Retrieval of Sea Fog Top Height Over the Yellow and Bohai Seas Using Island Elevation

Sea fog strongly affects marine transportation and offshore operations, yet its vertical extent remains difficult to determine over broad ocean areas. Active remote sensing can provide accurate vertical information, but its narrow sampling and low temporal resolution make it unsuitable for continuous, large‐scale monitoring of sea fog top height (SFTH). Existing widely used passive satellite cloud top height (CTH) retrieval methods are not well suited to shallow sea fog. Focusing on the Yellow and Bohai Seas, we present a daytime MODIS‐based method for retrieving SFTH by deriving a linear relationship between sea fog reflectance and SFTH, constrained by island peak elevation. This relationship is approximated by establishing a linear classification model that separates islands embedded in sea fog scenes into two categories, visible and obscured . Across 49 sea fog events satisfying the applicability criteria, the proposed retrieval agrees more closely with CALIOP‐derived SFTH than the operational MODIS CTH product. For the logistic regression implementation, the mean absolute error and root mean square error decrease from about 304 to 376 for MODIS to about 65 and 98 , respectively, while the hit rate, defined as the fraction of samples with absolute errors no greater than 30 , increases from about 4% to 39%. Note that the method requires at least two visible and two obscured islands, without obstruction by overlying clouds.