In-flight Absolute Calibration of the CBERS-02 CCD Sensor at the Dunhuang Test Site

Since(CBERS- 02) was successfully launched on October 21,2003,the data of(CBERS- 02) has been widely applied to the fields for agriculture,forestry,geology,water conservancy ect.It is very necessary to update the coefficient of absolute radiometric calibration in order to deeply carry on the research of quantitative approaches.Therefore,China Centre for Resources Satellite Data Application team has conducted a field measurement campaign for the characteristic of ground reflectance and of the atmosphere.The results show that the test site of Dunhuang is very homogeneous and the variation of ground material reflectance is about 5%.The results of atmospheric measurements have shown that the aerosol optical depth(0.14) is very low.The coefficients of CBERS- 02 CCD sensor for four bands have been obtained through the "6S" atmospherical transfer code.Simultaneously,the cross-calibration of Landsat-5 TM and CBERS- 02 CCD based on the image of August 25,2004 was made.It shows that the consistency between the results from Dunhuang site calibration and cross-calibration varies less than 6% except band 3.The field measurement verified the radiometric performance and reliability for the absolute calibration of CBERS- 02 CCD sensor.