To meet the demand of monitoring water pollution in China, Information Center of State Environmental Protection of China (ICSEP) and Institute of Remote Sensing Applications, Chinese Academy of Sciences (IRSA,CAS) have carried out a project to utilize the data extracted from Environment and Hazard Monitoring Constellation. This project is to build the first Remote-sensing and Environmental Monitoring System (REMS) in China. The most important component of REMS is the Hyperspectral-Environmental Database (HED). This paper is to describe the architecture and mechanism of HED. HED consists of five parts: Environmental backgrounds, Spectrums, Hyperspectral images, Basic geographic information and Environmental quality data. The interactions and relationships among the five parts are depicted. The workflow of HED assisting REMS is delineated. A preliminary research in Taihu Lake based on HED is also described in this paper.
The China-Brazil Earth Resources Satellite (CBERS) was developed by China in cooperation with Brazil. As one of the most important payload, CCD camera is expected to play an important role in the application of CBERS. Vicarious calibrations have been conducted every one year and cross-calibration is one of the methods to the calibration. Our effort is to probe the methodology of radiometric cross-calibration the CCD with MODIS and detect the degradation of the CCD camera since it was launched. The radiometric and reflectance coefficients and offsets for four CCD spectral bands were obtained based on the cross-calibration with four calibration targets. Results were validated by the synchro surface targets spectral measurement at Dunhuang site. The TOA radiances from calculation and simulation were consistent within 1%. Comparing our results with the coefficients based on vicarious calibration show that the average variation of the two independent methods was with 6%. Based on many times of radiometric-cross calibration of the CCD with the MODIS, the time series of radiometric coefficients for the CCD were obtained. Results illuminated that the response of the CCD have degraded, which could reach up to 3%- 7% per month
TERRA MODIS band 31 was selected as the criterion for doing the radiometric cross-calibration of CBERS-02 IRMSS band 9 in this paper. From August to December, 2004, seven times day and night synchronous images of two sensors passing through the Lake Qinghai and Lake Taihu were selected to get the cross-calibration data. Using TERRA MODIS band 31 data to conduct out the at pupil radiance of CBERS-02 IRMSS band 9 based on the two sensors' spectrum matching, and then pick-up the DN values from the IRMSS data in the same area. A new model to calculate the radiometric calibration coefficients was carried out in this paper: multi-points linear regression method with 7 times day and night synchronous images at different dates and locations. This new method can obviously control the radiometric calibration uncertainties aroused by the single point method to do the in-flight calibration like CBERS-02 IRMSS, this kind of sensors can't collect the radiometric signals from the deep space. In this research, the radiometric calibration coefficients obtained through the linear regression method were 8.0567 (gain, unit: DN/ (W/m2/sr1/μm1))
and 47.892 (offset, unit: DN). Preliminary estimate of calibration coefficients using Shanghai area was carried out and the results showed that the calibration coefficients obtained from the linear regression method was with a similar precision to TERRA MODIS band 31's. This suit of calibration coefficients can satisfy the quantitative applications of CBERS-02 IRMSS thermal data.