FY-2静止卫星红外通道的高光谱交叉定标

介绍利用高光谱探测器IASI和AIRS对FY-2静止气象卫星VISSR红外通道进行绝对交叉定标的方法,并且基于FY-2E业务运行以来的历史数据对该方案进行可靠性检验和误差分析。结果表明,基于两个独立仪器得到的高光谱定标结果间具有很好的一致性;高光谱定标的亮温偏差基本上呈正态随机分布没有明显的系统偏差,平均亮温偏差小于0.07K,标准差约1.4K,其中亮温大于290K时,平均偏差小于0.2K,亮温大于220K时,平均偏差小于1K,低温端平均偏差约为3K;本文方法与目前FY-2EL1文件中提供的定标结果相比有明显改善,精度平均提高大于1K,低温端2—3K。长时间统计分析结果证明文中采用高光谱交叉定标方案稳定可靠,精度能够满足定量应用需求。

Inter-calibration of infrared channels of FY-2/VISSR using highspectral resolution sensors IASI and AIRS

Inter-calibration method for infrared channels of geostationary satellite FY-2/VISSR is introduced using the highspectral resolution sounder (HSRS) as a reference onboard a polar orbit satellite, i.e., METOP/IASI or AQUA/AIRS. Analyses on its reliability were performed based on FY-2E historical data since 2009. The results indicate that inter-calibration results based on the two independent sensors IASI and AIRS have a good consistency between them, and the mean blackbody temperature (TBB) bias of HSRS inter-calibration is about 0.07 K with standard deviation of 1.4 K, which proves that there is no systematic bias and the distribution of TBB bias is approximately normal. Thereinto, the mean TBB bias is approximately less than 0.2 K and 1 K when TBB is great than 290 K and 220 K, respectively, and is about 0.3 K at a lower temperature. Comparing with the operational calibration provided in the Level1 f iles, HSRS inter-calibration shows obviously improvements. Longtime statistic analyses demonstrate the HSRS inter-calibration method studied here is stable and reliable, and its accuracy can meet the requirement in quantitative applications.