Fully Polarimetric Radar Signals in Winter Storms in the IMPACTS Field Campaign

Understanding ice precipitation processes is critical to understanding the broader picture of winter weather. The Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) field campaign provides a unique opportunity to combine research-grade radar and in-situ observations. From this campaign, we have a wealth of information to contribute to our understanding of the processes leading to, and detailed microphysical properties of, winter precipitation events.

During IMPACTS, the Ka-band Scanning Polarimetric Radar (KASPR) located at Stony Brook University also collected data. KASPR is a great asset for observing winter precipitation, given its fine spatial resolution and fully polarimetric capabilities, allowing for observations of variables including linear depolarization ratio (LDR), cross-polar correlation coefficient (RhoXH), and the cross-polar phase shift (PhiXH). The signals in these variables relate to depolarization of the radar signal and ice particle properties. Signals in LDR have been associated with columnar ice crystals, and signals in RhoXH and PhiXH are consistent with columnar ice crystals with orientations canted with respect to the polarization plane.

This project will examine the fully polarimetric radar signals from KASPR in harmony with in situ measurements from the IMPACTS P-3 aircraft probes to determine the processes associated with those radar signals in multiple IMPACTS cases. Because we are focusing on lesser-studied fully polarimetric variables including the cross-polar correlation coefficients and phases, this work will be supplemented by scattering calculations for ice particles. These scattering calculations indicate that signals in the cross-polar radar variables are related to ice crystal habits and orientations.