainfall algorithm is found to be its inability to recognize variability in precipitating system structure. This variability is closely related to the structure of the precipitation regime and the large-scale environment. To address this influence of rainfall physics on the overall retrieval bias, the second part of this study utilizes TRMM radar (PR) and radiometer (TMI) observations to first confirm that the Tb-to-rain-rate relationship is governed by the amount of ice in the atmospheric column. Then, using the Amazon and Central African regions as testbeds, it demonstrates that the amount of ice aloft is strongly linked to a precipitation regime. A correlation found between the large-scale environment and precipitation regimes is then further examined. Variables such as Convective Available Potential Energy (CAPE), Cloud Condensation Nuclei (CCN), wind shear, and vertical humidity profiles are found to be capable of predicting a precipitation regime and explaining up to 40% of climatological biases. Dry over moist air conditions are favorable for developing intense, well organized systems such as MCSs in West Africa and the Sahel. These systems are characterized by strong Tb depressions and above average amounts of ice aloft. As a consequence, microwave retrieval algorithms misinterpret these non-typical systems assigning them unrealistically high rainfall rates. The opposite is true in the Amazon region, where observed raining systems exhibit relatively little ice while producing high rainfall rates. Based on these findings, in the last part of the study, the GPM operational retrieval (GPROF) for the GMI sensor is modified to offer additional information on atmospheric conditions… Advisors/Committee Members: Kummerow, Christian D. (advisor), Vonder Haar, Thomas H. (committee member), Rutledge, Steven A. (committee member), Niemann, Jeffrey D. (committee member).

Subjects/Keywords: extreme; precipitation; regional bias; microwave radiometer; Bayesian retrieval; rainfall regimes

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APA (6^th Edition):

Petković, V. (2017). Improving the quality of extreme precipitation estimates using satellite passive microwave rainfall retrievals. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/183904

Chicago Manual of Style (16^th Edition):

Petković, Veljko. “Improving the quality of extreme precipitation estimates using satellite passive microwave rainfall retrievals.” 2017. Doctoral Dissertation, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/183904.

MLA Handbook (7^th Edition):

Petković, Veljko. “Improving the quality of extreme precipitation estimates using satellite passive microwave rainfall retrievals.” 2017. Web. 25 Feb 2021.

Vancouver:

Petković V. Improving the quality of extreme precipitation estimates using satellite passive microwave rainfall retrievals. [Internet] [Doctoral dissertation]. Colorado State University; 2017. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/183904.

Council of Science Editors:

Petković V. Improving the quality of extreme precipitation estimates using satellite passive microwave rainfall retrievals. [Doctoral Dissertation]. Colorado State University; 2017. Available from: http://hdl.handle.net/10217/183904

Colorado State University

9. Grant, Leah Danielle. Cold pool processes in different environments.

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

URL: http://hdl.handle.net/10217/189266

► Cold pools are localized regions of dense air near Earth's surface. They form in association with precipitating clouds in many environments ranging from moist tropical… (more)

▼ Cold pools are localized regions of dense air near Earth's surface. They form in association with precipitating clouds in many environments ranging from moist tropical to semi-arid continental conditions, and they play important roles in weather in climate. The overarching goal of this dissertation research is to improve our process-level understanding of cold pool interactions with different components of the Earth system, focusing on two key knowledge gaps: (1) interactions with Earth's surface in continental environments; and (2) interactions with organized convective systems in tropical oceanic environments. The primary goal of the first study conducted in this dissertation is to evaluate how surface sensible heat fluxes impact cold pool dissipation in dry continental environments via two pathways: (a) by directly heating the cold pool, and (b) by changing mixing rates between cold pool air and environmental air through altering turbulence intensity. Idealized 2D simulations of isolated cold pools are conducted with varying sensible heat flux formulations to determine the relative importance of these two mechanisms. The results demonstrate that the impact of sensible heat fluxes on mixing, i.e. mechanism (b), contributes most significantly to cold pool dissipation. Cold pool – land surface interactions in semi-arid continental conditions are investigated in the second study. Two questions are addressed: (1) how does the land surface respond to the cold pool; and (2) to what extent do land surface feedbacks modulate the cold pool evolution? Idealized 3D simulations of a cold pool evolving in a turbulent boundary layer are conducted to answer these questions. The land surface cools in response to the cold pool, resulting in suppressed sensible heat fluxes in the center of the cold pool. However, sensible heat fluxes are enhanced near the edge of the cold pool in association with higher wind speeds, leading to cold pool dissipation from the edge inwards. The land surface interactions are shown to strongly affect the cold pool, reducing its lifetime, size, and intensity by up to 50%. Preliminary analysis of a cold pool that was observed in northeastern Colorado on 17 May 2017 ("The Bees Day") during the C3LOUD-Ex field campaign is presented in the third study. The observed case exhibits similar environmental and cold pool characteristics to the first two numerical studies, thereby providing observational context for their hypotheses and conclusions. The objective of the fourth study presented in this dissertation is to determine the role of cold pools in organized tropical oceanic convective systems. To address this goal, two convective systems embedded in a weakly sheared cloud population approaching radiative-convective equilibrium are simulated at high resolution. The cold pools are weakened in the sensitivity tests by suppressing evaporation rates below cloud base. Both of the convective systems respond in a consistent manner as follows: (a) when cold pools are weakened, the convective intensity increases; and… Advisors/Committee Members: van den Heever, Susan C. (advisor), Randall, David A. (committee member), Rutledge, Steven A. (committee member), Niemann, Jeffrey D. (committee member).

Subjects/Keywords: convective processes; surface fluxes; turbulence; land - atmosphere interactions; cold pools; tropical convective systems

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APA (6^th Edition):

Grant, L. D. (2018). Cold pool processes in different environments. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/189266

Chicago Manual of Style (16^th Edition):

Grant, Leah Danielle. “Cold pool processes in different environments.” 2018. Doctoral Dissertation, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/189266.

MLA Handbook (7^th Edition):

Grant, Leah Danielle. “Cold pool processes in different environments.” 2018. Web. 25 Feb 2021.

Vancouver:

Grant LD. Cold pool processes in different environments. [Internet] [Doctoral dissertation]. Colorado State University; 2018. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/189266.

