报告题目：Ocean Current Feedback and the Tropical Pacific Mean State: From Mesoscale Eddies to the Walker Circulation

报告专家：Julien Boucharel 研究员

报告时间：2026年10月20日（周二）上午10:00

报告地点：气象楼423会议室

主  持 人：陈汉卿 教授

专家简介:

Julien Boucharel 博士，法国国家可持续发展研究院（IRD）研究员，任职于法国图卢兹地球物理与空间海洋学实验室（LEGOS）。主要研究方向包括热带气候变率、ENSO动力学及多样性、非线性气候过程与全球遥相关，以及大尺度气候模态与热带气旋、海洋波动和海岸过程的相互作用，重点关注气候变率对海岸侵蚀、洪涝及海岸灾害风险的影响。

报告摘要：

The equatorial Pacific zonal SST gradient anchors the Walker circulation and ENSO, yet remains poorly represented in coupled models. Using 40-year, eddy-rich coupled CROCO–WRF simulations, this study examines the impacts of current feedback (CFB) on tropical Pacific climate. Part I shows that CFB reduces wind energy input by ~65%, weakens the South Equatorial Current, strengthens the Equatorial Undercurrent, and shoals the thermocline by ~10 m. This produces a La Niña-like response, with eastern cooling, western warming, and a ~12% stronger zonal SST gradient. Eastern cooling arises from reduced heat advection through Tropical Instability Wave damping (“eddy killing”), while western warming reflects weaker vertical mixing. Part II shows that the stronger SST gradient intensifies the Walker and Hadley circulations, shifts the Hadley ascending branch northward, and reorganizes tropical precipitation, strengthening the ITCZ and producing an eastern Pacific meridional dipole. Moisture budget analysis identifies mean circulation changes as the primary driver. These findings suggest that neglecting CFB may contribute to persistent equatorial Pacific biases in coarse-resolution climate models.

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2026.10.15