Studies of a C-band model function for friction velocity using coincident, simultaneous Ku-band scatterometer measurements

C-band scatterometer measurements during SWADE are being combined with coincident sea surface friction velocity estimates to create a new model function. The goal is to develop the capability of making friction velocity estimates (and surface stress) from radar cross section data acquired by the ERS-1 satellite scatterometer. Both Ku-band and C-band scatterometers were operated simultaneously for extensive intervals for each of 10 days during SWADE. The model function developed previously from FASINEX converts the Ku-band RCS measurements into friction velocity. The results show the C-band RCS dependence at 20, 30, 40 and 50 degrees to be less sensitive to friction velocity than the corresponding cases for Ku-band. Spatial variations of u* across the Gulf Stream are also studied in conjunction with supporting measurements of air-sea temperature and wind fields