COMPARISON OF OMNIDIRECTIONAL OCEAN WAVE SPECTRA FROM CFOSAT SWIM OBSERVATIONS AND FROM BOUY OBSERVATIONS

The Surface Waves Investigation and Monitoring (SWIM) omnidirectional wave spectra and its shape parameters are compared by matching the SWIM wave spectrum data with the buoy wave spectra of the National Data Buoy Center (NDBC). The results show that the omnidirectional wave spectrum of SWIM has significant overestimation at low frequencies and significant underestimation at high frequencies. And there are spurious peaks at low frequencies. The overestimation and underestimation of the SWIM 6 degrees beam wave spectrum are the most obvious. We believe that the presence of spurious peaks is due to the amplification of the noise floor in the SWIM omnidirectional spectrum at low frequencies. This phenomenon is greatly relieved with the increase of Significant Wave Height (SWH). The difference between the SWIM spectrum shape parameters frequency spread ( sigma(f) ) and the "peakedness" of the omnidirectional spectrum ( Qp ) and the buoy is large. The difference between them decreases significantly with increasing SWH.