Vertical-Homogeneity Assumption Causing Inconsistency Between Visible- and Infrared-Based

A possible cause of radiative inconsistency between visible- and infrared (IR)-based optical properties is examined and corrected for. This study is motivated by significant IR modeling biases of around −7 K found in our previous study. In that study, the model simulation was conducted using cloud optical thickness (COT) and effective radius retrieved from the ModerateResolution Imaging Spectroradiometer, and cloud top and base heights measured by CloudSat. For single-layered and relatively optically thick clouds (COT > 10), uncertainties in the COT and effective radius are shown to have a small contribution to the IR modeling biases; making an assumption that the clouds are vertically homogeneous seems to cause most of the IR modeling biases. By creating a cloud extinction profile from the CloudSat data, IR modeling biases are reduced to −2 K instead of −7 K.