Preliminary study on the orbit cross-calibration of CMODIS by SeaWiFS

China launched its third spaceship SZ 3 in March, 2002 on which the main remote sensor is the Chinese moderate imaging spectra radiometer (CMODIS). In this paper the properties of CMODIS are firstly introduced briefly. Then, the theory and algorithm of cross calibration for CMODIS ocean color channels by the sea viewing wide field of view sensor (SeaWiFS) data are discussed in detail. The total radiance (TOA) of four quasi synchronized crossing ocean areas simulated by SeaWiFS and measured by CMODIS are compared and the calibration coefficients are derived from the relationship between them. Finally, the in situ water leaving radiance data are used to validate the calibration results. The results show that the cross calibration method could provide reasonable precision for ocean color measurement.