Cirrus Cloud Radiative Forcing Derived from Synergetic Use of MODIS Analyses and Ground-Based Observations

We have been performing radiative budget measurements at a ground-based observatory located on Fukue Island. In this study, we analyzed the data from instruments installed in the observatory and the data observed by MODIS, the satellite-borne imager, to evaluate cirrus cloud radiative forcing (CRF). The result shows that CRF took a large positive value as 127.98 W m-2 at the top of the atmosphere (TOA) and a small positive value as 13.2 W m-2 at the surface. As a result, it was found that optically very thin cirrus clouds exert a strong warming effect on the Earth's system and a weak warming effect on the Earth's surface when aerosols are not taken into account.