Abstract This study presents a stable oxygen isotope record of Indian summer monsoon (ISM) variability using cave speleothem carbonate from Baratang Island (Andaman Islands) encompassing the last millennium (from 10th to 19th century CE). The studied interval encompasses two major climatic events; the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA) as well as the Current Warm Period (CWP). Our data suggest generally higher precipitation during the warm MCA when the ISM was relatively strong, and low precipitation during the cold LIA with a few exceptions when wet conditions prevailed. The Baratang cave record shows greater similarity with the records from the Sahiya and Klang caves, and opposite trends relative to those from the northeastern Himalaya owing to the dipolar nature of ISM precipitation. High-frequency sub-decadal to centennial scale pulses of weakened summer monsoons are observed during 16th to 19th century CE. These phases of weak ISM are correlated with severe droughts and famines in the Indian subcontinent owing to deficient monsoon rainfall, which had pronounced effect on South Asian societies. Spectral analysis suggests a strong periodicity of 190 yr (de Vries cycle) indicating strong influence of solar insolation.

中文翻译：

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安达曼群岛 Baratang Mahadev 洞穴石笋中记录的过去千年印度夏季风变率

摘要 本研究使用来自 Baratang 岛（安达曼群岛）的洞穴洞穴碳酸盐（从公元 10 世纪到 19 世纪）提供了印度夏季风 (ISM) 变化的稳定氧同位素记录。研究的区间包括两个主要的气候事件；中世纪气候异常 (MCA) 和小冰河时代 (LIA) 以及当前暖期 (CWP)。我们的数据表明，当 ISM 相对较强时，温暖的 MCA 期间降水量通常较高，而在寒冷的 LIA 期间降水量较低，但在潮湿条件下盛行时有少数例外。由于 ISM 降水的偶极性质，Baratang 洞穴记录与 Sahiya 和 Klang 洞穴的记录显示出更大的相似性，与喜马拉雅东北部的记录相反。在公元 16 至 19 世纪期间观察到减弱的夏季季风的高频次年代际到百年尺度脉冲。由于季风降雨不足，印度次大陆的这些弱 ISM 阶段与严重干旱和饥荒有关，这对南亚社会产生了显着影响。光谱分析表明 190 年（de Vries 周期）的强周期性表明太阳日射的强烈影响。