Airborne Observation of ocean surface roughness variations using a combination of microwave radiometer and reflectometer systems - The second Virginia offshore (Virgo II) experiment

Airborne and satellite retrieval of Sea Surface Salinity (SSS) using L-band microwave radiometers requires accurate corrections for the influence of wind-induced Sea Surface Roughness (SSR) on the retrievals. We describe an airborne experiment, Virgo II, that combined an L-band microwave radiometer for retrieving SSS, with L- and S-band reflectometer systems for retrieving SSR descriptors including Mean Square Slope (MSS) and Wind Speed (WS) under a range of surface wind and wave conditions. The research objective is to use the SSR descriptors derived from the reflectometers to correct the brightness temperatures observed by the L-band radiometer, and produce more accurate SSS retrievals. Here we describe our experimental investigations to assess the feasibility of this approach. Preliminary comparisons of WS data retrieved from the reflectometers with coincident WS data from in situ platforms and an atmospheric circulation model indicate that after correcting for apparent biases, the reflectometry-derived SSR descriptors could, indeed, provide reliable corrections for the L-band radiometer salinity retrieval.