Council of Science Editors:

Grant LD. Cold pool processes in different environments. [Doctoral Dissertation]. Colorado State University; 2018. Available from: http://hdl.handle.net/10217/189266

Colorado State University

10. Stolz, Douglas C. Simultaneous influence of thermodynamics and aerosols on deep convection and lightning, The.

Degree: PhD, Atmospheric Science, 2016, Colorado State University

URL: http://hdl.handle.net/10217/173332

► The dissertation consists of a multi-scale investigation of the relative contributions of thermodynamics and aerosols to the observed variability of deep convective clouds in the… (more)

▼ The dissertation consists of a multi-scale investigation of the relative contributions of thermodynamics and aerosols to the observed variability of deep convective clouds in the Tropics. First, estimates of thermodynamic quantities and cloud-condensation nuclei (CCN) in the environment are attributed to convective features (CFs) observed by the Tropical Rainfall Measuring Mission (TRMM) satellite for eight years (2004-2011) between 36⁰S-36⁰N across all longitudes. The collection of simultaneous observations was analyzed in order to assess the relevance of thermodynamic and aerosol hypotheses for explaining the spatial and temporal variability of the characteristics of deep convective clouds. Specifically, the impacts of normalized convective available potential energy (NCAPE) and warm cloud depth (WCD) as well as CCN concentrations (D ≥ 40 nm) on total lightning density (TLD), average height of 30 dBZ echoes (AVGHT30), and vertical profiles of radar reflectivity (VPRR) within individual CFs are the subject of initial curiosity. The results show that TLD increased by up to 600% and AVGHT30 increased by up to 2-3 km with increasing NCAPE and CCN for fixed WCD on the global scale. The partial sensitivity of TLD/AVGHT30 to NCAPE and CCN individually are found to be comparable in magnitude, but each independent variable accounts for a fraction of the total range of variability observed in the response (i.e., when the influences of NCAPE and CCN are considered simultaneously). Both TLD and AVGHT30 vary inversely with WCD such that maxima of TLD and AVGHT30 are found for the combination of high NCAPE, high CCN, and shallower WCD. The relationship between lightning and radar reflectivity is shown to vary as a function of CCN for a fixed thermodynamic environment. Analysis of VPRRs shows that reflectivity in the mixed phase region (altitudes where temperatures are between 0⁰C and -40⁰C) is up to 5.0-5.6 dB greater for CFs in polluted environments compared to CFs in pristine environments (holding thermodynamics fixed). A statistical decomposition of the relative contributions of NCAPE, CCN, and WCD to the variability of convective intensity proxies is undertaken. Simple linear models of TLD/AVGHT30 based on the predictor set composed of NCAPE, CCN, and WCD account for appreciable portions of the variability in convective intensity (R2 ≈ 0.3-0.8) over the global domain, continents, oceans, and select regions. Furthermore, the results from the statistical analysis suggest that the simultaneous contributions from NCAPE, CCN, and WCD to the variability of convective intensity are often comparable in magnitude. There was evidence for similar relationships over even finer-scale regions [O(106 km2)], but differences in the relative prognostic ability and stability of individual regression parameters between regions/seasons were apparent. These results highlight the need to investigate the connection between statistical behavior and local meteorological variability within individual regions. Following the global and… Advisors/Committee Members: Rutledge, Steven A. (advisor), Pierce, Jeffrey R. (committee member), van den Heever, Susan C. (committee member), Reising, Steven C. (committee member).

Subjects/Keywords: convective clouds; radar; variability; lightning; aerosols; thermodynamics

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APA (6^th Edition):

Stolz, D. C. (2016). Simultaneous influence of thermodynamics and aerosols on deep convection and lightning, The. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/173332

Chicago Manual of Style (16^th Edition):

Stolz, Douglas C. “Simultaneous influence of thermodynamics and aerosols on deep convection and lightning, The.” 2016. Doctoral Dissertation, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/173332.

MLA Handbook (7^th Edition):

Stolz, Douglas C. “Simultaneous influence of thermodynamics and aerosols on deep convection and lightning, The.” 2016. Web. 25 Feb 2021.

Vancouver:

Stolz DC. Simultaneous influence of thermodynamics and aerosols on deep convection and lightning, The. [Internet] [Doctoral dissertation]. Colorado State University; 2016. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/173332.

Council of Science Editors:

Stolz DC. Simultaneous influence of thermodynamics and aerosols on deep convection and lightning, The. [Doctoral Dissertation]. Colorado State University; 2016. Available from: http://hdl.handle.net/10217/173332

Colorado State University

11. Rowe, Angela Kaye. Polarimetric radar analysis of convection observed during NAME and TiMREX, A.

Degree: PhD, Atmospheric Science, 2011, Colorado State University

URL: http://hdl.handle.net/10217/46215

► The mountainous regions of northwestern Mexico and southwestern Taiwan experience periods of intense rainfall associated with the North American and Asian monsoons, respectively, as warm,… (more)

