Browsing OU - Dissertations by Author "Zhang, Guifu"
Now showing items 1-20 of 24
-
Analysis and Design of Reflectarray Antennas for Radar System Applications
Pan, Yu (2014)In recent years reflectarray has received more and more attention and it has been considered as a suitable candidate to replace the traditional reflectors due to its high-gain, low profile and low cost features. Reflectarray ... -
Analysis of the Dynamics and Microphysics of a Wet Downburst Case Using Dual-Polarization Radar Data
Mahale, Vivek (2019-05-10)A significant, wet downburst affected Norman, Oklahoma, on 14 June 2011. Surface winds in excess of 35 m/s (>80 mph) and hailstones in excess of 4 cm diameter occurred during the downburst. The polarimetric S-band (~11.09-cm ... -
ASSESSMENT OF ONE-MOMENT AND TWO-MOMENT BULK MICROPHYSICS AND SPECTRAL BIN MICROPHYSICS SCHEMES USING IDEALIZED SUPERCELL SIMULATIONS AND REAL DATA CONVECTIVE-SCALE PREDICTIONS
Johnson, Marcus (2019-05)Optimal hydrometeor parameterization and their associated processes in microphysics schemes (both spectral bin and bulk) continue to evolve as these schemes attempt to match observed hydrometeor complexity. This dissertation ... -
A BALLOON-BORNE PARTICLE SIZE, IMAGING, AND VELOCITY PROBE FOR IN SITU MICROPHYSICAL MEASUREMENTS
Waugh, Sean (2016-12-16)A balloon-borne instrument known as the PArticle Size, Image, and Velocity (PASIV) probe has been developed at the National Severe Storms Laboratory to provide in situ microphysical measurements in storms. These observations ... -
CLUTTER DETECTION AND MITIGATION FOR DUAL-POLARIZATION WEATHER RADAR
Golbon-Haghighi, Mohammad-Hossein (2019-12-13)Ground clutter in weather radar observations causes degradation of data quality and can lead to misinterpretation of radar echoes. It is important to detect clutter and mitigate its effects to obtain accurate weather ... -
CYLINDRICAL POLARIMETRIC PHASED ARRAY RADAR DEMONSTRATOR: PERFORMANCE ASSESSMENT AND WEATHER MEASUREMENTS
Li, Zhe (2020-07-30)A desirable candidate for future weather observation is a polarimetric phased array radar (PPAR), which is capable of both using polarimetry for multi-parameter measurements and the fast-scan proficiency of the PAR. However, ... -
DESIGN AND IMPLEMENTATION OF A PHASED ARRAY ANTENNA FOR MULTI-MISSION APPLICATIONS
Mirmozafari, Mirhamed (2018)Multifunction Phased Array Radar (MPAR) was defined to investigate the feasibility of integrating weather observation and air surveillance radars into a single network. Weather radars require dual polarization capability ... -
Diagnosis of Severe Wind Processes in Two Nocturnal MCSs Observed during PECAN
Miller, Rachel (2023-08-04)Severe wind processes in nocturnal mesoscale convective systems (MCSs) are not well understood since historically it has been assumed that these systems are elevated due to a stable surface layer. However, recent studies ... -
FOUR-DIMENSIONAL ENSEMBLE KALMAN FILTER ASSIMILATION OF HIGH TEMPORAL RESOLUTION PHASED ARRAY RADAR DATA WITH REAL CONVECTIVE STORM CASES
Supinie, Timothy (2020-05)With the US National Weather Service (NWS) Weather Surveillance Radar-1988 Doppler (WSR-88D) radar network aging, a candidate for replacing it is phased array radar (PAR). The defining feature of PAR is an electronically ... -
HIGH-PERFORMANCE ANTENNA ARRAYS FOR MULTIFUNCTION PHASED ARRAY RADAR (MPAR) APPLICATION
Saeidi Manesh, Hadi (2019-05-10)There are interest and practical value in utilizing polarization diversity for a radar to obtain more target information or for a communication system to carry more signal information without occupying more frequency band. ... -
Limitations and Potential of Complex Cloud Analysis and Its Improvement for Radar Reflectivity Data Assimilation Using OSSEs.
Tong, Chong-Chi (2015-12-18)The radar data assimilation is very important for improving short-range precipitation forecasts. Within the three dimensional variational (3DVAR) framework which is still the prevailing method used for operational regional ... -
OBSERVATIONAL STUDY OF RAIN MICROPHYSICS AND RAIN RETRIEVAL USING POLARIMETRIC RADAR DATA
Cao, Qing (2009)Accurate quantitative precipitation estimation (QPE) and quantitative precipitation forecasts (QPF) require accurate microphysical parameterization/modeling of the precipitation. This study presents the modeling of rain ... -
Observations and Simulations of Polarimetric, X-Band Radar Signatures in Supercells
Snyder, Jeffrey (2013)Polarimetric weather radars, with the additional information collected, allow one to infer scatterer and precipitation properties considerably more easily than single-polarization radars. Given the relationship between the ... -
Observations of Evolving Lightning, Microphysics, and Kinematics for a Supercell, a Multicell, and a Mesoscale Convective System
DiGangi, Elizabeth (2019)The Deep Convective Clouds and Chemistry (DC3) field experiment collected data on a variety of storms to investigate the relationships between lightning and other storm processes. This study focuses on the relationships ... -
A Polarimetric and Microphysical Investigation of Winter Storms
Griffin, Erica (2018-12)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 ... -
Polarimetric and Rapid-Scan Radar Observations of Tornadoes
Griffin, Casey (2019)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 ... -
Polarimetric Measurements of Ice Pellets and Aggregated Snow
Bukovcic, Petar (2017-12-15)The recent upgrade of the National Weather Service WSR-88D radar network to polarimetric capabilities provides the abundance of information about the precipitation microphysics. Even with the plethora of polarimetric ... -
THE PREDICTION AND ASSIMILATION OF POLARIMETRIC RADAR DATA USING ENSEMBLE-BASED METHODS
Putnam, Bryan (2016-05-13)Accurately representing the microphysical state of precipitation using bulk microphysics schemes, including the hydrometeor particle size distributions (PSDs), is vital to improving convective-scale forecasts. In this ... -
Pulse Compression Waveforms and Applications for Weather Radar
Kurdzo, James (2015-12-18)The progression of phased array weather observations, research, and planning over the past decade has led to significant advances in development efforts for future weather radar technologies. However, numerous challenges ... -
RADAR POLARIMETRY FOR BIOLOGICAL APPLICATIONS
Stepanian, Phillip (2015-05-08)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 ...