近日，香港科技大学苏慧团队报道了2025年北极海冰范围创纪录低值：拉尼娜与南印度洋暖异常的双重强迫。该项研究成果发表在2026年10月27日出版的《国家科学评论》杂志上。

2025年2—3月，北极经历了创纪录的低海冰范围，尽管海冰损失在过去十年有所放缓。虽然当时存在一次弱拉尼娜事件，但其影响本身不足以解释这一极端事件。

研究组证明，这一年际尺度上的创纪录低值是由拉尼娜与同期南印度洋暖异常（SIOW）的协同效应驱动的。拉尼娜扰动了沃克环流，而SIOW改变了哈德莱环流。二者在热带印度洋上的联合强迫产生了强烈的异常下沉运动和高层辐合，激发了一支向东北传播的罗斯贝波。该波列在鄂霍次克海上空产生了显著的反气旋异常，提高了气温并加速了海冰融化。该发现揭示了一条由拉尼娜和SIOW引发的跨海盆大气桥，确立了印度洋—太平洋协同强迫在驱动北极海冰极端损失中的关键作用，而这一损失叠加在长期下降趋势之上。

附：英文原文

Title: The 2025 Record Low in Arctic Sea Ice Extent: Dual Forcing from La Nia and Southern Indian Ocean Warm Anomaly

Author: Wang, Cen, Su, Hui, Zhai, Chengxing, Zheng, Jianqiu, Yu, Shiwei, Mo, Huisi, Xu, Luancheng, Du, Shuangchen, Huo, Jianan

Issue&Volume: 2026-10-27

Abstract: In February-March 2025, the Arctic experienced record-low sea ice extent, despite a decadal slowdown in ice loss [1,2]. Although a weak La Nia was present, its influence alone is insufficient to explain this extreme event. Here, we demonstrate that this record low on an interannual scale was driven by the synergistic effects of La Nia and concurrent South Indian Ocean warm anomaly (SIOW). La Nia perturbed the Walker circulation, while SIOW altered the Hadley Cell. Their combined forcing over the tropical Indian Ocean generated intense anomalous downward motion and upper-level convergence, exciting a northeast-propagating Rossby wave. This wave train produced a significant anticyclonic anomaly over the Okhotsk Sea, which enhanced air temperature and accelerated sea ice melt. Our findings reveal an inter-basin atmospheric bridge, initiated by La Nia and SIOW, establishing the essential role of synergistic Indo-Pacific forcing in driving extreme Arctic sea ice loss, superimposed on a longterm decline.

DOI: 10.1093/nsr/nwag676

Source:https://dx.doi.org/10.1093/nsr/nwag676