+publisher:"University of Oklahoma" +contributor:("Chilson, Phillip")

University of Oklahoma

1. Grams, Heather. Identification of Enhanced Rainfall Rates Using the Near-Storm Environment for Radar Precipitation Estimates.

Degree: PhD, 2012, University of Oklahoma

URL: http://hdl.handle.net/11244/318950

► Overall, the probability-based precipitation type delineation scheme improved hourly rainfall accumulations for three independent cases tested when compared to both the legacy rainfall product from… (more)

Subjects/Keywords: Rain and rainfall – Measurement; Precipitation (Meteorology); Flood forecasting; Radar meteorology; Polarimetry

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APA (6^th Edition):

Grams, H. (2012). Identification of Enhanced Rainfall Rates Using the Near-Storm Environment for Radar Precipitation Estimates. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/318950

Chicago Manual of Style (16^th Edition):

Grams, Heather. “Identification of Enhanced Rainfall Rates Using the Near-Storm Environment for Radar Precipitation Estimates.” 2012. Doctoral Dissertation, University of Oklahoma. Accessed March 05, 2021. http://hdl.handle.net/11244/318950.

MLA Handbook (7^th Edition):

Grams, Heather. “Identification of Enhanced Rainfall Rates Using the Near-Storm Environment for Radar Precipitation Estimates.” 2012. Web. 05 Mar 2021.

Vancouver:

Grams H. Identification of Enhanced Rainfall Rates Using the Near-Storm Environment for Radar Precipitation Estimates. [Internet] [Doctoral dissertation]. University of Oklahoma; 2012. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/11244/318950.

Council of Science Editors:

Grams H. Identification of Enhanced Rainfall Rates Using the Near-Storm Environment for Radar Precipitation Estimates. [Doctoral Dissertation]. University of Oklahoma; 2012. Available from: http://hdl.handle.net/11244/318950

University of Oklahoma

2. Scipión, Danny Eddy. Characterization of the convective boundary layer through a combination of large-eddy simulations and a radar simulator.

Degree: PhD, 2011, University of Oklahoma

URL: http://hdl.handle.net/11244/318883

► It has been observed that during the presence of strong horizontal shear of vertical velocity, the estimates of the horizontal wind fields are biased. This… (more)

Subjects/Keywords: Boundary layer (Meteorology); Eddies – Simulation; Eddies – Mathematical models; Atmospheric circulation – Computer simulation

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APA (6^th Edition):

Scipión, D. E. (2011). Characterization of the convective boundary layer through a combination of large-eddy simulations and a radar simulator. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/318883

Chicago Manual of Style (16^th Edition):

Scipión, Danny Eddy. “Characterization of the convective boundary layer through a combination of large-eddy simulations and a radar simulator.” 2011. Doctoral Dissertation, University of Oklahoma. Accessed March 05, 2021. http://hdl.handle.net/11244/318883.

MLA Handbook (7^th Edition):

Scipión, Danny Eddy. “Characterization of the convective boundary layer through a combination of large-eddy simulations and a radar simulator.” 2011. Web. 05 Mar 2021.

Vancouver:

Scipión DE. Characterization of the convective boundary layer through a combination of large-eddy simulations and a radar simulator. [Internet] [Doctoral dissertation]. University of Oklahoma; 2011. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/11244/318883.

Council of Science Editors:

Scipión DE. Characterization of the convective boundary layer through a combination of large-eddy simulations and a radar simulator. [Doctoral Dissertation]. University of Oklahoma; 2011. Available from: http://hdl.handle.net/11244/318883

University of Oklahoma

3. Roeder, Diane. From individuals to environment: the relative roles of morphology, flight, density, synchrony, habitat structure, and weather on extra-pair paternity.

Degree: PhD, 2016, University of Oklahoma

URL: http://hdl.handle.net/11244/44930

► Reproductive success is driven in large part by the mating system of a species, which ultimately determines patterns of gene transmission across generations. In species… (more)