▼ The mountainous regions of northwestern Mexico and southwestern Taiwan experience periods of intense rainfall associated with the North American and Asian monsoons, respectively, as warm, moist air is ushered onshore due to a reversal of mean low-level winds. Potentially unstable air is lifted along the steep topography, leading to convective initiation over the high peaks and adjacent foothills in both regions. In addition, an enhancement of convection in preexisting systems is observed due to interaction with the terrain, leading to localized heavy rain along the western slopes. The predictability of warm-reason rainfall in these regions is limited by the lack of understanding of the nature of these precipitating features, including the diurnal variability and elevation-dependent trends in microphysical processes. Using polarimetric data from NCAR's S-band, polarimetric radar (S-Pol), deployed during the North American Monsoon Experiment (NAME) and Terrain-influenced Monsoon Rainfall Experiment (TiMREX), individual convective elements were identified and tracked, allowing for an analysis of hydrometeor characteristics within evolving cells. Furthermore, a feature classification algorithm was applied to these datasets to compare characteristics associated with isolated convection to cells contained within organized systems. Examples of isolated cells from a range of topography during NAME revealed the presence of ZDR columns, attributed to the lofting of drops above the melting level, where subsequent freezing and growth by riming led to the production of graupel along the western slopes of the Sierra Madre Occidental (SMO) and adjacent coastal plain. Melting of large ice hydrometeors was also noted over higher terrain, leading to short-lived yet intense rainfall despite truncated warm-cloud depths compared to cells over the lower elevations. Cells embedded within mesoscale convective systems (MCSs) during NAME also displayed the combined roles of warm-rain and ice-based microphysical processes as convection organized along the terrain. In addition to enhancing precipitation along the western slopes of the SMO, melting ice contributed to the production of mesoscale outflow boundaries, which provided an additional focus mechanism for convective initiation over the lower elevations and resulted in propagation of these systems toward the coast. Intense rainfall was also observed along the Central Mountain Range (CMR) in Taiwan; however, in contrast to the systems during NAME, this enhancement occurred as MCSs moved onshore within the southwesterly flow and intercepted the CMR's steep slopes. Elevated maxima in polarimetric variables, similar to observations in convection during NAME, indicated a contribution from melting ice to rainfall at these higher elevations. Vertical profiles of ice mass, however, revealed greater amounts throughout the entire vertical depth of convection during NAME. In addition, isolated cells during TiMREX were relatively shallow compared to organized convection in both regions.… Advisors/Committee Members: Rutledge, Steven A. (advisor), Johnson, Richard H. (committee member), Van den Heever, Susan C. (committee member), Lang, Timothy James (committee member), Eykholt, Richard Eric, 1956- (committee member).

Subjects/Keywords: microphysics; radar; monsoon

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

APA (6^th Edition):

Rowe, A. K. (2011). Polarimetric radar analysis of convection observed during NAME and TiMREX, A. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/46215

Chicago Manual of Style (16^th Edition):

Rowe, Angela Kaye. “Polarimetric radar analysis of convection observed during NAME and TiMREX, A.” 2011. Doctoral Dissertation, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/46215.

MLA Handbook (7^th Edition):

Rowe, Angela Kaye. “Polarimetric radar analysis of convection observed during NAME and TiMREX, A.” 2011. Web. 25 Feb 2021.

Vancouver:

Rowe AK. Polarimetric radar analysis of convection observed during NAME and TiMREX, A. [Internet] [Doctoral dissertation]. Colorado State University; 2011. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/46215.

Council of Science Editors:

Rowe AK. Polarimetric radar analysis of convection observed during NAME and TiMREX, A. [Doctoral Dissertation]. Colorado State University; 2011. Available from: http://hdl.handle.net/10217/46215

Colorado State University

12. Beavis, Nicholas. Climatology of lightning producing large impulse charge moment changes with an emphasis on mesoscale convective systems, The.

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

URL: http://hdl.handle.net/10217/81003

► The use of both total charge moment change (CMC) and impulse charge moment change (iCMC) magnitudes to assess the potential of a cloud-to-ground (CG) lightning… (more)

▼ The use of both total charge moment change (CMC) and impulse charge moment change (iCMC) magnitudes to assess the potential of a cloud-to-ground (CG) lightning stroke to induce a mesospheric sprite has been well described in literature. However, this work has primarily been carried out on a case study basis. To complement these previous case studies, climatologies of regional, seasonal, and diurnal observations of large-iCMC discharges are presented. In this study, large-iCMC discharges for thresholds > 100 and > 300 C km in both positive and negative polarities are analyzed on a seasonal basis using density maps of 2° by 2° resolution across the conterminous U.S. using data from the Charge Moment Change Network (CMCN). Also produced were local solar time diurnal distributions in eight different regions covering the lower 48 states as well as the Atlantic Ocean, including the Gulf Stream. In addition, National Lightning Detection Network (NLDN) cloud-to-ground (CG) flash diurnal distributions were included. The seasonal maps show the predisposition of large positive iCMCs to dominate across the Northern Great Plains, with large negative iCMCs favored in the Southeastern U.S. year-round. During summer, the highest frequency of large positive iCMCs across the Upper Midwest aligns closely with the preferred tracks of nocturnal mesoscale convective systems (MCSs). As iCMC values increase above 300 C km, the maximum shifts eastward of the 100 C km maximum in the Central Plains. The Southwestern U.S. also experiences significant numbers of large-iCMC discharges in summer, presumably due to convection associated with the North American Monsoon (NAM). The Gulf Stream is active year round, with a bias towards more large positive iCMCs in winter. Diurnal distributions in the eight regions support these conclusions, with a nocturnal peak in large-iCMC discharges in the Northern Great Plains and Great Lakes, an early- to mid-afternoon peak in the Intermountain West and the Southeastern US, and a morning peak in large-iCMC discharge activity over the Atlantic Ocean. Large negative iCMCs peak earlier in time than large positive iCMCs, attributed to the maturation of large stratiform charge reservoirs after initial convective development. Results of eight case studies of Northern Great Plains MCSs using the NMQ National Radar Mosaic dataset are also presented. Thresholds described above were used to disseminate iCMC discharges within the MCSs. The radar analysis algorithm on a 5-minute radar volume basis included convective-stratiform partitioning, association of iCMCs and CGs to their respective storms, and statistical analysis on large (100-300 C km) and sprite-class (>300 C km) iCMC-producing storms. Results from these case studies indicated a strong preference of sprite-class iCMCs to be positive and located in stratiform-identified regions. A 2-3 hour delay in the maximum activity of sprite-class iCMCs after the maximum large iCMC activity was noted, and was strongly correlated with the maximum… Advisors/Committee Members: Rutledge, Steven A. (advisor), Schumacher, Russ S. (committee member), Lyons, Walter A. (committee member), Lang, Timothy J. (committee member), Eykholt, Richard E. (committee member).

Subjects/Keywords: sprite; MCS; mesoscale convective system; charge moment change; lightning

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

APA (6^th Edition):

Beavis, N. (2013). Climatology of lightning producing large impulse charge moment changes with an emphasis on mesoscale convective systems, The. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/81003

Chicago Manual of Style (16^th Edition):

Beavis, Nicholas. “Climatology of lightning producing large impulse charge moment changes with an emphasis on mesoscale convective systems, The.” 2013. Masters Thesis, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/81003.

MLA Handbook (7^th Edition):

Beavis, Nicholas. “Climatology of lightning producing large impulse charge moment changes with an emphasis on mesoscale convective systems, The.” 2013. Web. 25 Feb 2021.

