CoAuthors

Seemanth M (Space application centre, india); Rashmi Sharma (Space application centre isro, India)

CFOSAT (the China France Oceanography Satellite) is a joint China and France mission, dedicated to the simultaneous observation ocean surface wind and surface gravity waves. This mission is unique in the sense that it would have a synergistic realization of both wind and waves at the same time. It aims to improve NWP and ocean state forecast for operational marine meteorology, advanced ocean state forecast, ocean process studies and modelling ocean dynamics, prediction of climate variability and will suffice to fundamental understanding the surface processes. The CFOSAT has two payloads Ku-Band radars. One is the wave scatterometer known as Surface Waves Investigation and Monitoring instrument (SWIM) and the other one is a wind scatterometer (SCAT). These two instruments are indeed very unique. SCAT is implementation of a new type of Rotating Fan-Beam Scatterometer. On the other hand, SWIM is a new space-borne instrument with technological innovations having Rotating antenna, on-board advanced digital processing. SWIM is conceived at a frequency of 13.5 Ghz in Ku band and operates in the VV polarization. It has 6 incidence angles at 0 2 4 6 8 and 10 degrees respectively on ground. The wind and integrated wave parameter like SWH is provided at nadir while at 6 8 and 10 degrees it would provide the essential wave spectra information. CFOSAT would therefore bring to us simultaneous and in the same zone, the directional spectra of ocean waves and the wind vector. The initial relative calibration of CFOSAT scat has been planned from India using the global land targets over Amazon, Greenland and Antarctica and Runn of Katch respectively. A decent cross calibration is also planned using the Indian scatterometers SCATSAT-1. The initial phase of SWIM spectra would be matched using the 2-dimentional wave model spectra from Wave watch-3 and SWAN.