▼ Reproductive success is driven in large part by the mating system of a species, which ultimately determines patterns of gene transmission across generations. In species with socially monogamous mating systems, an important component of reproductive success is extra-pair paternity (EPP), when males obtain fertilizations outside of their social pairing. While social monogamy is rare in most taxa, it is the most common mating system of birds and >75% of species have appreciable rates of EPP. Although, the distribution of EPP in birds has a large phylogenetic component, there is a great deal of variability across populations, suggesting contemporary constraints on extra-pair behavior. Given the prevalence of EPP in birds, it is important that we understand how these factors interact to drive or constrain the opportunity for EPP, and thus sexual selection and the genetic contribution of individuals to the next generation. In this dissertation, I examined the distribution of EPP between the two main passerine suborders, and then attempted to elucidate the influence of individual, ecological, and environment characteristics individually, and finally, in combination, on the probability of EPP in nests of a savannah oscine passerine, the Scissor-tailed Flycatcher (Tyrannus forficatus). In Chapter 1, I compared EPP rates in commonly studied oscine species (Suborder Passeri) to those in the less frequently studied suboscines (Suborder Tyranni). I found similar EPP rates between the suborders and suggest that generalizations from oscines may be extended to this group. In addition, I used molecular techniques to investigate EPP rates in the suboscine Scissor-tailed Flycatcher and found that the population under study had high rates of EPP compared to other passerine species, with 73% of nests containing extra-pair young and 59% of young resulting from extra-pair copulations. In Chapter 2, I used this species to examine whether individual characteristics influence the distribution of EPP in the population. Males in good body condition and with a high degree of tail symmetry, which may have indicated individual quality, were cuckolded infrequently. Females may have been more faithful to high quality males or, alternately, these males may have been better able to continuously guard their mates from extra-pair copulation (EPC) attempts. In Chapter 3, I moved beyond the individual to ask how timing of nesting, breeding density, and breeding synchrony influence the frequency with which individuals interact, and thus rates of EPP. I found that EPP was negatively influenced by the distance to neighbors with synchronously fertile mates and that cuckolded males and their cuckolders were not mate-guarding concurrently. These results suggest that males with fertile mates must invest their time into mate-guarding to assure paternity in their own nests, while males not mate-guarding are free to seek EPCs. I also investigated how habitat structure on breeding territories influenced EPP. I found that EPP declined with an increase… Advisors/Committee Members: Patten, Michael (advisor), Kelly, Jeffrey (committee member), Weider, Lawrence (committee member), Murphy, Michael (committee member), Chilson, Phillip (committee member).

Subjects/Keywords: Behavior; Extra-pair paternity; Bird; Ecology

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APA (6^th Edition):

Roeder, D. (2016). From individuals to environment: the relative roles of morphology, flight, density, synchrony, habitat structure, and weather on extra-pair paternity. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/44930

Chicago Manual of Style (16^th Edition):

Roeder, Diane. “From individuals to environment: the relative roles of morphology, flight, density, synchrony, habitat structure, and weather on extra-pair paternity.” 2016. Doctoral Dissertation, University of Oklahoma. Accessed March 05, 2021. http://hdl.handle.net/11244/44930.

MLA Handbook (7^th Edition):

Roeder, Diane. “From individuals to environment: the relative roles of morphology, flight, density, synchrony, habitat structure, and weather on extra-pair paternity.” 2016. Web. 05 Mar 2021.

Vancouver:

Roeder D. From individuals to environment: the relative roles of morphology, flight, density, synchrony, habitat structure, and weather on extra-pair paternity. [Internet] [Doctoral dissertation]. University of Oklahoma; 2016. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/11244/44930.

Council of Science Editors:

Roeder D. From individuals to environment: the relative roles of morphology, flight, density, synchrony, habitat structure, and weather on extra-pair paternity. [Doctoral Dissertation]. University of Oklahoma; 2016. Available from: http://hdl.handle.net/11244/44930

University of Oklahoma

4. Bonin, Timothy. Nocturnal Boundary Layer and Low-level Jet Characteristics under Different Turbulent Regimes.

Degree: PhD, 2015, University of Oklahoma

URL: http://hdl.handle.net/11244/14623

► The intensity, extent, and continuity of turbulence in the nocturnal stable boundary layer (SBL) is governed by many interacting processes and features. Generally, SBLs can… (more)

▼ The intensity, extent, and continuity of turbulence in the nocturnal stable boundary layer (SBL) is governed by many interacting processes and features. Generally, SBLs can be grouped into two broad categories: weakly stable and very stable. While the weakly SBL is relatively well understood and can be described by Monin-Obukhov similarity theory or other local scaling laws, the very SBL is difficult to characterize and parameterize. It is also difficult to predict which type of SBL will form nocturnally as differentiating characteristics of the two regimes are not well-known. Furthermore, nocturnal low-level jets (LLJs) often form around sunset, particularly in the Great Plains region of the United States, and generally interact with the nocturnal SBL. These relationships between LLJs and the SBL are currently not well-understood. To characterize turbulence within the SBL, vertical velocity variances estimated from Doppler lidar (DL) observations are used, which first need to be validated. To accomplish this, DL-derived values of vertical velocity variance are directly compared with those from sonic anemometer observations installed on a 300-m tower during the Lower Atmospheric Thermodynamics and Turbulence Experiment (LATTE), which was conducted in February – April 2014 at the Boulder Atmospheric Observatory . An autocovariance method of removing noise from the DL observations is used, which is shown to improve measurements of vertical velocity variance. In addition to removing noise, this method can also correct for underestimates of variance due to time and volume averaging of the DL. Generally, the DL-derived variance values tend to agree closely with those from the sonic anemometers after the autocovariance correction is applied. To investigate the SBL in detail, Doppler lidar, sonic anemometer, Atmospheric Emitted Radiance Interferometer (AERI), and radiosonde measurements that were collected during the Lower Atmospheric Boundary Layer Experiment (LABLE-I) are analyzed. LABLE-I was a multi-institutional field campaign that took place from 18 September to 13 November 2012 at the Southern Great Plains site in north central Oklahoma. During the experiment, LLJs were frequently observed and interacted with both weakly and very stable SBLs. Within the weakly stable boundary layer, turbulence tended to be generated at the surface and transported upward, and no strong surface-based inversion formed overnight. When a strongly stable boundary layer formed, mixing was either generated near a LLJ or at the surface and remained very weak overnight. On these nights, a strong surface based inversion formed and slowly grew throughout the night. LLJs also evolved differently depending on if a weakly or strongly SBL formed. With a strongly SBL, LLJs tended to increase in both strength and height overnight, often corresponding to a gradual increase in synoptic-scale forcing. LLJs that occurred with a weakly SBL generally remained constant in height overnight, and reached a peak in strength around… Advisors/Committee Members: Klein, Petra (advisor), Chilson, Phillip (advisor), Shapiro, Alan (committee member), Turner, David (committee member), Miller, David (committee member).

