Tropical hydroclimatic events, characterized by extreme regional rainfall anomalies, were a recurrent feature of marine isotope stages 2–4 and involved some of the most abrupt and dramatic climatic changes in the late Quaternary. These anomalies were pervasive throughout the tropics and resulted from the southward displacement of the Hadley circulation and the Intertropical Convergence Zone (ITCZ) and its associated convective rainfall, modulated by regional factors. Lake sediments, stalagmites, and offshore marine sediments that integrate inland continental conditions provide a comprehensive record of these changes over the past ∼70,000 yr. Vast areas experienced severe drought while other areas recorded greatly increased rainfall. Within the uncertainties of dating, these tropical rainfall anomalies occurred very close in time (±10²–10³ yr) to the deposition of North Atlantic ice-rafted debris (IRD) that defines Heinrich events (HEs). The IRD record is a good proxy for the amount and distribution of additional freshwater forcing which was necessary to bring about a drastic reduction in the Atlantic Meridional Overturning Circulation (AMOC) strength during each HE. As a consequence of this reduction in AMOC and an abrupt expansion in the area of sea-ice, cooling of the North Atlantic and adjacent continents took place, with a rapid atmospheric response involving the southward displacement of the ITCZ and associated rainfall belts. The climatic consequences of this large-scale change in the Hadley circulation, modulated by regional factors, is clearly recorded throughout the tropics as a series of abrupt and extreme hydroclimatic events. Some of the physical mechanisms that may have played a role in those changes are discussed.

中文翻译：

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热带和亚热带地区晚第四纪气候突变：热带水文气候事件 (THE) 的大陆信号

热带水文气候事件以极端区域降雨异常为特征，是海洋同位素第 2-4 阶段的反复出现的特征，涉及第四纪晚期的一些最突然和最剧烈的气候变化。这些异常现象在整个热带地区普遍存在，是由哈德利环流和热带辐合带（ITCZ）及其相关的对流降雨向南移动造成的，受区域因素的影响。结合内陆大陆条件的湖泊沉积物、石笋和近海海洋沉积物提供了过去 70,000 年这些变化的综合记录。广大地区经历了严重干旱，而其他地区的降雨量大大增加。在测年的不确定性范围内，这些热带降雨异常发生的时间非常接近（±10 ² –10³ yr) 到定义海因里希事件 (HE) 的北大西洋冰筏碎片 (IRD) 的沉积。IRD 记录很好地代表了额外淡水强迫的数量和分布，这是在每次 HE 期间大幅降低大西洋经向翻转环流 (AMOC) 强度所必需的。由于 AMOC 的减少和海冰面积的突然扩大，北大西洋和邻近大陆发生了冷却，伴随着涉及 ITCZ 和相关降雨带向南位移的快速大气响应。受区域因素调节的哈德利环流的这种大规模变化的气候后果在整个热带地区被清楚地记录为一系列突然和极端的水文气候事件。