Holocene climate forcings and lacustrine regime shifts in the Indian summer monsoon realm
Holocene climate forcings and lacustrine regime shifts in the Indian summer monsoon realm
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DOI：
10.1002/esp.5004
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发表时间：
2020-09
影响因子：
3.3
通讯作者：
Sushma Prasad;N. Marwan;Deniz Eroglu;B. Goswami;P. Mishra;B. Gaye;A. Anoop;N. Basavaiah;M. Stebich;A. Jehangir
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作者：
Sushma Prasad;N. Marwan;Deniz Eroglu;B. Goswami;P. Mishra;B. Gaye;A. Anoop;N. Basavaiah;M. Stebich;A. Jehangir
极端气候事件已经在印度夏季风（ISM）领域的气象和长期代理记录中得到确认。然而，古气候数据在理解长时间尺度上引发极端气候的机制方面的潜力尚未得到充分利用。区分指示气候变化、环境和生态系统变化的代用物对于与强迫机制（例如El‐Niño南方涛动）进行比较至关重要。在这项研究中，我们使用数据分析技术[多重递归网络（MRN）和主成分分析（PCA）]对位于不同气候区域的两个湖泊的多代理数据进行解耦合，这两个湖泊分别是Lonar湖（ISM主导）和高海拔Tso Moriri湖（ISM和西风带影响）。结果表明：(1)作为环境条件变化指标的MRN分析在气候驱动因素单一的地区与干旱相关，但在气候/环境驱动因素多的地区结果不明确；（ii）全新世早期湿润期湖泊生态系统对强迫“不太敏感”；(3)单一气候驱动因子的气候带档案对状态变化最为敏感；（iv）数据分析成功地确定了气候变化开始的时间，并通过与强迫机制的比较区分了外在和内在（湖泊）变化。我们的研究结果有助于开发概念模型来解释强迫与区域气候变化之间的联系，这些模型可以在气候模型中进行测试，从而更好地理解ISM动力学及其对生态系统的影响。©2020 John Wiley & Sons, Ltd
Extreme climate events have been identified both in meteorological and long‐term proxy records from the Indian summer monsoon (ISM) realm. However, the potential of palaeoclimate data for understanding mechanisms triggering climate extremes over long time scales has not been fully exploited. A distinction between proxies indicating climate change, environment, and ecosystem shift is crucial for enabling a comparison with forcing mechanisms (e.g. El‐Niño Southern Oscillation). In this study we decouple these factors using data analysis techniques [multiplex recurrence network (MRN) and principal component analyses (PCA)] on multiproxy data from two lakes located in different climate regions – Lonar Lake (ISM dominated) and the high‐altitude Tso Moriri Lake (ISM and westerlies influenced). Our results indicate that (i) MRN analysis, an indicator of changing environmental conditions, is associated with droughts in regions with a single climate driver but provides ambiguous results in regions with multiple climate/environmental drivers; (ii) the lacustrine ecosystem was ‘less sensitive’ to forcings during the early Holocene wetter periods; (iii) archives in climate zones with a single climate driver were most sensitive to regime shifts; (iv) data analyses are successful in identifying the timing of onset of climate change, and distinguishing between extrinsic and intrinsic (lacustrine) regime shifts by comparison with forcing mechanisms. Our results enable development of conceptual models to explain links between forcings and regional climate change that can be tested in climate models to provide an improved understanding of the ISM dynamics and their impact on ecosystems. © 2020 John Wiley & Sons, Ltd.