Fu Shuo, Hu Shineng, Zheng Xiao-Tong, McMonigal Kay, Larson Sarah, Tian Yiqun
Frontier Science Center for Deep Ocean Multispheres and Earth System (FDOMES) and Physical Oceanography Laboratory, Ocean University of China, Qingdao, China.
Division of Earth and Climate Sciences, Nicholas School of the Environment, Duke University, Durham, NC, USA.
Nat Commun. 2024 Feb 20;15(1):1562. doi: 10.1038/s41467-024-45677-2.
The tropical Pacific warming pattern since the 1950s exhibits two warming centers in the western Pacific (WP) and eastern Pacific (EP), encompassing an equatorial central Pacific (CP) cooling and a hemispheric asymmetry in the subtropical EP. The underlying mechanisms of this warming pattern remain debated. Here, we conduct ocean heat decompositions of two coupled model large ensembles to unfold the role of wind-driven ocean circulation. When wind changes are suppressed, historical radiative forcing induces a subtropical northeastern Pacific warming, thus causing a hemispheric asymmetry that extends toward the tropical WP. The tropical EP warming is instead induced by the cross-equatorial winds associated with the hemispheric asymmetry, and its driving mechanism is southward warm Ekman advection due to the off-equatorial westerly wind anomalies around 5°N, not vertical thermocline adjustment. Climate models fail to capture the observed CP cooling, suggesting an urgent need to better simulate equatorial oceanic processes and thermal structures.
自20世纪50年代以来，热带太平洋的变暖模式在西太平洋（WP）和东太平洋（EP）呈现出两个变暖中心，包括赤道中部太平洋（CP）的冷却以及亚热带东太平洋的半球不对称性。这种变暖模式的潜在机制仍存在争议。在此，我们对两个耦合模式大集合进行海洋热分解，以揭示风驱动海洋环流的作用。当风的变化受到抑制时，历史辐射强迫会导致亚热带东北太平洋变暖，从而造成一种向热带西太平洋延伸的半球不对称性。相反，热带东太平洋的变暖是由与半球不对称性相关的跨赤道风引起的，其驱动机制是由于北纬5°附近的赤道外西风异常导致的向南温暖埃克曼平流，而非垂直温跃层调整。气候模型未能捕捉到观测到的赤道中部太平洋冷却现象，这表明迫切需要更好地模拟赤道海洋过程和热结构。
