Diatoms and biomarkers evidence for major changes in sea ice conditions prior the instrumental period in Antarctic Peninsula
Diatoms and biomarkers evidence for major changes in sea ice conditions prior the instrumental period in Antarctic Peninsula
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DOI：
10.1016/j.quascirev.2013.07.021
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发表时间：
2013-11-01
影响因子：
4
通讯作者：
Masse, Guillaume
中科院分区：
文献类型：
--
作者：
Barbara, Loic;Crosta, Xavier;Masse, Guillaume
南极半岛（AP）已被确定为地球上变暖最快的地区之一。目前，卫星监测可以详细了解该地区海冰范围和持续时间与大气和海洋环流之间的关系。然而，在过去 30 年来，我们对海洋-冰-大气相互作用的了解仍然相对匮乏。在这里，我们使用两个海洋沉积物多核（分别为 MTC-38C 和 -18A）中的硅藻普查计数和硅藻特异性生物标志物 (HBI) 描述了上个世纪南极半岛西北部和东北部地区的环境条件。硅藻普查计数和 HBI 显示 1935 年至 1950 年间发生了突然变化，其特点是亚太地区两侧的海洋变暖和海冰消退。自 1950 年以来，推断的环境条件并未提供与近期变暖相关的任何趋势的证据，但显示出多年至十年时间尺度上的显着变化。我们认为，上个世纪的多年海冰变化是由近期变暖所迫使的，而年际变化主要受与亚太地区大气低压槽位置和强度相关的天气和区域风场的控制。然而，自过去二十年以来 SAM 的积极变化无法解释本研究中观察到的区域趋势，这可能是由于局部过程对我们的生物代理反应的影响。 (C) 2013 Elsevier Ltd. 保留所有权利。
The Antarctic Peninsula (AP) has been identified as one of the most rapidly warming region on Earth. Satellite monitoring currently allows for a detailed understanding of the relationship between sea ice extent and duration and atmospheric and oceanic circulations in this region. However, our knowledge on ocean-ice-atmosphere interactions is still relatively poor for the period extending beyond the last 30 years. Here, we describe environmental conditions in Northwestern and Northeastern Antarctic Peninsula areas over the last century using diatom census counts and diatom specific biomarkers (HBIs) in two marine sediment multicores (MTC-38C and -18A, respectively). Diatom census counts and HBIs show abrupt changes between 1935 and 1950, marked by ocean warming and sea ice retreat in both sides of the AP. Since 1950, inferred environmental conditions do not provide evidence for any trend related to the recent warming but demonstrate a pronounced variability on pluri-annual to decadal time scale. We propose that multi-decadal sea ice variations over the last century are forced by the recent warming, while the annual-to-decadal variability is mainly governed by synoptic and regional wind fields in relation with the position and intensity of the atmospheric low-pressure trough around the AP. However, the positive shift of the SAM since the last two decades cannot explain the regional trend observed in this study, probably due to the effect of local processes on the response of our biological proxies. (C) 2013 Elsevier Ltd. All rights reserved.