Start
April 25, 2024 - 1:30 pm
End
April 25, 2024 - 2:00 pm
Categories
Convective Meteorology (Mesoscale Dynamics)ARRC Seminar
Amanda G. Richter
An Airborne Multifrequency Microwave Analysis of Precipitation within Two Winter Cyclones
Thursday, April 25th
1:30 pm / NWC 1350
If unable to attend, please join via zoom meeting:
https://oklahoma.zoom.us/j/93078394162?pwd=Y2ZlRDBnNVRJUlBrUERqL2pWYUlHdz09
Meeting ID: 93078394162
Passcode: 06207489
Abstract: NASA’s Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) field campaign gathered data using “satellite-simulating” (albeit with higher-resolution data than satellites currently provide) and in situ aircraft to study snowstorms, with an emphasis on banding. This study used three IMPACTS microwave instruments—two passive and one active—chosen for their sensitivity to precipitation microphysics. The 10–37GHz passive frequencies were well suited for detecting light precipitation and differentiating rain intensities over water. The 85–183GHz frequencies were more sensitive to cloud ice, with higher cloud tops manifesting as lower brightness temperatures, but this did not necessarily correspond well to near-surface precipitation. Over land, retrieving precipitation information from radiometer data is more difficult, requiring increased reliance on radar to assess storm structure. A dual-frequency ratio (DFR) derived from the radar’s Ku- and Ka-band frequencies provided greater insight into storm microphysics than reflectivity alone. Areas likely to contain mixed-phase precipitation (often the melting layer/bright band) generally had the highest DFR, and high-altitude regions likely to contain ice usually had the lowest DFR. The DFR of rain columns increased toward the ground, and snowbands appeared as high-DFR anomalies.