Vancouver:

Beavis N. Climatology of lightning producing large impulse charge moment changes with an emphasis on mesoscale convective systems, The. [Internet] [Masters thesis]. Colorado State University; 2013. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/81003.

Council of Science Editors:

Beavis N. Climatology of lightning producing large impulse charge moment changes with an emphasis on mesoscale convective systems, The. [Masters Thesis]. Colorado State University; 2013. Available from: http://hdl.handle.net/10217/81003

Colorado State University

13. Duncan, David Ian. Exploring the limits of variational passive microwave retrievals.

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

URL: http://hdl.handle.net/10217/183906

► Passive microwave observations from satellite platforms constitute one of the most important data records of the global observing system. Operational since the late 1970s, passive… (more)

▼ Passive microwave observations from satellite platforms constitute one of the most important data records of the global observing system. Operational since the late 1970s, passive microwave data underpin climate records of precipitation, sea ice extent, water vapor, and more, and contribute significantly to numerical weather prediction via data assimilation. Detailed understanding of the observation errors in these data is key to maximizing their utility for research and operational applications alike. However, the treatment of observation errors in this data record has been lacking and somewhat divergent when considering the retrieval and data assimilation communities. In this study, some limits of passive microwave imager data are considered in light of more holistic treatment of observation errors. A variational retrieval, named the CSU 1DVAR, was developed for microwave imagers and applied to the GMI and AMSR2 sensors for ocean scenes. Via an innovative method to determine forward model error, this retrieval accounts for error covariances across all channels used in the iteration. This improves validation in more complex scenes such as high wind speed and persistently cloudy regimes. In addition, it validates on par with a benchmark dataset without any tuning to in-situ observations. The algorithm yields full posterior error diagnostics and its physical forward model is applicable to other sensors, pending intercalibration. This retrieval is used to explore the viability of retrieving parameters at the limits of the available information content from a typical microwave imager. Retrieval of warm rain, marginal sea ice, and falling snow are explored with the variational retrieval. Warm rain retrieval shows some promise, with greater sensitivity than operational GPM algorithms due to leveraging CloudSat data and accounting for drop size distribution variability. Marginal sea ice is also detected with greater sensitivity than a standard operational retrieval. These studies ultimately show that while a variational algorithm maximizes the effective signal to noise ratio of these observations, hard limitations exist due to the finite information content afforded by a typical microwave imager. Advisors/Committee Members: Kummerow, Christian D. (advisor), Boukabara, Sid-Ahmed (committee member), O'Dell, Christopher W. (committee member), Reising, Steven C. (committee member), Rutledge, Steven A. (committee member), Schumacher, Russ S. (committee member).

Subjects/Keywords: remote sensing; variational methods; satellite meteorology; passive microwave

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

APA (6^th Edition):

Duncan, D. I. (2017). Exploring the limits of variational passive microwave retrievals. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/183906

Chicago Manual of Style (16^th Edition):

Duncan, David Ian. “Exploring the limits of variational passive microwave retrievals.” 2017. Doctoral Dissertation, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/183906.

MLA Handbook (7^th Edition):

Duncan, David Ian. “Exploring the limits of variational passive microwave retrievals.” 2017. Web. 25 Feb 2021.

Vancouver:

Duncan DI. Exploring the limits of variational passive microwave retrievals. [Internet] [Doctoral dissertation]. Colorado State University; 2017. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/183906.

Council of Science Editors:

Duncan DI. Exploring the limits of variational passive microwave retrievals. [Doctoral Dissertation]. Colorado State University; 2017. Available from: http://hdl.handle.net/10217/183906

Colorado State University

14. Thompson, Elizabeth J. Tropical warm pool rainfall variability and impact on upper ocean variability throughout the Madden-Julian Oscillation.

Degree: PhD, Atmospheric Science, 2016, Colorado State University

URL: http://hdl.handle.net/10217/173341

► Heating and rain freshening often stabilize the upper tropical ocean, bringing the ocean mixed layer depth to the sea surface. Thin mixed layer depths concentrate… (more)

▼ Heating and rain freshening often stabilize the upper tropical ocean, bringing the ocean mixed layer depth to the sea surface. Thin mixed layer depths concentrate subsequent fluxes of heat, momentum, and freshwater in a thin layer. Rapid heating and cooling of the tropical sea surface is important for controlling or triggering atmospheric convection. Ocean mixed layer depth and SST variability due to rainfall events have not been as comprehensively explored as the ocean’s response to heating or momentum fluxes, but are very important to understand in the tropical warm pool where precipitation exceeds evaporation and many climate phenomena such as ENSO and the MJO (Madden Julian Oscillation) originate. The first part of the dissertation investigates tropical, oceanic convective and stratiform rainfall variability and determines how to most accurately estimate rainfall accumulation with radar from each rain type. The second, main part of the dissertation uses central Indian Ocean salinity and temperature microstructure measurements and surrounding radar-derived rainfall maps throughout two DYNAMO MJO events to determine the impact of precipitating systems on upper-ocean mixed layer depth and resulting SST variability. The ocean mixed layer was as shallow as 0-5 m during 528/1071 observation hours throughout 2 MJOs (54% of the data record). Out of 43 observation days, thirty-eight near-surface mixed layer depth events were attributed to freshwater stabilization, called rain-formed mixed layers (RFLs). Thirty other mixed layer stratification events were classified as diurnal warm layers (DWLs) due to stable temperature stratification by daytime heating. RFLs and DWLs were observed to interact in two ways: 1) RFLs fill preexisting DWLs and add to total near-surface mixed layer stratification, which occurred ten times; 2) RFLs last long enough to heat, creating a new DWL on top of the RFL, which happened nine times. These combination stratification events were responsible for the highest SST warming rates and some of the highest SSTs leading up to the most active precipitation and wind stage of the each MJO. DWLs without RFL interaction helped produce the highest SSTs in suppressed MJO conditions. As storm intensity, frequency, duration, and the ability of storms to maintain stratiform rain areas increased, RFLS became more common in the disturbed and active MJO phases. Along with the barrier layer, DWL and RFL stratification events helped suppress wind-mixing, cooling, and mixed layer deepening throughout the MJO. We hypothesize that both salinity and temperature stratification events, and their interactions, are important for controlling SST variability and therefore MJO initiation in the Indian Ocean. Most RFLs were caused by submesoscale and mesoscale convective systems with stratiform rain components and local rain accumulations above 10 mm but with winds mostly below 8 m s-1. We hypothesize that the stratiform rain components of storms helped stratify the ocean by providing weak but widespread, steady, long-lived… Advisors/Committee Members: Rutledge, Steven A. (advisor), Moum, James N. (advisor), Maloney, Eric D. (committee member), Johnson, Richard H. (committee member), Chandrasekar, V. (committee member), Fairall, Christopher W. (committee member).

