A comparison of OCI and SeaWiFS satellite imagery in the waters adjacent to Taiwan

With the successful launch of the first scientific satellite of the Republi c of China (ROCSAT-1) on 27 January 1999, Taiwan enters the era as a satell ite data providing country. There are three scientific payloads on the sate llite. One of them is the Ocean Color Imager (OCI). OCI is a push-broom ref lective imager for monitoring ocean colors. OCI has taken images since Marc h 1999. Because there is no on-board calibrator on OCI, a comparison with S ea-viewing Wide Field-of-view Sensor (SeaWiFS) data was performed in order to validate OCI data. Simultaneously in-situ observations of optical proper ties and chlorophyll a concentration were also collected in waters adjacent to Taiwan for vicarious calibration. We applied SeaWiFS atmospheric correc tion and bio-optical algorithms on OCI data to derive normalized water-leav ing radiance and chlorophyll a concentration. Results show that the chlorop hyll a concentration derived from OCI is generally larger than that derived from SeaWiFS. The correlation coefficient is about 0.60 with a root-mean-s quared (RMS) of difference of chlorophyll a concentration of 0.10 mg/m(3).