Subjects/Keywords: Low-level jet; Stable boundary layer; Doppler lidar

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

APA (6^th Edition):

Bonin, T. (2015). Nocturnal Boundary Layer and Low-level Jet Characteristics under Different Turbulent Regimes. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/14623

Chicago Manual of Style (16^th Edition):

Bonin, Timothy. “Nocturnal Boundary Layer and Low-level Jet Characteristics under Different Turbulent Regimes.” 2015. Doctoral Dissertation, University of Oklahoma. Accessed March 05, 2021. http://hdl.handle.net/11244/14623.

MLA Handbook (7^th Edition):

Bonin, Timothy. “Nocturnal Boundary Layer and Low-level Jet Characteristics under Different Turbulent Regimes.” 2015. Web. 05 Mar 2021.

Vancouver:

Bonin T. Nocturnal Boundary Layer and Low-level Jet Characteristics under Different Turbulent Regimes. [Internet] [Doctoral dissertation]. University of Oklahoma; 2015. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/11244/14623.

Council of Science Editors:

Bonin T. Nocturnal Boundary Layer and Low-level Jet Characteristics under Different Turbulent Regimes. [Doctoral Dissertation]. University of Oklahoma; 2015. Available from: http://hdl.handle.net/11244/14623

University of Oklahoma

5. Arms, Sean. Interactions Between Coherent Structures and the Urban Canopy Layer.

Degree: PhD, 2014, University of Oklahoma

URL: http://hdl.handle.net/11244/13872

► The focus of this dissertation research is to gain further insight into the interaction of coherent structures and the urban canopy layer (CS-UCL interactions). There… (more)

▼ The focus of this dissertation research is to gain further insight into the interaction of coherent structures and the urban canopy layer (CS-UCL interactions). There is a growing body of evidence that suggests that periods of strong turbulence transport across the urban canopy layer are associated with larger scale coherent structures, particularly low speed streaks or low momentum regions. A framework for the analysis of CS-UCL interactions at full-scale is constructed through the interrogation of Direct Numerical Simulation output. A classification scheme based on a new parameter, the low momentum region index (LMRi), is developed which can identify three types of periods of interaction in the DNS output: CS-UCL interaction, transitional, and non-interaction periods. Based on this CS-UCL interaction classification scheme, depictions of flow behavior and turbulence characteristics are created for the three interaction period types using conditional analysis. These conditional views improve upon the most advanced conceptual model of CS-UCL interactions by including the flow inside the canyon. These conditional views also offer a chance to study how CS-UCL interactions might manifest in full-scale datasets, which leads to a set of characteristic markers of the CS-UCL interaction from the point of view of a stationary observation point. The most commonly used full-scale techniques for analyzing the impact of coherent structures, the quadrant analysis and wavelet analysis methods, are tested using simulated time series data from the DNS output. It is found that with some modifications, these techniques can be used to detect when low momentum region driven CS-UCL interactions occur within the modeled environment. The modified techniques are then applied to a dataset collected at the Cross Center, located on the campus of the University of Oklahoma. Conditional profiles are constructed to assess whether the characteristic markers found in the DNS output manifest at full-scale. It is found that both the modified quadrant analysis and modified wavelet analysis techniques pick up on the same phenomena, demonstrating that this is the case. It is suggested that these modified techniques be used in other urban canopy layer studies to see if the same characteristic profiles and flow patterns are present. Advisors/Committee Members: Klein, Petra (advisor), Chilson, Phillip (committee member), Fedorovich, Evgeni (committee member), Shapiro, Alan (committee member), Tarhule, Andover (committee member).

