AHI-Derived Daytime Cloud Optical/Microphysical Properties and Their Evaluations With the Collection-6.1 MOD06 Product

Cloud optical/microphysical properties (COMPs) with a high spatiotemporal resolution are required for monitoring the evolution of convective clouds, studying aerosol–cloud–precipitation interactions, and evaluating cloud microphysics parameterization schemes in weather and climate models. This study applied the bispectral method, commonly used for COMP retrievals, to Advanced Himawari Imager (AHI)/Himawari-8 observations. The AHI daytime cloud optical thickness ( $\tau$ ) and cloud-top particle effective radius ( Re ) retrievals were then evaluated with the Collection-6.1 Moderate Resolution Imaging Spectroradiometer cloud product (MOD06) for a three-month period from June 1, 2017, to August 31, 2017. Overall, the AHI-retrieved COMP results are in good agreement with the MOD06 product. The correlation coefficients of $\tau $ and Re between the AHI retrievals and MOD06 products are 0.76–0.89 and 0.63–0.87, respectively. Overestimations are mainly observed in the 1.6- $\mu \text{m}$ Re (Re1.6) and ice-phase 3.9- $\mu \text{m}$ Re (Re3.9) retrievals. There are $\tau $ dependencies in the retrieval biases of $\tau $ and Re1.6, as well as angular dependencies in the retrieval biases of $\tau $ and ice-phase Re3.9. Moreover, the monthly mean composites for three COMP retrievals from the MOD06 and AHI algorithms are compared. Significant differences are only found between the two Re1.6 products. This study also finds that AHI-retrieved Re and $\tau $ values have a diurnal variation over land but not over oceans.