Subjects/Keywords: buoyancy; rainfall; boundary layer; tropical warm pool; radar

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

APA (6^th Edition):

Thompson, E. J. (2016). Tropical warm pool rainfall variability and impact on upper ocean variability throughout the Madden-Julian Oscillation. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/173341

Chicago Manual of Style (16^th Edition):

Thompson, Elizabeth J. “Tropical warm pool rainfall variability and impact on upper ocean variability throughout the Madden-Julian Oscillation.” 2016. Doctoral Dissertation, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/173341.

MLA Handbook (7^th Edition):

Thompson, Elizabeth J. “Tropical warm pool rainfall variability and impact on upper ocean variability throughout the Madden-Julian Oscillation.” 2016. Web. 25 Feb 2021.

Vancouver:

Thompson EJ. Tropical warm pool rainfall variability and impact on upper ocean variability throughout the Madden-Julian Oscillation. [Internet] [Doctoral dissertation]. Colorado State University; 2016. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/173341.

Council of Science Editors:

Thompson EJ. Tropical warm pool rainfall variability and impact on upper ocean variability throughout the Madden-Julian Oscillation. [Doctoral Dissertation]. Colorado State University; 2016. Available from: http://hdl.handle.net/10217/173341

15. Davis, Trenton. Lightning channel locations, LNOx production, and advection in anomalous and normal polarity thunderstorms.

Degree: MS(M.S.), Atmospheric Science, 2018, Colorado State University

URL: http://hdl.handle.net/10217/189289

► Tropospheric ozone is a powerful greenhouse gas and OH precursor, thus understanding its sources is important. Its production is also widely studied in atmospheric science… (more)

▼ Tropospheric ozone is a powerful greenhouse gas and OH precursor, thus understanding its sources is important. Its production is also widely studied in atmospheric science today as global climate modelers attempt to estimate future warming within the troposphere. Nitrogen oxides (NO + NO2 = NOx), serve as a precursor to ozone production. In areas where higher concentrations of OH are present, NOx will undergo reactions to produce nitric acid, thereby shortening its lifetime and limiting the production of ozone. Due to lower concentrations of OH in the upper troposphere, NOx tends to experience a longer lifetime (on the order of days) and greater ozone production at these heights. Lightning produces an appreciable amount of NOx (a.k.a. LNOx) but the final distribution of resulting LNOx, and thus its ozone production, remains poorly understood. Therefore, it is important that this source of NOx be further investigated to improve current LNOx parameterizations. Numerical modeling methods attempt to study this issue by parameterizing the nature of lightning within thunderstorms. Often, the vertical distribution of flash channels (and LNOx) is produced according to a parameterized flash rate within a defined vertical profile and reflectivity volume threshold. The structure and intensity of thunderstorms are highly variable though, causing the location of lightning within a thunderstorm to differ from one thunderstorm to the next. Furthermore, one remaining goal of the Deep Convective Clouds and Chemistry (DC3) field campaign (May – June 2012) was to compare the lightning flash locations and contributions to upper tropospheric LNOx between storms of normal and anomalous charge polarity. To address this remaining goal, five cases with over 5600 total flashes are analyzed in detail using data from DC3, three in northern Colorado and two in northern Alabama. Lightning sources are combined into 3-dimensional (3-D) flash channels and flash channel parcels, with each parcel containing the LNOx produced by its parent flash channel. Parcels are then advected forward in time during the lifetime of each storm using 3-D wind fields produced from dual-Doppler analyses. Results reveal a greater number of flashes and flash channels within anomalous polarity thunderstorms compared to normal polarity thunderstorms at a mean initiation height around 5 km. Flashes in these storms also appear to transect areas of higher vertical velocities resulting in roughly half of flash channel parcels being advected to the upper troposphere (z > 8 km). Contrary to some assumptions, an appreciable fraction of these parcels and NOx contributions remain in the boundary layer of these storms. In the two normal polarity thunderstorm cases, flash channels tend to initiate around 8 km with roughly half of the flash channel parcels remaining near or above 8 km. While both storm types appear to transport roughly 50% of their flash channel parcels to the upper troposphere, significantly larger flash counts and total flash length in the anomalous polarity storms… Advisors/Committee Members: Rutledge, Steven A. (advisor), Barth, Mary (committee member), Fischer, Emily (committee member), Reising, Steven (committee member).

Subjects/Keywords: anomalous; LNOx; thunderstorms; lightning; advection; normal

…Alabama (NALMA). Radar observations were measured by the Colorado State University…

13 more images…

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

APA (6^th Edition):

Davis, T. (2018). Lightning channel locations, LNOx production, and advection in anomalous and normal polarity thunderstorms. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/189289

Chicago Manual of Style (16^th Edition):

Davis, Trenton. “Lightning channel locations, LNOx production, and advection in anomalous and normal polarity thunderstorms.” 2018. Masters Thesis, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/189289.

MLA Handbook (7^th Edition):

Davis, Trenton. “Lightning channel locations, LNOx production, and advection in anomalous and normal polarity thunderstorms.” 2018. Web. 25 Feb 2021.

Vancouver:

Davis T. Lightning channel locations, LNOx production, and advection in anomalous and normal polarity thunderstorms. [Internet] [Masters thesis]. Colorado State University; 2018. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/189289.

Council of Science Editors:

Davis T. Lightning channel locations, LNOx production, and advection in anomalous and normal polarity thunderstorms. [Masters Thesis]. Colorado State University; 2018. Available from: http://hdl.handle.net/10217/189289

16. Jha, Vandana. Examination of the potential impacts of dust and pollution aerosol acting as cloud nucleating aerosol on water resources in the Colorado River Basin.