Subjects/Keywords: Coherent Structures Turbulence

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APA (6^th Edition):

Arms, S. (2014). Interactions Between Coherent Structures and the Urban Canopy Layer. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/13872

Chicago Manual of Style (16^th Edition):

Arms, Sean. “Interactions Between Coherent Structures and the Urban Canopy Layer.” 2014. Doctoral Dissertation, University of Oklahoma. Accessed March 05, 2021. http://hdl.handle.net/11244/13872.

MLA Handbook (7^th Edition):

Arms, Sean. “Interactions Between Coherent Structures and the Urban Canopy Layer.” 2014. Web. 05 Mar 2021.

Vancouver:

Arms S. Interactions Between Coherent Structures and the Urban Canopy Layer. [Internet] [Doctoral dissertation]. University of Oklahoma; 2014. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/11244/13872.

Council of Science Editors:

Arms S. Interactions Between Coherent Structures and the Urban Canopy Layer. [Doctoral Dissertation]. University of Oklahoma; 2014. Available from: http://hdl.handle.net/11244/13872

University of Oklahoma

6. Wainwright, Charlotte Elizabeth. Development and validation of a sodar simulator for atmospheric boundary layer characterization.

Degree: PhD, 2014, University of Oklahoma

URL: http://hdl.handle.net/11244/10427

► A sodar simulator capable of producing time-series data emulating sodar signals has been developed and tested. The atmospheric elds used to populate the sodar simulator… (more)

▼ A sodar simulator capable of producing time-series data emulating sodar signals has been developed and tested. The atmospheric elds used to populate the sodar simulator are taken from output of a large eddy simulation code. The characteristics of the sodar (number of beams, azimuth and zenith angles of the beams, beamwidth, transmit frequency, range resolution, etc.) are de ned by the user to allow evaluation of and comparison with existing systems. The range of the re ected acoustic signal is calculated based on a temperature-dependent speed of sound. Realistic acoustic background noise is simulated using ltered white noise. The raw acoustic time-series data are processed using a Fourier transform to yield acoustic Doppler spectra, from which the radial velocities are calculated. The design of the simulator allows for the testing of and comparison between various signal-processing techniques and averaging periods. Several di erent methods for validating the results of the time-series sodar simulator are presented, including validation of the derived wind speeds against a simulated instrumented tower and a moment sodar simulator, which evaluates the wind components using the radial velocities measured by the sodar beams, and as such includes the e ects of the DBS technique. The results of the sodar simulator are also used to evaluate vertical pro les of the structure function parameter for temperature, and these pro les are compared against those derived from a simulated unmanned aerial system, and evaluated from the large eddy simulation output directly. Two example cases are presented of populating the sodar simulator with large eddy simulation data representative of one developing and one fully developed convective boundary layer, and a third example case using large-eddy simulation output of a stable boundary layer. Advisors/Committee Members: Chilson, Phillip (advisor), Palmer, Robert (advisor), Klein, Petra (committee member), Fedorovich, Evgeni (committee member), Kelly, Jeffrey (committee member).

Subjects/Keywords: Environmental Sciences.

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APA (6^th Edition):

Wainwright, C. E. (2014). Development and validation of a sodar simulator for atmospheric boundary layer characterization. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/10427

Chicago Manual of Style (16^th Edition):

Wainwright, Charlotte Elizabeth. “Development and validation of a sodar simulator for atmospheric boundary layer characterization.” 2014. Doctoral Dissertation, University of Oklahoma. Accessed March 05, 2021. http://hdl.handle.net/11244/10427.

MLA Handbook (7^th Edition):

Wainwright, Charlotte Elizabeth. “Development and validation of a sodar simulator for atmospheric boundary layer characterization.” 2014. Web. 05 Mar 2021.

Vancouver:

Wainwright CE. Development and validation of a sodar simulator for atmospheric boundary layer characterization. [Internet] [Doctoral dissertation]. University of Oklahoma; 2014. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/11244/10427.

Council of Science Editors:

Wainwright CE. Development and validation of a sodar simulator for atmospheric boundary layer characterization. [Doctoral Dissertation]. University of Oklahoma; 2014. Available from: http://hdl.handle.net/11244/10427

University of Oklahoma

7. Griffin, Casey. Polarimetric and Rapid-Scan Radar Observations of Tornadoes.

Degree: PhD, 2019, University of Oklahoma

URL: http://hdl.handle.net/11244/320424

► Tornadoes are capable of lofting large pieces of debris that present irregular shapes, near-random orientations, and a wide range of dielectric constants to polarimetric radars.… (more)

