海洋水色水温扫描仪精确大气漫射透射比计算

Exact Computation of Atmospheric Diffuse Transmittance for Chinese Ocean Color and Temperature Scanner

海洋水色水温扫描仪(COCTS)是中国海洋水色系列卫星上的主遥感器,主要用于探测我国及全球部分海域的海洋水色和水温环境信息。大气漫射透射比计算是COCTS大气校正的必需过程,直接影响COCTS大气校正和水色信息反演的精度。提出了基于加倍法解大气-海洋耦合矢量辐射传输方程的大气漫射透射比精确计算方法,通过与SeaWiFS精确大气漫射透射比查找表计算结果的比较,结果表明计算相对误差小于1.5%,而当观测天顶角小于60°时,计算相对误差小于0.5%,可以用来生成COCTS的精确大气漫射透射比查找表。在此基础上,生成了专门针对COCTS的精确大气漫射透射比查找表。

Chinese ocean color and temperature scanner （COCTS） is the main sensor on the Chinese ocean color series satellites, which is used for real-time monitoring of the ocean color and sea-surface temperature of the sea areas around China and part of the global ocean. The calculation of atmospheric diffuse transmittance is required in the ocean color atmosphere correction which affects the accuracy of the atmosphere correction and ocean color information retrieving. An exact computation method of atmospheric diffuse transmittance is developed based on the vector radiative transfer equation （VRTE） which is solved by adding-doubling method. Comparison with the diffuse transmittance derived from SeaWiFS exact diffuse transmittance look-up table, proves that the relative error of this adding-doubling method is less than 1.5 %, and when the observing zenith angle is less than 60°, the relative error is even less than 0.5 %. Therefore, the adding-doubling method can be used to generate the exact atmospheric diffuse transmittance look-up table for the Chinese ocean color and temperature scanner （COCTS）. Finally, using the developed vector radiative transfer code with adding-doubling method, we generate exact atmospheric diffuse transmittance look-up tables for COCTS.