Degradation Analysis for FY3B/VIRR Reflective Solar Bands Based on the Dunhuang Radiometric Calibration Site
Lü Jia-yan1, CHEN Lin2, 3, HE Ming-yuan1*, HU Xiu-qing2, 3
1. College of Meteorology and Oceanography, PLA University of Science and Technology，Nanjing 211101, China
2. National Satellite Meteorological Center, China Meteorological Administration, Beijing 100081, China
3. Key Laboratory of Radiometric Calibration and Validation for Environmental Satellite, China Meteorological Administration, Beijing 100081，China
Abstract：The Visible and Infrared Radiometer (VIRR) boarded on FY3B which is the new generation polar orbit meteorological satellite of China needs constant radiometric calibration after launch for improving the quality of data and better meeting the needs of users. In order to investigate the radiometric response degradation of FY3B/VIRR, the radiometric calibration coefficients of its reflective solar bands are calculated by the reflectance-based method, using the in-situ experiment data of Dunhuang radiometric calibration site from 2011 to 2015. The corresponding relative standard deviation of each band’s radiometric calibration coefficient is less than 1.5%, except band 10 which is influenced by water vapor absorption. By comparing with the Aqua/MODIS observation data, the average deviation of our results is less than 2.5%. Then, the annual degradation rates of VIRR are achieved based on its five-year calibration coefficients, compared with the pre-launch calibration coefficient. This paper suggests that: (1) The degradation rate depends on the wavelength of the band, the degradation rate increases with the decrease of wavelength; (2) Compared with the pre-launch calibration coefficient, the VIRR sensor shows dramatic radiometric response change after one-year orbiting operation; (3) In general, the degradation rate decreases with the extension of operating time, especially in the second and the third year; (4) After three-year orbiting operation, the degradation rate of the band with wavelength less than 0.8μm appear to increase; (5) After two-year orbiting operation, the radiometric response of the band with wavelength greater than 0.8μm increases in some period; (6) Comparing to the degradation changes of FY3A/MERSI proposed by Sun, both of the two sensors demonstrate a negative correlation between the degradation rate and the wavelength, but the radiometric responses of MERSI’s band 3 and 13 at 0.65 μm appear to increase, on the contrary, the degradation of VIRR’s band 1 at the same wavelength tends to increase; (7) The annual degradation rate of short wavelength band 7, 8 and 9 is greater than 5% in the long run.
Key words：FengYun-3B(FY3B); Visible and infrared radiometer (VIRR); The reflectance-based method; Degradation analysis
吕佳彦，陈 林，何明元，胡秀清. 基于敦煌辐射校正场的FY3B/VIRR反射太阳波段衰减分析[J]. 光谱学与光谱分析, 2017, 37(08): 2397-2401.
Lü Jia-yan, CHEN Lin, HE Ming-yuan, HU Xiu-qing. Degradation Analysis for FY3B/VIRR Reflective Solar Bands Based on the Dunhuang Radiometric Calibration Site. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2017, 37(08): 2397-2401.