▼ Tornadoes are capable of lofting large pieces of debris that present irregular shapes, near-random orientations, and a wide range of dielectric constants to polarimetric radars. While ties between tornadic debris signature (TDS) characteristics and tornado- and storm-scale kinematic processes have been speculated upon or investigated using photogrammetry and single-Doppler analyses, little work has been done to relate the three-dimensional wind eld to TDS characteristics and behavior. Additionally a knowledge gap in larger-scale transport and sedimentation of debris exists within the literature. This study utilizes data collected by the University of Oklahoma's Advanced Radar Research Center's OU-PRIME C-band radar as well as KTLX and KOUN WSR-88D S-band radars to study three tornadoes that occurred in Central Oklahoma on 10 May 2010. The relationship between polarimetric and kinematic variables are interrogated revealing an instance where large tornado subvortices were associated with comparatively high reflectivity, low correlation coefficient, and were surrounded by negative differential reflectivity. Comparisons of the polarimetric characteristics of two tornadoes interacting with similar land cover but with different intensities are documented. Also, the storm-scale sedimentation of debris within the supercell is investigated revealing a novel observation of TDS rotation and elongation with height. Additionally, a novel dual-wavelength comparison of debris within the tornado to debris in the near-tornado environment is presented revealing larger dual-wavelength differences in polarimetric variables for debris within the tornado and increasingly similar inner and out debris characteristics as height increases. While new insight into the behavior of tornadic debris is elucidated in this study, tornadoes themselves evolve on much shorter timescales than what can be resolved by traditional, mechanically steered radars. In order to illustrate the benefit of rapid-scan radars for the study of tornado evolution and to motivate future rapid-scan polarimetric radar observations of tornadoes and debris, high-temporal resolution observations of the 27 May 2015 Canadian, Texas, tornado collected by the Atmospheric Imaging Radar (AIR) are presented. A 10-s resolution time-height investigation of vortex tilt and differential velocity ( V) is presented and illustrates an instance of upward vortex intensification as well as downward tornado decay. Changes in tornado intensity over periods of less than 30 s coincided with rapid changes in tornado diameter. At least two small-scale vortices were observed being shed from the tornado during a brief weakening period. A persistent layer of vortex tilt was observed near the level of free convection, which separated two layers with contrasting modes of tornado decay. Finally, the vertical cross-correlation of vortex intensity reveals that apart from the brief instances of upward vortex intensification and downward decay, tornado intensity was highly correlated throughout the… Advisors/Committee Members: Palmer, Robert (advisor), Bodine, David (advisor), Fulton, Caleb (committee member), Zhang, Guifu (committee member), Chilson, Phillip (committee member).

Subjects/Keywords: Weather Radar; Tornado; Debris; Supercell Thunderstorm

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APA (6^th Edition):

Griffin, C. (2019). Polarimetric and Rapid-Scan Radar Observations of Tornadoes. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/320424

Chicago Manual of Style (16^th Edition):

Griffin, Casey. “Polarimetric and Rapid-Scan Radar Observations of Tornadoes.” 2019. Doctoral Dissertation, University of Oklahoma. Accessed March 05, 2021. http://hdl.handle.net/11244/320424.

MLA Handbook (7^th Edition):

Griffin, Casey. “Polarimetric and Rapid-Scan Radar Observations of Tornadoes.” 2019. Web. 05 Mar 2021.

Vancouver:

Griffin C. Polarimetric and Rapid-Scan Radar Observations of Tornadoes. [Internet] [Doctoral dissertation]. University of Oklahoma; 2019. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/11244/320424.

Council of Science Editors:

Griffin C. Polarimetric and Rapid-Scan Radar Observations of Tornadoes. [Doctoral Dissertation]. University of Oklahoma; 2019. Available from: http://hdl.handle.net/11244/320424

University of Oklahoma

8. Griffin, Erica. A Polarimetric and Microphysical Investigation of Winter Storms.

Degree: PhD, 2018, University of Oklahoma

URL: http://hdl.handle.net/11244/316762

► The U.S. WSR-88D network has been upgraded to polarimetric capabilities, providing dual-polarization data for regions of the country never before sampled by polarimetric radar and… (more)

▼ The U.S. WSR-88D network has been upgraded to polarimetric capabilities, providing dual-polarization data for regions of the country never before sampled by polarimetric radar and allowing for an unprecedented view into the ice microphysical processes within winter precipitation. As the polarimetric data became available, a database was compiled, consisting of thousands of hours of polarimetric observations in a wide variety of winter precipitation events and exhibiting several intriguing and repetitive polarimetric signatures. Understanding what these polarimetric signatures reveal about different microphysical processes is crucial for improving their representation in numerical weather prediction models and quantitative precipitation estimation algorithms, as well as for better understanding precipitation formation and evolution throughout the depth of a cloud, ultimately improving winter weather forecasting. This study first investigates the evolution and nature of intriguing and previously undocumented polarimetric signatures observed during the historic 8-9 February 2013 Northeast blizzard, and examines them in light of the thermodynamic environment within which they developed and the apparent microphysical processes that were active when they appeared. A more climatological and quantitative analysis is then conducted using a new quasi-vertical profile (QVP) methodology to investigate the microphysical evolution and significance of polarimetric signatures and their statistical correlations in the dendritic growth layer (DGL), at the tops of clouds, and near and within the melting layer (ML) in a selection of winter events. A statistical polarimetric model of the ML is introduced and a new method to estimate KDP in the ML is used to present the first reliable QVP statistics of KDP in the ML at S band. Advisors/Committee Members: Schuur, Terry (advisor), Chilson, Phillip (advisor), Biggerstaff, Michael (committee member), Zhang, Guifu (committee member), Engel, Michael (committee member).

