Swell Effects on Near-Coastal Smap L-Band High-Resolution NRCS Data

In this paper, physical models for ocean surface swell effects on L-band backscatter at 40° incidence angle are used to interpret measurements from NASA's Soil Moisture Active/Passive (SMAP) radar. The backscatter normalized radar cross section (NRCS) of the ocean surface is predicted using the two-scale (or composite surface) model (TSM). The wind-driven ocean surface in the model is characterized using the Durden-Vesecky directional spectrum, while swell effects are represented through their contribution to the long wave slope variance. The excess slope variance attributed to swell is then obtained from the Wave Watch III wave model. Preliminary comparisons in HH polarization show an improved agreement between modeled and observed NRCS data when swell effects are included.