On the radar signatures of oceanic fronts-analysis of multi-channel radar imagery and model predictions

The authors compare multi-channel radar images of the Gulf Stream front off the east coast of the US with results of numerical simulations based on available in-situ data. The radar images used for this study were acquired during the SIR-C/X-SAR campaign in 1994. According to model predictions, spatial variations in the surface current field and in the near-surface wind field at the Gulf Stream front can cause radar signatures of comparable shape and modulation depth. On the other hand, the individual dependencies of radar signatures of oceanic and atmospheric origin on radar frequency and polarization can be quite different. This enables the authors to identify radar signatures of oceanic and atmospheric origin in multi-channel data and to estimate the corresponding current and wind variations independently. By varying current and wind parameters at the Gulf Stream front within reasonable ranges, the authors arrive at a most likely scenario of oceanic and atmospheric conditions during the Shuttle overflight, for which good agreement between observed and simulated radar signatures is obtained at all radar channels