Date of Award
Master of Science (MS)
Atmospheric and Earth Science
Lawrence D. Carey
Radiometers, Microwaves, Snow--Remote sensing, Cloud physics
When precipitation becomes organized into bands, it can result in great differences in precipitation accumulation across a geographic area with disruptions to daily life and economic activity. While investigations have been conducted to discern microphysical details within banded precipitation environments, such details remain very uncertain across and within storms. It is the goal of the Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) to gather data using satellite-simulating and in situ aircraft to study banded storms. This study focuses on the Conical-Scanning Millimeter-wave Imaging Radiometer (CoSMIR), The Advanced Microwave Precipitation Radiometer (AMPR), and The High Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) due to their sensitivity to precipitation microphysics. The individual and combined strengths and weaknesses of these instruments are assessed in a variety of precipitation environments over land and water. In general, AMPR is well suited for detecting light precipitation and differentiating liquid precipitation intensities over water. The 37-GHz channel could warm near 20 K in response to precipitation columns below Ku-indicated 25 dBZ, while the 10-GHz channel could resolve rain intense enough to saturate all other liquid-sensitive channels. CoSMIR demonstrates enhanced sensitivity to cloud ice quantity and altitude, with increasingly high cloud tops manifesting as increasingly low CoSMIR brightness temperatures. Over land, radiometer efficacy is diminished, leading to increased reliance on the HIWRAP radar to assess storm structure. Use of a dual frequency ratio (DFR) product derived from HIWRAP's Ku and Ka bands provided greater insight into storm microphysics than reflectivity alone. On average, mixed-phase precipitation had the highest DFR (usually above 17), while high-altitude ice clouds were generally below 1.5 DFR. Rain columns below the bright band increased DFR as distance from the bright band increased, and snow bands were easier to distinguish in DFR, appearing around 8 DFR higher than the surrounding cloud mass.
Richter, Amanda, "An airborne multi-band microwave analysis of precipitation within two winter cyclones" (2023). Theses. 448.