Degree: PhD, Atmospheric Science, 2016, Colorado State University

URL: http://hdl.handle.net/10217/173399

► In this study we examine the cumulative effect of dust acting as cloud nucleating aerosol (cloud condensation nuclei (CCN), giant cloud condensation nuclei (GCCN), and… (more)

▼ In this study we examine the cumulative effect of dust acting as cloud nucleating aerosol (cloud condensation nuclei (CCN), giant cloud condensation nuclei (GCCN), and ice nuclei (IN)) along with anthropogenic aerosol pollution acting primarily as CCN, over the entire Colorado Rocky Mountains from the months of October to April in the year 2004-2005; the snow year. This ~6.5 months analysis provides a range of snowfall totals and variability in dust and anthropogenic aerosol pollution. The specific objectives of this research is to quantify the impacts of both dust and pollution aerosols on wintertime precipitation in the Colorado Mountains using the Regional Atmospheric Modeling System (RAMS). In general, dust enhances precipitation primarily by acting as IN, while aerosol pollution reduces water resources in the CRB via the so-called “spill-over” effect, by enhancing cloud droplet concentrations and reducing riming rates. Dust is more episodic and aerosol pollution is more pervasive throughout the winter season. Combined response to dust and aerosol pollution is a net reduction of water resources in the CRB. The question is by how much are those water resources affected? Our best estimate is that total winter-season precipitation loss for for the CRB the 2004-2005 winter season due to the combined influence of aerosol pollution and dust is 5,380,00 acre-feet of water. Sensitivity studies for different cases have also been run for the specific cases in 2004-2005 winter season to analyze the impact of changing dust and aerosol ratios on precipitation in the Colorado River Basin. The dust is varied from 3 to 10 times in the experiments and the response is found to be non monotonic and depends on various environmental factors. The sensitivity studies show that adding dust in a wet system increases precipitation when IN affects are dominant. For a relatively dry system high concentrations of dust can result in over-seeding the clouds and reductions in precipitation. However, when adding dust to a system with warmer cloud bases, the response is non-monotonical, and when CCN affects are dominant, reductions in precipitation are found. Advisors/Committee Members: Cotton, William R. (advisor), Rutledge, Steven A. (committee member), Pierce, Jeffery (committee member), Ramirez, Jorge (committee member).

Subjects/Keywords: CCN; dust; precipitation; Colorado River Basin; aerosol; IN

…Carrio, Colorado State University from an ensemble of simulations covering a range of vertical… …18 2.4.0 RAMS dynamic model setup In this study we set up the Colorado State University… …been added to read dust into RAMS. Dr. Jeffery Pierce of Colorado State University ran GEOS…

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APA (6^th Edition):

Jha, V. (2016). Examination of the potential impacts of dust and pollution aerosol acting as cloud nucleating aerosol on water resources in the Colorado River Basin. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/173399

Chicago Manual of Style (16^th Edition):

Jha, Vandana. “Examination of the potential impacts of dust and pollution aerosol acting as cloud nucleating aerosol on water resources in the Colorado River Basin.” 2016. Doctoral Dissertation, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/173399.

MLA Handbook (7^th Edition):

Jha, Vandana. “Examination of the potential impacts of dust and pollution aerosol acting as cloud nucleating aerosol on water resources in the Colorado River Basin.” 2016. Web. 25 Feb 2021.

Vancouver:

Jha V. Examination of the potential impacts of dust and pollution aerosol acting as cloud nucleating aerosol on water resources in the Colorado River Basin. [Internet] [Doctoral dissertation]. Colorado State University; 2016. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/173399.

Council of Science Editors:

Jha V. Examination of the potential impacts of dust and pollution aerosol acting as cloud nucleating aerosol on water resources in the Colorado River Basin. [Doctoral Dissertation]. Colorado State University; 2016. Available from: http://hdl.handle.net/10217/173399

17. Pereira, Luis Gustavo P. Characteristics and organization of precipitating features during NAME 2004 and their relationship to environmental conditions.

Degree: PhD, Atmospheric Science, 2008, Colorado State University

URL: http://hdl.handle.net/10217/199897

► The focus of this study is to examine the characteristics of convective precipitating features (PFs) during the 2004 North American Monsoon Experiment (NAME) and their… (more)

▼ The focus of this study is to examine the characteristics of convective precipitating features (PFs) during the 2004 North American Monsoon Experiment (NAME) and their precursor environmental conditions. The goal is to gain a better insight into the predictability and variability of warm season convective processes in the southern portion of the North American Monsoon core region. The organization and characteristics of PFs are evaluated using composite radar reflectivity images over the southern portion of the Gulf of California. The environmental conditions are assessed using satellite images and a plethora of atmospheric observational analysis maps, such as winds at multiple levels, upper-level divergence, vorticity, vertical air motion, moisture and vertical cross-sections. Our study reveals that most PFs occurred during the afternoon and evening over land, especially near the foothills of the Sierra Madre Occidental. The vast majority of the precipitating features (~95%) were small, isolated, unorganized, short-lived convective cells. Mesoscale convective systems (MCSs) made up only 5% of the PF population. Nonetheless, these large, long-lived, precipitating features were responsible for 72% of the total precipitation within the radar composite region. An analysis of the number and rainfall produced by these MCSs revealed that they were not constant from day to day, but rather, varied significantly throughout NAME. We found that MCSs were more frequent when the atmosphere is thermodynamically unstable and the wind shear or large-scale dynamics favors the development of organized convection. Lastly, we examined the synoptic conditions associated with episodes of above average MCS rainfall in the southern portion of the NAME core region. Tropical waves were found to be an essential source of moisture and instability in the region. We also found that transient upper-level inverted troughs interact with the upper-level anticyclone to produce a "North American Monsoon Jet Streak" that created favorable dynamical uplift and wind shear conditions for MCS development. Advisors/Committee Members: Rutledge, Steven A. (advisor), Johnson, Richard H. (committee member), Kummerow, Christian D. (committee member), Cifelli, Robert C. (committee member), Chandrasekar, V. (committee member).

