Sea Surface Temperature Budget in Indonesia Seas: The Role of Vertical Turbulent Mixing and its East-West Variations
Faisal Amri, Ahmad Eladawy, Takashi Nakamura

Transdisciplinary Science and Engineering Department, Tokyo Institute of Technology, Tokyo, Japan

Abstract

Vertical turbulent mixing, comprising heat and turbulent fluxes, is a key process governing the seawater temperature changes in the vertical direction. In this study, the influence of vertical turbulent mixing on surface layer temperature (i.e., a layer between free-surface to 20 m depth) in Indonesia seas were diagnosed from an eddy-permitting ocean modeling experiment results. The heat flux in the western and eastern Indonesia corresponds with surface layer cooling tendency of -1.11 and -0.24 degC month\(^{-1}\), mainly due to heat loss related to latent heat component. The turbulent flux at the base of the surface layer (i.e., 20 m depth) in western Indonesia and eastern Indonesia seas corresponds to a surface layer warming tendency of +1.14 and +0.26 degC month\(^{-1}\), respectively, counterbalancing the effect of heat flux. The average eddy diffusivity at 20 m depth in Western Indonesia (A\(_{T}\) = 0.040\(\pm\)0.017 m\(^{2}\) s\(^{-1}\)) however, was lower than in Eastern Indonesia (A\(_{T}\) = 0.049\(\pm\)0.042 m\(^{2}\) s\(^{-1}\)) suggesting the determining role of the vertical gradient of the water temperature (i.e., stratification profile) on the overall turbulent flux. Finally, study conducted here emphasizes the potential existence of distinct east-west mechanisms governing sea surface temperature variabilities in the Indonesia seas.

Keywords: Ocean Modeling, Vertical Turbulent Mixing, Sea Surface Temperature, Indonesia Seas

Topic: Ocean-Atmosphere Dynamics