Subjects/Keywords: Polarimetric radar; Ice microphysics; Winter storms; Quasi-Vertical Profiles

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

APA (6^th Edition):

Griffin, E. (2018). A Polarimetric and Microphysical Investigation of Winter Storms. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/316762

Chicago Manual of Style (16^th Edition):

Griffin, Erica. “A Polarimetric and Microphysical Investigation of Winter Storms.” 2018. Doctoral Dissertation, University of Oklahoma. Accessed March 05, 2021. http://hdl.handle.net/11244/316762.

MLA Handbook (7^th Edition):

Griffin, Erica. “A Polarimetric and Microphysical Investigation of Winter Storms.” 2018. Web. 05 Mar 2021.

Vancouver:

Griffin E. A Polarimetric and Microphysical Investigation of Winter Storms. [Internet] [Doctoral dissertation]. University of Oklahoma; 2018. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/11244/316762.

Council of Science Editors:

Griffin E. A Polarimetric and Microphysical Investigation of Winter Storms. [Doctoral Dissertation]. University of Oklahoma; 2018. Available from: http://hdl.handle.net/11244/316762

University of Oklahoma

9. Umeyama Matsumoto, Arturo. Unmanned Aerial Vehicle-based Far-Field Antenna Characterization System for Polarimetric Weather Radars.

Degree: PhD, 2020, University of Oklahoma

URL: http://hdl.handle.net/11244/326678

► The use of phased array radars for the US weather radar network (NEXRAD) has been proposed in lieu of the current mechanically steered dish-based systems,… (more)

▼ The use of phased array radars for the US weather radar network (NEXRAD) has been proposed in lieu of the current mechanically steered dish-based systems, owing to its many attractive features, e.g., electronic steering and fast update rates, and others. Scatterer identification (hydrometeors and non-hydrometeors), accurate estimation of rainfall rates, and determination of propagation effects is possible in weather radars through polarimetry. However, the existence of cross-polarization, and co-polarization mismatch in the H- and V-polarization radiation patterns introduces biases in the polarimetric weather radar products, which can adversely affect the accuracy of the estimates of byproducts, thus imposing strict antenna requirements on the co-polarization mismatch of no greater than 0.1 dB, and cross-polarization levels of no greater than about -45 dB. Since the radiation characteristics of phased arrays are inherently dependent on the scanning direction, it becomes even more challenging to meet these requirements. Furthermore, ensuring that each system in this large network meets the requirements becomes an additional challenge where accurate characterization and calibration will be critical. Clearly, the system and instrumentation used for characterization also need to meet or exceed the system level requirements to provide reliable weather-radar-based estimates. Given that radar and other communications systems require in-situ calibration, it is hypothesized that a UAV-based antenna measurement system is able to replace conventional outdoor ranges in virtue of its low cost and flexibility of operation. The proposed solution is a UAV-based in-situ antenna characterization system with the necessary RF instrumentation to perform accurate measurements of a typical weather radar, along with general guidelines and procedures to ensure optimal results. This solution attempts to provide a portable and cost-effective alternative to conventional outdoor antenna ranges, which can be deployed in multiple sites with few to no modifications. While previous works in the literature have had successful results in the use of UAVs for far-field (FF) antenna measurements in a variety of operating frequencies, no other work has currently shown the RF performance needed to meet the stringent requirements expected in an application such as polarimetric weather radars. It is shown in this work, that the characterization and calibration of real polarimetric weather radar systems is possible to a high degree of accuracy set forth by the most critical requirements, i.e., co-polarization mismatch no greater than 0.1 dB and cross-polarization levels below -45 dB. Advisors/Committee Members: Salazar Cerreno, Jorge (advisor), Fulton, Caleb (committee member), Palmer, Robert (committee member), Cheong, Boon Leng (committee member), Chilson, Phillip (committee member), Moghanloo, Rouzbeh (committee member).

Subjects/Keywords: Engineering, Electronics and Electrical.; Physics, Atmospheric Science.; Remote Sensing.; Engineering, Aerospace.

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APA (6^th Edition):

Umeyama Matsumoto, A. (2020). Unmanned Aerial Vehicle-based Far-Field Antenna Characterization System for Polarimetric Weather Radars. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/326678

Chicago Manual of Style (16^th Edition):

Umeyama Matsumoto, Arturo. “Unmanned Aerial Vehicle-based Far-Field Antenna Characterization System for Polarimetric Weather Radars.” 2020. Doctoral Dissertation, University of Oklahoma. Accessed March 05, 2021. http://hdl.handle.net/11244/326678.

