Graduate Exam Abstract
Tunde Adubi
M.S. Final
May 6, 2024, 2:00 pm - 3:00 pm
LSC 226-28
Fusion of Observations from C-band Polarimetric Radar and S-band Profiler Radar During a Convective Storm.
Abstract: This study discusses a procedure to measure and correct attenuation of the radar signals caused by the presence of partially melted ice hydrometeors (graupels and hails) in convective storms by utilizing simultaneous observations from a C-Band dual-polarization scanning radar and a vertically pointing S-Band profiler radar. The C-Band radar, used in this study, is known as the Atmospheric Radar for Meteorological and Operational Research (ARMOR) radar, situated in Huntsville, Alabama. Also, the S-Band profiler radar is maintained by the NOAA Physical Sciences Laboratory (PSL) and is about 50 kilometers west of the ARMOR radar site. A convective storm event characterized by squall lines is investigated. Within the squall line region, the presence of partially melted ice particles led to significant attenuation of the radar signal at C-Band, resulting in reduced reflectivity (Z). To address this issue, a conventional attenuation correction approach based on differential propagation phase measurements for rain medium was applied and compared with measurements from the S-Band profiler. The analysis revealed that correcting for rain attenuation alone was insufficient to address the heightened attenuation caused by melting ice hydrometeors. Consequently, a new attenuation correction methodology was developed, accounting for melting ice hydrometeors. Initially, profiles of specific differential propagation phase (Kdp) were studied to identify the exact location (range gates) containing melting ice particles. An attenuation correction coefficient for melting ice hydrometeors was estimated, and a piecewise attenuation correction procedure was implemented to address regions of rain and melting ice hydrometeors separately. Validation of the new attenuation correction technique involved simultaneous comparison of vertical reflectivity profiles obtained from the C-Band and S-Band profiler radar. Both instruments were matched spatially and temporally due to different viewing geometry. The results demonstrate that the new approach significantly enhanced the correlation between profiler measurements and attenuation-corrected radar reflectivity from the C-Band radar. Overall, this thesis determines experimentally, the attenuation coefficient in melting ice that is not available much in the literature today.
Adviser: V. Chandrasekar
Co-Adviser: N/A
Non-ECE Member: Ketul Popat
Member 3: Margaret Cheney
Addional Members: N/A
Publications:
N/A
Program of Study:
ECE512
ECE514
ECE556
ECE580
ECE421
ECE578
ECE658
ECE699
