Cloud‐fraction‐dependent bias in satellite liquid water path retrievals of shallow, non‐precipitating marine clouds

This study compares Wentz microwave liquid water path retrievals with MODIS and MISR optical estimates in shallow, non‐precipitating marine clouds. In overcast conditions, the microwave and optical estimates are comparable; however, as cloud fraction decreases microwave retrievals strongly and increasingly overestimate optical ones. This positive microwave bias cannot be explained neither by the elimination of negative values in the operational Wentz dataset, nor by the somewhat reduced sensitivity of MODIS cloud detection to small clouds.