Subjects/Keywords: Monsoons; Convection (Meteorology)

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APA (6^th Edition):

Pereira, L. G. P. (2008). Characteristics and organization of precipitating features during NAME 2004 and their relationship to environmental conditions. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/199897

Chicago Manual of Style (16^th Edition):

Pereira, Luis Gustavo P. “Characteristics and organization of precipitating features during NAME 2004 and their relationship to environmental conditions.” 2008. Doctoral Dissertation, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/199897.

MLA Handbook (7^th Edition):

Pereira, Luis Gustavo P. “Characteristics and organization of precipitating features during NAME 2004 and their relationship to environmental conditions.” 2008. Web. 25 Feb 2021.

Vancouver:

Pereira LGP. Characteristics and organization of precipitating features during NAME 2004 and their relationship to environmental conditions. [Internet] [Doctoral dissertation]. Colorado State University; 2008. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/199897.

Council of Science Editors:

Pereira LGP. Characteristics and organization of precipitating features during NAME 2004 and their relationship to environmental conditions. [Doctoral Dissertation]. Colorado State University; 2008. Available from: http://hdl.handle.net/10217/199897

Colorado State University

18. Kalb, Christina P. Cloud-to-ground lightning polarity and environmental conditions over the central United States.

Degree: MS(M.S.), Atmospheric Science, 2007, Colorado State University

URL: http://hdl.handle.net/10217/178749

► The majority of cloud-to-ground (CG) lightning across the United States lowers negative charge to the ground. However, recent studies have documented storms that produce an… (more)

Subjects/Keywords: Lightning – United States – Analysis; Thunderstorms – United States – Analysis

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APA (6^th Edition):

Kalb, C. P. (2007). Cloud-to-ground lightning polarity and environmental conditions over the central United States. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/178749

Chicago Manual of Style (16^th Edition):

Kalb, Christina P. “Cloud-to-ground lightning polarity and environmental conditions over the central United States.” 2007. Masters Thesis, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/178749.

MLA Handbook (7^th Edition):

Kalb, Christina P. “Cloud-to-ground lightning polarity and environmental conditions over the central United States.” 2007. Web. 25 Feb 2021.

Vancouver:

Kalb CP. Cloud-to-ground lightning polarity and environmental conditions over the central United States. [Internet] [Masters thesis]. Colorado State University; 2007. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/178749.

Council of Science Editors:

Kalb CP. Cloud-to-ground lightning polarity and environmental conditions over the central United States. [Masters Thesis]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/178749

Colorado State University

19. Leon Colon, Leyda V. Estimation and correction of wet ice attenuation for x-band radar.

Degree: PhD, Electrical and Computer Engineering, 2010, Colorado State University

URL: http://hdl.handle.net/10217/39323

► In the past, single polarized X-band radars were primarily used (along with S-band radars) for hail detection, first by the Russians and then later for… (more)

▼ In the past, single polarized X-band radars were primarily used (along with S-band radars) for hail detection, first by the Russians and then later for the National Hail Research Experiment (NHRE). But X-band radars were not used alone because of the large attenuation at frequencies around 10 GHz and higher, until dual-polarized radars were developed. This fact has brought attention to development and evaluation of correction techniques for rain attenuation in order to exploit the advantages of dual-polarized data. Past developed methods make use of the close relation between the differential propagation phase ΦDP and path attenuation PIA. Their use is known to be successful in rain events, but in the presence of wet ice, these methods are no longer useful because the differential propagation phase is not affected by the isotropic wet ice. This factor was the basis to develop herein two different techniques for estimating the attenuation due to rain and wet ice separately and correct for the wet ice induced attenuation. In this dissertation, two methods are investigated and evaluated. The first method uses the Surface Reference Technique (SRT) α-adjustment method to correct for the attenuation. This method was first developed for the Tropical Rainfall Measuring Mission (TRMM) precipitation radar. We assume that S-band data is un-attenuated and is used as a reference. The difference in reflectivities at the end of the beam (defined as the average of the last ten gates with 'good' data) is attributed to the total attenuation (sum of rain and any wet ice) along the propagation path. The attenuation due to the rain component, if any, is corrected for using the differential propagation phase. Then the α value in the Ah(X)wet ice-Zh(X) power law relationship (with fixed exponent β) is adjusted such that the reflectivities at S-band and the rain-corrected reflectivity at X-band at the end of the beam are forced to match. This adjusted α is used to apportion the reflectivity backwards, which assumes the α parameter is constant along the beam. Using the adjusted value, the attenuation due to wet ice is estimated separately from that of rain. This method is termed here as the SRT-modified correction method. This method has been applied to different datasets. It was evaluated in both simulated and measured radar data. Using the Regional Atmospheric Modeling System (RAMS) model a supercell was simulated by Professor's Cotton's group at Colorado State University (CSU). A radar emulator was used to simulate radar measurements from this supercell at both X-band and S-bands. Results showed good agreement of both corrected reflectivity profiles and wet ice specific attenuation estimation. A dataset from the International H2O Project (IHOP) that had rain mixed with wet ice particles (mixed phase region) was analyzed too. It showed good agreement also, when comparing profiles; moreover wet ice attenuation contours showed agreement with high values of reflectivity as expected in wet ice regions. Data collected by the Center for Adaptive… Advisors/Committee Members: Bringi, V. N., 1949- (advisor), Chandrasekar, V. (committee member), Reising, Steven C. (committee member), Rutledge, Steven A. (committee member).

Subjects/Keywords: specific attenuation; radars; correction; x-band; wet ice; Radar meteorology – Research; Microwaves – Attenuation; Doppler radar; Weather forecasting

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

APA (6^th Edition):

Leon Colon, L. V. (2010). Estimation and correction of wet ice attenuation for x-band radar. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/39323

Chicago Manual of Style (16^th Edition):

Leon Colon, Leyda V. “Estimation and correction of wet ice attenuation for x-band radar.” 2010. Doctoral Dissertation, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/39323.

MLA Handbook (7^th Edition):

Leon Colon, Leyda V. “Estimation and correction of wet ice attenuation for x-band radar.” 2010. Web. 25 Feb 2021.

Vancouver:

Leon Colon LV. Estimation and correction of wet ice attenuation for x-band radar. [Internet] [Doctoral dissertation]. Colorado State University; 2010. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/39323.

