Regional Study on the Oceanic Cool Skin and Diurnal Warming Effects: Observing and Modeling

Abstract

The cool skin and diurnal warming effects are important factors affecting the vertical temperature gradient in the upper ocean. Accurately understanding skin effects is of great significance for studying ocean–atmosphere modeling and climate change. The skin models need to be validated for their applicability under different oceanic conditions to improve their accuracy. Shipboard measurements from August 2015 to October 2018 in the Northwest Pacific Ocean are used to validate some of the current models. The results show that the Tropical Ocean-Global Atmosphere (TOGA) Coupled Ocean–Atmosphere Response Experiment (COARE) cool skin model obtains a mean cool skin value of −0.25 K, which is close to the averaged observed value of −0.23 K. A significant positive correlation between the sea–air temperature difference and the amplitude of the cool skin effect is observed in this study. Three diurnal warming models are discussed and compared. The profiles of ocean surface heating (POSH) model performed the best and was the closest one to the observation. The mean temperature differences bewteen the COARE and POSH models are close to 0 K, while the other model shows the overestimation with a mean temperature difference of 0.21 K. The measurements and validations of the thermal skin effects in this study can be useful for regional research on the air–sea interaction and upper ocean gradients.