Radar-Derived Snowfall Microphysical Properties at Davis, Antarctica

Antarctic precipitation remains poorly characterized and understood, especially within the boundary layer. This is due in part to a still-limited amount of surface-based remote sensing observations. A suite of cloud and precipitation remote-sensing instruments including a W-band cloud radar and a K-band Micro Rain Radar (MRR) were used to characterize snowfall over Davis (69 degrees S, 78 degrees E). Surface snowfall events occurred when boundary layer wind speeds were weaker, temperatures were warmer, and relative humidity over ice higher than when virga were present. The presence of virga is associated with Fohn winds due to the location of Davis in the lee of an ice ridgeline. Dual wavelength ratio values from the summer indicate particle aggregation at temperatures of -14 degrees to -10 degrees C, consistent with observations made elsewhere, including in the Arctic. Riming frequency increases for temperatures above -10 degrees C and reaches 6.5% at -3 degrees C. No temperature dependence of rime mass fraction was found. Sublimation of snowfall mass aloft was 50% between the snow peak at 1.2 km and 205 m altitude, which occurs within CloudSat's "blind zone." Given the common prevailing wind direction and numerous ice ridgelines along much of the East Antarctic coastline, these Davis results can be used as a basis to further understand snowfall across the Antarctic region.