MLA Handbook (7^th Edition):

Umeyama Matsumoto, Arturo. “Unmanned Aerial Vehicle-based Far-Field Antenna Characterization System for Polarimetric Weather Radars.” 2020. Web. 05 Mar 2021.

Vancouver:

Umeyama Matsumoto A. Unmanned Aerial Vehicle-based Far-Field Antenna Characterization System for Polarimetric Weather Radars. [Internet] [Doctoral dissertation]. University of Oklahoma; 2020. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/11244/326678.

Council of Science Editors:

Umeyama Matsumoto A. Unmanned Aerial Vehicle-based Far-Field Antenna Characterization System for Polarimetric Weather Radars. [Doctoral Dissertation]. University of Oklahoma; 2020. Available from: http://hdl.handle.net/11244/326678

10. Stepanian, Phillip. RADAR POLARIMETRY FOR BIOLOGICAL APPLICATIONS.

Degree: PhD, 2015, University of Oklahoma

URL: http://hdl.handle.net/11244/14632

► Radar aeroecology has steadily progressed since its inception in the 1950's, and additional advancements in radar technology, networks, modeling, and validation continue to drive the… (more)

▼ Radar aeroecology has steadily progressed since its inception in the 1950's, and additional advancements in radar technology, networks, modeling, and validation continue to drive the science further. As human impacts steadily increase within the airspace and across the landscape, conflicts with wildlife will motivate new solutions for mitigating these negative interactions. As one of the few sources of widespread surveillance of the aerosphere, radar will continue to play a valuable role in observing and quantifying animal life aloft. The United States' next-generation weather radar network (NEXRAD) provides national coverage of the airspace at ten-minute resolution. These data are quality controlled, archived, and freely available for download, resulting in an efficient source of animal observations. The NEXRAD weather surveillance radars have recently been upgraded to dual-polarizations, yielding three additional routine data products: differential reflectivity (ZDR), differential phase (phiDP), and co-polar cross-correlation coefficient (rhoHV). While much speculation has been generated over the application of these products to biological studies, little work has been done on the subject. The topic of this dissertation is the application of NEXRAD to biological studies, specifically focusing on the interpretation and use of polarimetric radar products. An overview of the polarimetric products is presented, and their biological interpretation is outlined. Laboratory radio scattering measurements are detailed, providing a technique for characterizing the radar characteristics of individuals. Typical manifestations of biological scatter are shown, including the roost emergences of bats and birds, as well as widespread nocturnal migration. From these polarimetric signatures in widespread migration, a method is developed that extracts profiles of migrant height orientations by exploiting morphological patterns in rhoHV. Finally, two validation methods are described using radar simulation and passive acoustic localization of nocturnal fight calls. Advisors/Committee Members: Chilson, Phillip (advisor), Palmer, Robert (committee member), Zhang, Guifu (committee member), Schuur, Terry (committee member), Kelly, Jeffrey (committee member).

Subjects/Keywords: Radar; Polarimetry; Birds; Bats

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APA (6^th Edition):

Stepanian, P. (2015). RADAR POLARIMETRY FOR BIOLOGICAL APPLICATIONS. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/14632

Chicago Manual of Style (16^th Edition):

Stepanian, Phillip. “RADAR POLARIMETRY FOR BIOLOGICAL APPLICATIONS.” 2015. Doctoral Dissertation, University of Oklahoma. Accessed March 05, 2021. http://hdl.handle.net/11244/14632.

MLA Handbook (7^th Edition):

Stepanian, Phillip. “RADAR POLARIMETRY FOR BIOLOGICAL APPLICATIONS.” 2015. Web. 05 Mar 2021.

Vancouver:

Stepanian P. RADAR POLARIMETRY FOR BIOLOGICAL APPLICATIONS. [Internet] [Doctoral dissertation]. University of Oklahoma; 2015. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/11244/14632.

Council of Science Editors:

Stepanian P. RADAR POLARIMETRY FOR BIOLOGICAL APPLICATIONS. [Doctoral Dissertation]. University of Oklahoma; 2015. Available from: http://hdl.handle.net/11244/14632

11. Mirković, Djordje. Computational Electromagnetics Applied to Scattering Observed by Polarimetric Weather Radar.

Degree: PhD, 2015, University of Oklahoma

URL: http://hdl.handle.net/11244/21720

► The primary topics of this dissertation are issues existing in the current ensemble scattering procedures. These procedures are failing to quantitatively reproduce polarimetric signatures from… (more)

