An Evaluation of Cold Season Precipitation Microphysical Properties from a Radar Perspective

Snowfall plays a key role in the global hydrologic cycle and can have substantial impacts on the environmental, economic, and social sectors ranging from water resource management to climate change. As a result of these ramifications, the ability to detect and measure falling snow at the surface is of great importance. Currently, accurate global surface snowfall measurements are not possible due to the limitations of ground-based instrumentation coupled with the uncertainty in spaceborne retrievals. The recently launched NASA Global Precipitation Measurement (GPM) mission core observatory opens up the potential for near-global real-time, accurate satellite retrievals of snowfall, however additional research is necessary to fully understand snowfall properties and allow for the ability to produce the algorithms for such retrievals.

This study seeks to investigate the relationship between observed wintertime precipitation microphysical parameters and their associated radar retrieval signatures using ground-based data collected during the NASA GPM Cold-season Precipitation Experiment (GCPEx) that took place in southern Ontario, Canada during January and February of 2012. Microphysical properties including particle size distributions, mass-diameter relationships, effective bulk density, and fall speed are calculated using the two-dimensional video disdrometer (2DVD), Particle Size Velocity (PARSIVEL-2) disdrometer, and Snow Video Imager (SVI) for varying precipitation conditions including light, moderate, and heavy snow as well as multiple storm types such as synoptic, lake enhanced, and lake effect events. The varying properties are then compared to coincident radar dual-polarization and multi-wavelength signatures of differing wavelengths including C-, Ku-, Ka-, X-, and W-Band in order to determine the effects the microphysical properties have on the radar signatures.