The thermodynamic state of the Arctic atmosphere observed by AIRS: comparisons during the record minimum sea ice extents of 2007 and 2012
The thermodynamic state of the Arctic atmosphere observed by AIRS: comparisons during the record minimum sea ice extents of 2007 and 2012
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DOI：
10.5194/acp-13-7441-2013
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发表时间：
2013-08
影响因子：
6.3
通讯作者：
A. Devasthale;J. Sedlar;T. Koenigk;E. Fetzer
中科院分区：
文献类型：
--
作者：
A. Devasthale;J. Sedlar;T. Koenigk;E. Fetzer
抽象。2007年和2012年夏季在北极观测到的海冰最小范围（SIM）是过去十年海冰加速消失的明显证据。提高我们对北极大气层的了解并对其特征进行准确量化变得越来越重要，尤其是为了改善对未来此类极端事件的预测。在这方面，美国宇航局Aqua卫星上的大气红外探测仪（AIRS）仪器提供了至关重要的见解，因为它能够提供关于大气热力学的三维信息。在这里，我们促进在这两个SIM事件期间，使用长达十年的AIRS观测记录（2003-2012）的北极大气的热力学状态的演变进行比较。结果表明，2012年海冰融化的气象条件并不极端，但冬季至初夏的3个预处理因子对海冰融化起着重要的促进作用。首先，2012年整个冬季和早春，沿欧亚大陆中部和北大西洋部分的边缘海冰区沿着保持温暖，防止了更厚的冰堆积。第二，与2007年相比，2012年春末夏初的环流模式有利于海冰从北极向大西洋地区的有效输送。第三，从5月开始，加拿大群岛和东南部博福特海的额外变暖进一步加速了海冰的融化。所有这些因素都可能导致已经很薄且不断减少的海冰覆盖面低于2007年以前的海冰最小范围。与2007年形成鲜明对比的是，2012年夏季在东西伯利亚海和楚科奇海观测到负表面温度异常和云量增加。结果表明，基于卫星的大气预处理监测可能是预测北极极端海冰融化事件的重要信息来源。
Abstract. The record sea ice minimum (SIM) extents observed during the summers of 2007 and 2012 in the Arctic are stark evidence of accelerated sea ice loss during the last decade. Improving our understanding of the Arctic atmosphere and accurate quantification of its characteristics becomes ever more crucial, not least to improve predictions of such extreme events in the future. In this context, the Atmospheric Infrared Sounder (AIRS) instrument onboard NASA's Aqua satellite provides crucial insights due to its ability to provide 3-D information on atmospheric thermodynamics. Here, we facilitate comparisons in the evolution of the thermodynamic state of the Arctic atmosphere during these two SIM events using a decade-long AIRS observational record (2003–2012). It is shown that the meteorological conditions during 2012 were not extreme, but three factors of preconditioning from winter through early summer played an important role in accelerating sea ice melt. First, the marginal sea ice zones along the central Eurasian and North Atlantic sectors remained warm throughout winter and early spring in 2012 preventing thicker ice build-up. Second, the circulation pattern favoured efficient sea ice transport out of the Arctic in the Atlantic sector during late spring and early summer in 2012 compared to 2007. Third, additional warming over the Canadian archipelago and southeast Beaufort Sea from May onward further contributed to accelerated sea ice melt. All these factors may have lead the already thin and declining sea ice cover to pass below the previous sea ice extent minimum of 2007. In sharp contrast to 2007, negative surface temperature anomalies and increased cloudiness were observed over the East Siberian and Chukchi seas in the summer of 2012. The results suggest that satellite-based monitoring of atmospheric preconditioning could be a critical source of information in predicting extreme sea ice melting events in the Arctic.