X-band polarimetric radar observations of an Arctic shallow boundary layer cloud

 
Poster PDF

Authors

Mariko Oue — Stony Brook University
Johannes Verlinde — The Pennsylvania State University
Eugene E. Clothiaux — Pennsylvania State University
Kultegin Aydin — Pennsylvania State University

Category

Ice Nucleation and Cloud Phase

Description

The microphysics and mesoscale structure of an Arctic shallow boundary layer cloud system observed during the May 2013 NSA-Radar IOP were examined using X-SAPR radar measurements. The shallow multilayer boundary layer cloud system was characterized by widely-distributed broken stratocumulus with cloud tops below 1 km with another layer a few 100 m above the stratocumulus. Sounding measurements indicated pristine dendrite growth regimes (temperature < -10 °C) at all altitudes. High spectral resolution lidar measurements suggested a persistent thicker (~250 m) liquid-cloud layer at heights between 0.3 km and 0.6 km with few breaks and a thinner (< 100 m) liquid-cloud layer aloft. The X-SAPR Plan Position Indicator (PPI) measurements recorded differential reflectivity values lower than 2 dB with higher copolar correlation coefficients during periods of unbroken thicker liquid-cloud layers, but much higher differential reflectivity values of 6 dB with lower copolar correlation coefficients during periods of broken thicker liquid-cloud layer. These polarimetric radar signatures suggest growth of spatial ice particles by riming and/or aggregation in and below the thicker liquid-cloud layer and isolated pristine dendrite growth in and below the thinner liquid-cloud layers. We will discuss these detailed microphysical observations from the X-SAPR in conjunction with analyses of millimeter-wavelength radar (i.e. SACR) and lidar measurements.

Lead PI

Johannes Verlinde — The Pennsylvania State University