Multi-Frequency Radar/Passive Microwave retrievals of Cold Season Precipitation from OLYMPEX data

Due to the large natural variability of its microphysical properties, the characterization of solid precipitation over the variety of Earth surface conditions remain longstanding open issues for space-based radar and passive microwave (MW) observing systems, such the current Global Precipitation measurement (GPM) core satellite and the precipitation products produced by its constellation radiometers.

To assess the requirements for future cloud/precipitation observing systems, observations from the NASA DC-8 (radar profiles from the Advanced Precipitation Radar (APR-3) and two radiometers) were collected during November-December 2015 as part of the OLYMPEX-RADEX campaign in western Washington state, covering orographically evolving precipitation events with flight transects that covered transitions from ocean, coast, vegetation and snow-covered surfaces, regimes where there is less experience in modelling the joint atmospheric and land surface properties.

This study presents a novel technique combining the various radar and radiometer measurements in order to retrieve the snow properties such as mass and mean mass-weighed diameter. In particular, various state of the art scattering tables of snow aggregates available in the literature are used in order to highlight the primary growth process involved (i.e. aggregation or riming). First comparisons with in-situ observations from the coordinated flights of the Citation aircraft are presented.