Glacial North Atlantic: Sea-surface conditions reconstructed by GLAMAP 2000
Glacial North Atlantic: Sea-surface conditions reconstructed by GLAMAP 2000
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DOI：
10.1029/2002pa000774
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发表时间：
2003-09
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通讯作者：
U. Pflaumann;M. Sarnthein;M. Chapman;L. d'Abreu;B. Funnell;M. Huels;T. Kiefer;M. Maslin;H. Sch
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文献类型：
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作者：
U. Pflaumann;M. Sarnthein;M. Chapman;L. d'Abreu;B. Funnell;M. Huels;T. Kiefer;M. Maslin;H. Sch
热带海洋对全球气候变化的响应以及北欧冰川海海冰的范围属于古气候学中的重大争议。我们的新重建的峰值冰川海表面温度（SST）在大西洋是基于南极有孔虫的普查计数，使用最大相似性技术版本28（SIMMAX-28）的现代模拟技术与947现代模拟样品和119个良好的沉积物岩心。我们的研究比较了两个略有不同的情况下，末次冰期最大（LGM），冰河时代的环境过程：土地，海洋，冰川（EPILESS）和冰川大西洋测绘（GLAMAP 2000）的时间切片。结果表明，末次盛冰期南半球最大冷却略早于北半球。在这两个时间片海冰仅限于西北边缘的北欧海在冰川北方夏季，而中部和东部地区是无冰的。在北方的冰川冬季，海冰向冰岛和法罗群岛的南部推进。在北大西洋北方中部，北纬45度到60度之间形成了一个反气旋环流，在爱尔兰以西形成了一个冷水团，那里的冰川冷却最高达到了12摄氏度。在亚热带海洋环流中，新的重建支持气候变化监测和评估方案项目成员（CLIMAP）[1981]所示的冰间冰期SST的稳定性。最小SST季节变化的纬向带位于北纬20度至60度之间，表明末次盛冰期的热量赤道与今天的纬度相同。与CLIMAP重建的结果相反，在北方半球夏季，热带东大西洋上升流带的冰川冷却达到6 - 8 ℃。这些SIMMAX为基础的和公布的U37（k）和Mg/Ca为基础的赤道SST记录之间的差异归因于强SST的季节性和SST信号，产生不同的南极物种组在不同的季节。
The response of the tropical ocean to global climate change and the extent of sea ice in the glacial nordic seas belong to the great controversies in paleoclimatology. Our new reconstruction of peak glacial sea surface temperatures (SSTs) in the Atlantic is based on census counts of planktic foraminifera, using the Maximum Similarity Technique Version 28 (SIMMAX-28) modern analog technique with 947 modern analog samples and 119 well-dated sediment cores. Our study compares two slightly different scenarios of the Last Glacial Maximum (LGM), the Environmental Processes of the Ice Age: Land, Oceans, Glaciers (EPILOG), and Glacial Atlantic Ocean Mapping (GLAMAP 2000) time slices. The comparison shows that the maximum LGM cooling in the Southern Hemisphere slightly preceeded that in the north. In both time slices sea ice was restricted to the north western margin of the nordic seas during glacial northern summer, while the central and eastern parts were ice-free. During northern glacial winter, sea ice advanced to the south of Iceland and Faeroe. In the central northern North Atlantic an anticyclonic gyre formed between 45degrees and 60degreesN, with a cool water mass centered west of Ireland, where glacial cooling reached a maximum of >12degreesC. In the subtropical ocean gyres the new reconstruction supports the glacial-to-interglacial stability of SST as shown by CLIMAP Project Members (CLIMAP) [1981]. The zonal belt of minimum SST seasonality between 2degrees and 6degreesN suggests that the LGM caloric equator occupied the same latitude as today. In contrast to the CLIMAP reconstruction, the glacial cooling of the tropical east Atlantic upwelling belt reached up to 6degrees-8degreesC during Northern Hemisphere summer. Differences between these SIMMAX-based and published U37(k)- and Mg/Ca-based equatorial SST records are ascribed to strong SST seasonalities and SST signals that were produced by different planktic species groups during different seasons.