[A-CG38] Satellite Earth Environment Observation

[ACG38-11] Evaluation of SGLI cloud products using SKYNET surface observation data

*Pradeep Khatri¹, Tadahiro Hayasaka¹, Hitoshi Irie², Husi Letu³, Takashi Nakajima⁴, Hiroshi Ishimoto⁵, Tamio Takamura² (1.Center for Atmospheric and Oceanic Studies,Tohoku University, 2.Center for Environmental Remote Sensing, Chiba University, Chiba, Japan, 3.Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing, China, 4.Research and Information Center (TRIC), Tokai University, Hiratsuka, Japan, 5.Meteorlogical Research Institute, Tsukuba, Japan)

Keywords:SGLI , Cloud product, SKYNET, quality assessment, global irradiance

This study uses data about clouds and global irradiances observed from the Earth’s surface using a sky radiometer and a pyranometer, respectively, belonging to SKYNET to understand the quality of the two most fundamental cloud properties—cloud optical depth (COD) and cloud-particle effective radius (CER)—of both water and ice clouds. The SGLI-observed COD agrees well with values observed from the surface, although it agrees better for water clouds than for ice clouds, while the SGLI-observed CER exhibits poorer agreement than does the COD, with the SGLI values being generally higher than the sky radiometer values. These comparisons between the SGLI and sky radiometer cloud properties are found to differ for different cloud types of both the water and ice cloud phases and different solar and satellite viewing angles by agreeing better for relatively uniform and flat cloud type and for relatively low solar zenith angle. Furthermore, it is found that the SGLI-observed cloud properties reproduce global irradiances quite satisfactorily for both water and ice clouds by resembling several important features of the COD comparison, such as the better agreement for water clouds than for ice clouds and the tendency to underestimate (resp. overestimate) the COD in SGLI observations for optically thick (resp. thin) clouds.