The Role of Horizontal Temperature Advection in Arctic Amplification
The Role of Horizontal Temperature Advection in Arctic Amplification
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DOI：
10.1175/jcli-d-19-0937.1
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发表时间：
2021-01
影响因子：
4.9
通讯作者：
J. P. Clark;V. Shenoy;S. Feldstein;Sukyoung Lee;M. Goss
中科院分区：
文献类型：
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作者：
J. P. Clark;V. Shenoy;S. Feldstein;Sukyoung Lee;M. Goss
使用自组织地图（SOM）检查1990年至2016年冬季（12月至2月）北极表面气温（SAT）趋势。高维 SAT 数据集被简化为九个代表性 SOM 模式，每个模式都表现出约 10 天的去相关时间尺度，并且约 85% 的方差来自季节内时间尺度。每个 SOM 模式发生频率的趋势用于估计与 SOM 模式相关的年代际北极冬季变暖趋势。研究发现，SOM 模式的趋势解释了巴伦支海和喀拉海大约二分之一的 SAT 趋势、巴芬湾周围三分之一的 SAT 趋势以及楚科奇海三分之二的 SAT 趋势。对每个 SOM 模式的热力学能量方程中每一项的综合计算表明，SAT 异常主要通过异常风对气候温度的平流增长。这意味着北极放大的很大一部分是由于大气环流变化驱动的水平温度平流造成的。对表面能量收支的分析表明，皮肤温度异常及其趋势虽然与 SAT 非常相似，但主要是由向下的长波辐射产生的。
The wintertime (December–February) 1990–2016 Arctic surface air temperature (SAT) trend is examined using self-organizing maps (SOMs). The high-dimensional SAT dataset is reduced into nine representative SOM patterns, with each pattern exhibiting a decorrelation time scale of about 10 days and having about 85% of its variance coming from intraseasonal time scales. The trend in the frequency of occurrence of each SOM pattern is used to estimate the interdecadal Arctic winter warming trend associated with the SOM patterns. It is found that trends in the SOM patterns explain about one-half of the SAT trend in the Barents and Kara Seas, one-third of the SAT trend around Baffin Bay, and two-thirds of the SAT trend in the Chukchi Sea. A composite calculation of each term in the thermodynamic energy equation for each SOM pattern shows that the SAT anomalies grow primarily through the advection of the climatological temperature by the anomalous wind. This implies that a substantial fraction of Arctic amplification is due to horizontal temperature advection that is driven by changes in the atmospheric circulation. An analysis of the surface energy budget indicates that the skin temperature anomalies as well as the trend, although very similar to that of the SAT, are produced primarily by downward longwave radiation.