▼ The primary topics of this dissertation are issues existing in the current ensemble scattering procedures. These procedures are failing to quantitatively reproduce polarimetric signatures from resolution volumes filled with ensembles of resonant size precipitation, biota, and anthropogenic scatterers. Sources of these failures are traced to the constraints on the topology that is admissible to the different modeling procedures. The dissertation evaluates in a systematic manner the current modeling procedures focusing on limitation sources and their effects on the overall process of polarimetric variable simulation. It re-evaluates limitations of the widely used T-Matrix approach and discusses sources of instability. Based on the identified limitations, a novel computational electromagnetics (CEM) approach to scatterer modeling and polarimetric variable calculation is introduced to mitigate the current limitations. Detailed overview of the process as well as guidance on applying the CEM to the polarimetric variable calculation is presented. This is the first systematic exploration of a specific CEM solver to modeling of polarimetric radar signatures from precipitation and biota. Finally, to demonstrate meteorological application the CEM approach is evaluated by comparison with some polarimetric radar observations of hail. Of main significance is modeling of large and giant hail having surface protuberances, or rough, irregular shape. Additionally, radar observations of biota and radar cross section (RCS) measurements are considered for aeroecology applications. As an example, the precise size and shape model of Brazilian Free-tailed bat (Tadarida brasiliensis) is created and compared to the RCS measurements, as well as to radar observations of bat emergence in Texas plains. Advisors/Committee Members: Zhang, Yan (advisor), Zrnic, Dusan (committee member), Doviak, Richard (committee member), Chilson, Phillip (committee member), Sigmarsson, Hjalti (committee member), Kelly, Jeffrey (committee member).

Subjects/Keywords: Computational Electromagnetics; Polarimetric Radar; Radar Cross Section

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

APA (6^th Edition):

Mirković, D. (2015). Computational Electromagnetics Applied to Scattering Observed by Polarimetric Weather Radar. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/21720

Chicago Manual of Style (16^th Edition):

Mirković, Djordje. “Computational Electromagnetics Applied to Scattering Observed by Polarimetric Weather Radar.” 2015. Doctoral Dissertation, University of Oklahoma. Accessed March 05, 2021. http://hdl.handle.net/11244/21720.

MLA Handbook (7^th Edition):

Mirković, Djordje. “Computational Electromagnetics Applied to Scattering Observed by Polarimetric Weather Radar.” 2015. Web. 05 Mar 2021.

Vancouver:

Mirković D. Computational Electromagnetics Applied to Scattering Observed by Polarimetric Weather Radar. [Internet] [Doctoral dissertation]. University of Oklahoma; 2015. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/11244/21720.

Council of Science Editors:

Mirković D. Computational Electromagnetics Applied to Scattering Observed by Polarimetric Weather Radar. [Doctoral Dissertation]. University of Oklahoma; 2015. Available from: http://hdl.handle.net/11244/21720

12. Flamig, Zachary Lolos. A HIGH RESOLUTION DISTRIBUTED HYDROLOGIC MODEL CLIMATOLOGY OVER THE CONTERMINOUS UNITED STATES FOCUSED ON FLASH FLOODING.

Degree: PhD, 2016, University of Oklahoma

URL: http://hdl.handle.net/11244/44865

► This study will describe the MRMS reanalysis precipitation dataset created for the time period from 2001 to 2011. This high resolution 1-km² 5-minute dataset is… (more)

Subjects/Keywords: Meteorology; Hydrology; Flooding

…University of Oklahoma (OU), NSSL, NASA, and commercial partner AccuWeather who owns the…

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

APA (6^th Edition):

Flamig, Z. L. (2016). A HIGH RESOLUTION DISTRIBUTED HYDROLOGIC MODEL CLIMATOLOGY OVER THE CONTERMINOUS UNITED STATES FOCUSED ON FLASH FLOODING. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/44865

Chicago Manual of Style (16^th Edition):

Flamig, Zachary Lolos. “A HIGH RESOLUTION DISTRIBUTED HYDROLOGIC MODEL CLIMATOLOGY OVER THE CONTERMINOUS UNITED STATES FOCUSED ON FLASH FLOODING.” 2016. Doctoral Dissertation, University of Oklahoma. Accessed March 05, 2021. http://hdl.handle.net/11244/44865.

MLA Handbook (7^th Edition):

Flamig, Zachary Lolos. “A HIGH RESOLUTION DISTRIBUTED HYDROLOGIC MODEL CLIMATOLOGY OVER THE CONTERMINOUS UNITED STATES FOCUSED ON FLASH FLOODING.” 2016. Web. 05 Mar 2021.

Vancouver:

Flamig ZL. A HIGH RESOLUTION DISTRIBUTED HYDROLOGIC MODEL CLIMATOLOGY OVER THE CONTERMINOUS UNITED STATES FOCUSED ON FLASH FLOODING. [Internet] [Doctoral dissertation]. University of Oklahoma; 2016. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/11244/44865.

Council of Science Editors:

Flamig ZL. A HIGH RESOLUTION DISTRIBUTED HYDROLOGIC MODEL CLIMATOLOGY OVER THE CONTERMINOUS UNITED STATES FOCUSED ON FLASH FLOODING. [Doctoral Dissertation]. University of Oklahoma; 2016. Available from: http://hdl.handle.net/11244/44865

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