The impact of sea-ice dynamics on the Arctic climate system
The impact of sea-ice dynamics on the Arctic climate system
复制标题
海冰动态对北极气候系统的影响
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
S. Harrison
中科院分区：
文献类型：
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作者：
S. Vavrus;S. Harrison
抽象的。
五个成对的全球气候模式实验，一个与一个冰袋，只响应海冰动力学（TI）和一个包括海冰动力学（DI），被用来调查北极气候海冰运动的敏感性。一系列实验包括北极比今天冷得多（冰川初期，约115，000年前）和比今天热得多（3 × CO2）的情况。海冰运动全年产生的异常温度低于没有冰动力学的模拟，导致温暖情景中北极变暖减少，寒冷情景中北极变冷增加。这些变化反映了大气环流模式的变化：DI模拟有利于流出的北极空气和海冰进入北大西洋，通过促进气旋环流中心在北方欧亚大陆，而TI模拟有利于南流入更温暖的空气从北大西洋，通过促进气旋环流中心在格陵兰岛。成对模拟之间的差异足够大，可以在55°N以北超过19%的陆地面积上产生不同的植被覆盖，导致陆地表面特征的变化足以对气候产生额外的影响。中全新世（6000年前）与古植被重建的DI和TI实验的比较表明，海冰动力学的结合产生了更现实的模拟高纬度气候。在比现代更温暖的DI实验中，海冰异常的空间格局与近几十年来观察到的北冰洋海冰偶极子结构非常相似，这与温室效应已经影响到高纬度地区的观点一致。
Abstract.
Five paired global climate model experiments, one with an ice pack that only responds thermodynamically (TI) and one including sea-ice dynamics (DI), were used to investigate the sensitivity of Arctic climates to sea-ice motion. The sequence of experiments includes situations in which the Arctic was both considerably colder (Glacial Inception, ca 115,000 years ago) and considerably warmer (3 × CO2) than today. Sea-ice motion produces cooler anomalies year-round than simulations without ice dynamics, resulting in reduced Arctic warming in warm scenarios and increased Arctic cooling in cold scenarios. These changes reflect changes in atmospheric circulation patterns: the DI simulations favor outflow of Arctic air and sea ice into the North Atlantic by promoting cyclonic circulation centered over northern Eurasia, whereas the TI simulations favor southerly inflow of much warmer air from the North Atlantic by promoting cyclonic circulation centered over Greenland. The differences between the paired simulations are sufficiently large to produce different vegetation cover over >19% of the land area north of 55°N, resulting in changes in land-surface characteristics large enough to have an additional impact on climate. Comparison of the DI and TI experiments for the mid-Holocene (6000 years ago) with paleovegetation reconstructions suggests the incorporation of sea-ice dynamics yields a more realistic simulation of high-latitude climates. The spatial pattern of sea-ice anomalies in the warmer-than-modern DI experiments strongly resembles the observed Arctic Ocean sea-ice dipole structure in recent decades, consistent with the idea that greenhouse warming is already impacting the high-northern latitudes.