Using observations and CMIP6 historical simulations, the seasonal responses of Southern Ocean (50°S–70°S) sea surface temperature (SST) to Southern Annular Mode (SAM) variations are investigated in this study. The results suggest that the averaged Southern Ocean SST in austral spring and summer show a significant cooling in response to a positive SAM, while the responses in austral autumn and winter are negligible. The cooling effect is resulted from the cold water in higher latitudes and deeper oceans brought by the equatorward Ekman transport and the Ekman pumping associated with the positive SAM. Among CMIP6 models, the magnitude of the simulated cooling response connects to the climatological meridional and vertical ocean temperature gradients, and the magnitude of Ekman motion in response to SAM. In addition, the spring and summer SAM plays a more important role in modulating Southern Ocean SST in autumn and winter than the autumn and winter SAM.

中文翻译：

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评估 CMIP6 模型中南大洋海面温度对南方环模的季节响应


本研究利用观测数据和 CMIP6 历史模拟，研究了南大洋 (50°S–70°S) 海面温度 (SST) 对南方环模 (SAM) 变化的季节性响应。结果表明，南大洋春季和夏季的平均海表温度在 SAM 正值的响应下表现出显着的变冷，而南大洋秋季和冬季的响应可以忽略不计。冷却效应是由赤道方向的埃克曼输运和与正SAM相关的埃克曼泵送带来的高纬度和深海冷水造成的。在 CMIP6 模型中，模拟冷却响应的幅度与气候经向和垂直海洋温度梯度以及响应 SAM 的 Ekman 运动幅度相关。此外，春夏季环模对秋冬季南大洋海温的调节作用比秋冬季环模更重要。