Subsurface Warm Biases in the Tropical Atlantic and Their Attributions to the Role of Wind Forcing and Ocean Vertical Mixing

• DOI: 10.1175/jcli-d-21-0779.1
• Publication Date: 2022-01-06T16:14:02Z
• Authors: Qiushi Zhang; Yuchao Zhu; Rong-Hua Zhang
• Keywords: Forcing (mathematics); Ocean dynamics; Oceanic basin; Ocean observations; Geophysical fluid dynamics

Abstract Realistic ocean subsurface simulations of thermal structure and variation are critically important to success in climate prediction projection; currently, substantial systematic biases still exist the state-of-the-art models. In this paper, tropical Atlantic Ocean (TA) investigated by analyzing from Model Intercomparison Project (OMIP) conducting ocean-only experiments that based on Parallel Program, version 2 (POP2). The prominent almost all OMIP simulations, characterized two warm-bias patches off equator. By groups POP2-based experiments, potential origins explored, including uncertainties wind forcing vertical mixing parameterization, respectively. It is illustrated warm bias near 10°N can be slightly reduced modulating prescribed field, over entire basin significantly reducing background diffusivity interior ways match observations. a heat-budget analysis, it found improved attributed enhanced cooling effect constraining terms observational estimate, implying overestimation primarily responsible for TA. Since simulation very sensitive more accurate representations clearly needed Significance Statement purpose our study analyze characteristics temperature investigate causes biases. This because greatly reduce reliability models projection. significant arise 100–150 m mainly overestimated mixing. Our work highlights highly further research necessary modeling.