# Radiometric Calibration of the Near-Infrared Bands of GF-5-02/DPC for Water Vapor Retrieval
); [EMAIL_ADDRESS] (Y.L. );  
[PERSON]  
1 Shanghai Institute of Satellite Engineering, Shanghai 201109, China; [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (L.Z. ); [EMAIL_ADDRESS] (M.Z. ); [EMAIL_ADDRESS] (Y.L. );  
[PERSON]  
1 Shanghai Institute of Satellite Engineering, Shanghai 201109, China; [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (L.Z. ); [EMAIL_ADDRESS] (M.Z. ); [EMAIL_ADDRESS] (Y.L. );  
[PERSON]  
1 Shanghai Institute of Satellite Engineering, Shanghai 201109, China; [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (L.Z. ); [EMAIL_ADDRESS] (M.Z. ); [EMAIL_ADDRESS] (Y.N);  
[PERSON]  
1 Shanghai Institute of Satellite Engineering, Shanghai 201109, China; [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (L.Z. ); [EMAIL_ADDRESS] (M.Z. ); [EMAIL_ADDRESS] (Y.L. );  
[PERSON]  
1 Shanghai Institute of Satellite Engineering, Shanghai 201109, China; [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (L.Z. ); [EMAIL_ADDRESS] (M.Z. ); [EMAIL_ADDRESS] (Y.L. );  
[PERSON]  
1 Shanghai Institute of Satellite Engineering, Shanghai 201109, China; [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (L.Z. ); [EMAIL_ADDRESS] (M.Z. ); [EMAIL_ADDRESS] (Y.L. );  
[PERSON]  
1 Shanghai Institute of Satellite Engineering, Shanghai 201109, China; [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (L.Z. ); [EMAIL_ADDRESS] (M.Z. ); [EMAIL_ADDRESS] (Y.N);  
[PERSON]  
1 Shanghai Institute of Satellite Engineering, Shanghai 201109, China; [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (L.Z. ); [EMAIL_ADDRESS] (M.Z. ); [EMAIL_ADDRESS] (Y.L. );  
[PERSON]  
1 Shanghai Institute of Satellite Engineering, Shanghai 201109, China; [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (L.Z. ); [EMAIL_ADDRESS] (M.Z. ); [EMAIL_ADDRESS] (Y.N);  
[PERSON]  
1 Shanghai Institute of Satellite Engineering, Shanghai 201109, China; [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (L.Z. ); [EMAIL_ADDRESS] (M.Z. ); [EMAIL_ADDRESS] (Y.N);  
[PERSON]  
1 Shanghai Institute of Satellite Engineering, Shanghai 201109, China; xieyo@radi. advanced hyperspectral imager (AHSI), and other sensors onboard the GF-5-02 satellite platform. For these reasons, the DPC is equipped with two near-infrared (NIR) bands at 865 and 910 nm (referred to as NIR08 and NIR09 bands), so as to obtain PWV data synchronized with the GF-5-02 satellite. Moreover, due to the significant temporal and spatial differences in the water vapor distribution and the varying transit times of various satellites [4], the DPC is also important to enhance global PWV monitoring. Recently, a PWV retrieval algorithm has been specifically established for the DPC onboard the GF-5-02 satellite [5]. This algorithm employs the two bands at 865 and 910 nm of the DPC. The core principles of the algorithm are as follows. For any pixel in need of retrieving PWV, the water vapor absorption transmittance (WVAT) of the NIR09 band would be calculated first by dividing the top of the atmosphere (TOA) reflectance of the NIR09 band by that of the NIR08 band. Subsequently, the WVATs of the NIR09 band for various PWV contents are simulated by using a radiative transfer model (RTM). Finally, the one with the smallest difference between the simulated WVAT and the calculated WVAT is selected, and the PWV value corresponding to the simulated WVAT is the PWV retrieval result. To enhance the PWV retrieval efficiency, a look-up table is reconstructed to avoid using the RTM at any one pixel. Nevertheless, due to the systematic errors in the observations of the NIR bands used for monitoring PWV, the DPC PWV data developed through the algorithm exhibit notable errors [5]. To reduce the error of DPC PWV data, it is necessary to perform radiometric calibration at the two bands at 865 and 910 nm. Due to the lack of a calibration system for DPC, researchers have developed a large number of in-orbit vicarious calibration methods for DPC. [PERSON] et al. conducted radiometric calibration of four bands (443, 490, 565, and 670 nm) of the DPC in the South Atlantic using the Rayleigh calibration method.