Global Spatial and Temporal Variability of the Oceanic Cool Skin Effect

Abstract The oceanic cool skin effect is characterized by a temperature depression between the ocean's submillimeter thermal skin layer (SST skin ) and the underlying water (SST depth ). This study evaluates the ability of the widely used Fairall et al. (1996), https://doi.org/10.1029/95jc03190 model (F96) to simulate the cool skin effect using surface forcing data from the Modern‐Era Retrospective analysis for Research and Applications, Version 2 (MERRA‐2), validated against high‐accuracy infrared radiometric measurements from the Marine‐Atmospheric Emitted Radiance Interferometer (M‐AERI) and the Infrared Sea Surface Temperature Autonomous Radiometer (ISAR) collected during research cruises spanning diverse oceanic regions. Results show that F96 model simulations driven by MERRA‐2 inputs generally match the observed skin effects, with mean biases of −0.03 to −0.04 K and standard deviations ∼0.1 K, attributed primarily to uncertainties in humidity, longwave radiative flux, and wind speed. A 24‐year global analysis (2000–2023) revealed a mean cool skin effect of approximately −0.2 K, with pronounced spatial and seasonal variability. Strongest cooling (−0.3 K or more) occurs in regions such as western boundary currents during colder months, while the Southern Ocean shows much weaker skin effects (−0.1 K) due to persistent high wind speeds and reduced net heat loss. These results suggest that the commonly applied constant correction of −0.17 K in satellite SST skin retrievals does not accurately represent the true magnitude and variability of the cool skin effect. A more accurate correction scheme incorporating latitude and seasonal dependence is recommended to improve the accuracy of satellite‐derived SST skin fields, and better support climate model applications.