Assessing the sun glint effect on the data bias of CrIS shortwave surface channels near 3.7 mu m

作者：Yin Mengtao^*

来源：International Journal of Remote Sensing, 2016, 37(2): 356-369.

DOI：10.1080/01431161.2015.1125557

The Suomi National Polar-orbiting Partnership (NPP) satellite was successfully launched on 28 October 2011. The on-board Cross-track Infrared Sounder (CrIS) provides the hyperspectral infrared radiance covering a spectral range of 3.92-15.4 mu m, inheriting the task to improve numerical weather prediction (NWP) from previous hyperspectral sounders. The so-called sun glint effect results in large biases in CrIS shortwave surface channels near 3.7 mu m and therefore impedes the usage of those channels in the operational data assimilation, because the data biases are required to be evaluated appropriately by any data assimilation system. This work assesses the sun glint effect on bias characteristics of those shortwave surface channels near 3.7 mu m, with the help of a sun glint model developed in the community radiative transfer model (CRTM). It is demonstrated that the daytime biases of those shortwave surface channels are decreased markedly after applying sun glint correction with values close to 0 K. The dependence of daytime biases on sensor zenith angles is also eliminated by using the sun glint model. It is seen that the differences between daytime and night-time biases can reach 0.6 K near mid-latitudes in the southern hemisphere after including the sun glint effect, which implies that the sun glint model needs further enhancement. Overall, the direct assimilation of CrIS shortwave surface channels near 3.7 mu m is possibly accomplished by utilizing the sun glint model implemented in CRTM during both daytime and night-time.

• 出版日期2016