On the importance of the atmospheric coupling to the small-scale ocean in the modulation of latent heat flux

In this study, ocean and atmosphere satellite observations, an atmospheric reanalysis a set of regional numerical simulations the lower are used to assess coupling between sea-surface temperature (SST) marine boundary layer (MABL) as well latent heat flux (LHF) sensitivity SST in north-west tropical Atlantic Ocean. The results suggest that SST-MABL depends on spatial scale interest. At scales larger than mesoscale (larger 150 km), negative correlations observed near-surface wind speed (U 1 0m ) positive specific humidity (q 2m SST. However, when smaller (1 – km, i.e., encompassing portion submesoscale) considered, U 10 m -SST correlate inversely q relation significantly differs from what is expected using Clausius-Clapeyron equation. This interpreted terms active modifying state, driving convection, mixing entrainment air free troposphere into MABL. estimated values ocean-atmosphere at small-scale then develop linear SST-based downscaling method aiming include further investigate impact these fine-scale features available low-resolution data set. show they induce significant increase LHF (30% 40% per °C SST). We identify two mechanisms causing such large LHF: (1) thermodynamic contribution only includes with SSTs associated dependence saturating water vapor pressure (2) dynamical related change vertical stratification MABL consequence anomalies. Using different setups, we conclude largest comes dynamic mode (28% against 5% for mode). To validate our approach results, have implemented high-resolution WRF forced by analyzed same algorithm. estimate biases reduced factor 2 applied, providing confidence results.