Changes in Holocene climate and the intensity of Southern Hemisphere Westerly Winds based on a high-resolution palynological record from sub-Antarctic South Georgia
Changes in Holocene climate and the intensity of Southern Hemisphere Westerly Winds based on a high-resolution palynological record from sub-Antarctic South Georgia
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DOI：
10.1177/0959683614557576
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发表时间：
2015-02
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通讯作者：
Stephanie L. Strother;U. Salzmann;S. Roberts;D. Hodgson;J. Woodward;Wim Van Nieuwenhuyze;E. Verleyen;W. Vyverman;S. Moreton
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作者：
Stephanie L. Strother;U. Salzmann;S. Roberts;D. Hodgson;J. Woodward;Wim Van Nieuwenhuyze;E. Verleyen;W. Vyverman;S. Moreton
亚南极南乔治亚岛位于南半球西风带的核心、南极绕极流与极锋区之间，是研究南半球气候变化的关键区域。在这里，我们展示了来自安年科夫岛扇湖的 5.8 米长的高分辨率花粉记录，该记录以当地副极地植被为主，金合欢属和禾本科植物在过去 7000 年中一直存在。孢粉学和沉积学分析揭示了全新世晚期温暖的“最适宜气候”，温度在 3790 到 2750 cal 之间。年 BP，随后逐渐过渡到凉爽和潮湿的条件。这种冷却被 1670 到 710 卡路里之间稍微温暖的环境条件打断。年 BP 与北半球“中世纪气候异常”部分重叠。从南美洲运来的非本地花粉粒和长距离花粉粒（例如黄毛榉、罗汉松）的增加表明，南乔治亚岛上空较强的南半球西风可能发生在全新世晚期的一些“较冷”阶段，最明显的是在大约 10 世纪到 20 世纪之间。 2210 和 1670 口径年 BP 和 710 cal 之后。年血压。
Sub-Antarctic South Georgia is a key region for studying climate variability in the Southern Hemisphere, because of its position at the core of the Southern Hemisphere Westerly Wind belt and between the Antarctic Circumpolar Current and the Polar Frontal Zone. Here, we present a 5.8-m long high-resolution pollen record from Fan Lake on Annenkov Island dominated by local sub-polar vegetation, with Acaena and Poaceae being present throughout the last 7000 years. Palynological and sedimentological analyses revealed a warm late Holocene ‘climate optimum’ between 3790 and 2750 cal. yr BP, which was followed by a gradual transition to cool and wet conditions. This cooling was interrupted by slightly warmer environmental conditions between 1670 and 710 cal. yr BP that partly overlap with the Northern Hemisphere ‘Medieval Climate Anomaly’. Increases in non-native and long-distance pollen grains transported from South America (e.g. Nothofagus, Podocarpus) indicate that stronger Southern Hemisphere Westerly Winds over South Georgia possibly occurred during some ‘colder’ phases of the late Holocene, most notably between c. 2210 and 1670 cal. yr BP and after 710 cal. yr BP.