近日，美国科罗拉多大学博尔德分校Pedro N. DiNezio团队揭示了热带对海洋环流减缓的反应增加了未来干旱的风险。2025年7月30日出版的《自然》杂志发表了该成果。

全球变暖下的热带降雨预估仍然高度不确定，这主要是因为气候对大西洋经向翻转环流（AMOC）可能减弱的不明确反应。尽管AMOC的减缓可以显著改变热带降雨模式，但人们对高纬度变化与热带水文气候之间的物理机制知之甚少。

研究组证明AMOC的减速通过高纬度冷却向热带北大西洋的传播，驱动了热带降雨的广泛变化。他们通过气候模型模拟和Heinrich Stadial 1 （HS1）的古气候记录（一个以AMOC明显减弱为标志的过去时期）确定并验证了这一机制。在模型中，盛行东风和西风通过北大西洋热带和亚热带地区产生的冷空气输送，将气候信号传递到太平洋和印度洋。

海气相互作用将这种反应传递到太平洋和印度洋，改变了远至印度尼西亚、热带安第斯山脉和澳大利亚北部的降雨模式。在全球变暖情景下出现了类似的遥相关，产生了一致的多模型热带水文气候变化模式。这些经古数据验证的预测表明，中美洲、亚马逊河流域和西非地区普遍出现干旱，这凸显了脆弱的人类和生态系统面临严重干旱的风险增加。

附：英文原文

Title: Tropical response to ocean circulation slowdown raises future drought risk

Author: DiNezio, Pedro N., Shanahan, Timothy M., Sun, Tianyi, Sun, Chijun, Wu, Xian, Lawman, Allison, Lea, David, Kageyama, Masa, Merkel, Ute, Prange, Matthias, Otto-Bliesner, Bette, Zhang, Xu

Issue&Volume: 2025-07-30

Abstract: Projections of tropical rainfall under global warming remain highly uncertain1,2, largely because of an unclear climate response to a potential weakening of the Atlantic meridional overturning circulation (AMOC)3. Although an AMOC slowdown can substantially alter tropical rainfall patterns4,5,6,7,8, the physical mechanisms linking high-latitude changes to tropical hydroclimate are poorly understood11. Here we demonstrate that an AMOC slowdown drives widespread shifts in tropical rainfall through the propagation of high-latitude cooling into the tropical North Atlantic. We identify and validate this mechanism using climate model simulations and palaeoclimate records from Heinrich Stadial 1 (HS1)—a past period marked by pronounced AMOC weakening9,10. In models, prevailing easterly and westerly winds communicate the climate signal to the Pacific Ocean and Indian Ocean through the transport of cold air generated over the tropical and subtropical North Atlantic. Air–sea interactions transmit the response across the Pacific Ocean and Indian Ocean, altering rainfall patterns as far as Indonesia, the tropical Andes and northern Australia. A similar teleconnection emerges under global warming scenarios, producing a consistent multi-model pattern of tropical hydroclimatic change. These palaeo-validated projections show widespread drying across Mesoamerica, the Amazon and West Africa, highlighting an elevated risk of severe drought for vulnerable human and ecological systems.

DOI: 10.1038/s41586-025-09319-x

Source: https://www.nature.com/articles/s41586-025-09319-x