中国海洋大学吴立新课题组取得一项新突破。他们的研究认为地转流控制着海洋东部边界上升流的未来变化。相关论文于2023年1月30日发表在《自然—气候变化》杂志上。

该研究组使用高分辨率气候模拟改进的东部边界上升流的集合，研究表明，在高排放情景下，东部边界上升流系统的上升流长期变化与基于风的上升流指数推断的变化有很大不同。具体来说，减弱或不变的上升流可以与增强的上升流有利风相吻合。这些差异与地转流的长期变化有关，地转流主导了加那利流和本格拉流的上升流变化，并强烈抵消了加利福尼亚流和洪堡洋流的风驱动变化。研究结果强调了地转流在温室效应下对东部边界上升流趋势的控制作用，而Bakun的假设忽略了这一点。

据悉，主要的东部边界上升流系统(EBUSs)上空的赤道向沿岸风，通过埃克曼动力学驱动强烈的上升流，使营养丰富的深水浮出水面，促进海洋初级生产和渔业。从追溯到Bakun的假设开始，人们普遍认为，温室效应通过增强有利于上升流的风来增强东部边界的上升流;然而，这一点还没有得到验证。

附：英文原文

Title: Geostrophic flows control future changes of oceanic eastern boundary upwelling

Author: Jing, Zhao, Wang, Shengpeng, Wu, Lixin, Wang, Hong, Zhou, Shenghui, Sun, Bingrong, Chen, Zhaohui, Ma, Xiaohui, Gan, Bolan, Yang, Haiyuan

Issue&Volume: 2023-01-30

Abstract: Equatorward alongshore winds over major eastern boundary upwelling systems (EBUSs) drive intense upwelling via Ekman dynamics, surfacing nutrient-rich deep waters and promoting marine primary production and fisheries. It is generally thought, dating back to Bakun’s hypothesis, that greenhouse warming should enhance upwelling in EBUSs by intensifying upwelling-favourable winds; yet this has not been tested. Here, using an ensemble of high-resolution climate simulations with improved EBUS representation, we show that long-term upwelling changes in EBUSs differ substantially, under a high-emission scenario, from those inferred by the wind-based upwelling index. Specifically, weakened or unchanged upwelling can coincide with intensified upwelling-favourable winds. These differences are linked to long-term changes of geostrophic flows that dominate upwelling changes in the Canary and Benguela currents and strongly offset wind-driven changes in the California and Humboldt currents. Our results highlight the controlling role of geostrophic flows in upwelling trends in EBUSs under greenhouse warming, which Bakun’s hypothesis overlooked.

DOI: 10.1038/s41558-022-01588-y

Source: https://www.nature.com/articles/s41558-022-01588-y