Council of Science Editors:

Leon Colon LV. Estimation and correction of wet ice attenuation for x-band radar. [Doctoral Dissertation]. Colorado State University; 2010. Available from: http://hdl.handle.net/10217/39323

Colorado State University

20. Munchak, Stephen Joseph. Method to combine spaceborne radar and radiometric observations of precipitation, A.

Degree: PhD, Atmospheric Science, 2010, Colorado State University

URL: http://hdl.handle.net/10217/44767

► This dissertation describes the development and application of a combined radar-radiometer rainfall retrieval algorithm for the Tropical Rainfall Measuring Mission (TRMM) satellite. A retrieval framework… (more)

▼ This dissertation describes the development and application of a combined radar-radiometer rainfall retrieval algorithm for the Tropical Rainfall Measuring Mission (TRMM) satellite. A retrieval framework based upon optimal estimation theory is proposed wherein three parameters describing the raindrop size distribution (DSD), ice particle size distribution (PSD), and cloud water path (cLWP) are retrieved for each radar profile. The retrieved rainfall rate is found to be strongly sensitive to the a priori constraints in DSD and cLWP; thus, these parameters are tuned to match polarimetric radar estimates of rainfall near Kwajalein, Republic of Marshall Islands. An independent validation against gauge-tuned radar rainfall estimates at Melbourne, FL shows agreement within 2% which exceeds previous algorithms' ability to match rainfall at these two sites. The algorithm is then applied to two years of TRMM data over oceans to determine the sources of DSD variability. Three correlated sets of variables representing storm dynamics, background environment, and cloud microphysics are found to account for approximately 50% of the variability in the absolute and reflectivity-normalized median drop size. Structures of radar reflectivity are also identified and related to drop size, with these relationships being confirmed by ground-based polarimetric radar data from the North American Monsoon Experiment (NAME). Regional patterns of DSD and the sources of variability identified herein are also shown to be consistent with previous work documenting regional DSD properties. In particular, mid-latitude regions and tropical regions near land tend to have larger drops for a given reflectivity, whereas the smallest drops are found in the eastern Pacific Intertropical Convergence Zone. Due to properties of the DSD and rain water/cloud water partitioning that change with column water vapor, it is shown that increases in water vapor in a global warming scenario could lead to slight (1%) underestimates of a rainfall trends by radar but larger overestimates (5%) by radiometer algorithms. Further analyses are performed to compare tropical oceanic mean rainfall rates between the combined algorithm and other sources. The combined algorithm is 15% higher than the version 6 of the 2A25 radar-only algorithm and 6.6% higher than the Global Precipitation Climatology Project (GPCP) estimate for the same time-space domain. Despite being higher than these two sources, the combined total is not inconsistent with estimates of the other components of the energy budget given their uncertainties. Advisors/Committee Members: Kummerow, Christian Detlef (advisor), Chandrasekhar, V. (committee member), Rutledge, Steven A. (committee member), Stephens, Graeme L., 1952- (committee member).

Subjects/Keywords: Tropical Rainfall Measuring Mission; TRMM; rain; radiometer; radar; precipitation; multi-sensor; Precipitation (Meteorology) – Measurement; Radiometers; Rain and rainfall – Measurement

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

APA (6^th Edition):

Munchak, S. J. (2010). Method to combine spaceborne radar and radiometric observations of precipitation, A. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/44767

Chicago Manual of Style (16^th Edition):

Munchak, Stephen Joseph. “Method to combine spaceborne radar and radiometric observations of precipitation, A.” 2010. Doctoral Dissertation, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/44767.

MLA Handbook (7^th Edition):

Munchak, Stephen Joseph. “Method to combine spaceborne radar and radiometric observations of precipitation, A.” 2010. Web. 25 Feb 2021.

Vancouver:

Munchak SJ. Method to combine spaceborne radar and radiometric observations of precipitation, A. [Internet] [Doctoral dissertation]. Colorado State University; 2010. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/44767.

Council of Science Editors:

Munchak SJ. Method to combine spaceborne radar and radiometric observations of precipitation, A. [Doctoral Dissertation]. Colorado State University; 2010. Available from: http://hdl.handle.net/10217/44767

Colorado State University

21. Sahoo, Swaroop. Retrieval techniques and information content analysis to improve remote sensing of atmospheric water vapor, liquid water and temperature from ground-based microwave radiometer measurements.

Degree: PhD, Electrical and Computer Engineering, 2015, Colorado State University

URL: http://hdl.handle.net/10217/166870

To view the abstract, please see the full text of the document. Advisors/Committee Members: Reising, Steven C. (advisor), Notaros, Branislav M. (committee member), Vivekanandan, Jothiram (committee member), Rutledge, Steven A. (committee member).

Subjects/Keywords: radiometry; temperature; atmospheric measurements; water vapor; remote sensing

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

APA (6^th Edition):

Sahoo, S. (2015). Retrieval techniques and information content analysis to improve remote sensing of atmospheric water vapor, liquid water and temperature from ground-based microwave radiometer measurements. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/166870

Chicago Manual of Style (16^th Edition):

Sahoo, Swaroop. “Retrieval techniques and information content analysis to improve remote sensing of atmospheric water vapor, liquid water and temperature from ground-based microwave radiometer measurements.” 2015. Doctoral Dissertation, Colorado State University. Accessed February 25, 2021. http://hdl.handle.net/10217/166870.

MLA Handbook (7^th Edition):

Sahoo, Swaroop. “Retrieval techniques and information content analysis to improve remote sensing of atmospheric water vapor, liquid water and temperature from ground-based microwave radiometer measurements.” 2015. Web. 25 Feb 2021.

Vancouver:

Sahoo S. Retrieval techniques and information content analysis to improve remote sensing of atmospheric water vapor, liquid water and temperature from ground-based microwave radiometer measurements. [Internet] [Doctoral dissertation]. Colorado State University; 2015. [cited 2021 Feb 25]. Available from: http://hdl.handle.net/10217/166870.

Council of Science Editors:

Sahoo S. Retrieval techniques and information content analysis to improve remote sensing of atmospheric water vapor, liquid water and temperature from ground-based microwave radiometer measurements. [Doctoral Dissertation]. Colorado State University; 2015. Available from: http://hdl.handle.net/10217/166870

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