Atmospheric impacts of Arctic sea-ice loss, 1979-2009: separating forced change from atmospheric internal variability
Atmospheric impacts of Arctic sea-ice loss, 1979-2009: separating forced change from atmospheric internal variability
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DOI：
10.1007/s00382-013-1830-9
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发表时间：
2014-07-01
期刊：
影响因子：
4.6
通讯作者：
Tomas, Robert
中科院分区：
文献类型：
--
作者：
Screen, James A.;Deser, Clara;Tomas, Robert
北极海冰覆盖的持续减少对更广泛的气候系统产生了影响。海冰损失对大气影响的检测和重要性部分取决于海冰强迫变化与自然大气内部变率（AIV）相比的相对幅度。本研究分析了两个独立的大气环流模型的大合奏，以分离的被迫响应历史北极海冰损失（1979-2009年）从AIV，并量化信噪比。我们还提出了一个模拟结果与海冰强迫大约增加了一倍的幅度。在接近海冰损失的地区，我们确定了统计上显着的近地表大气变暖和降水增加，在秋季和冬季两个模型。在冬季，这两个模式表现出显着降低的海平面气压和位势高度在北极。所有这些反应大致相似，但加强和/或更广泛的地理，当海冰强迫的大小增加一倍。信号噪声比在变量和位置之间差异很大。温度和降水响应比海平面气压或位势高度响应更容易检测（信噪比更高）。同样，本地响应（即，在海冰损失附近）比中纬度或高层响应更容易检测。基于我们对信噪比的估计，我们推测当地近地表温度和降水对过去北极海冰损失的响应超过了AIV，并且在观测记录中可以检测到，但是潜在的大气环流、高层和远程响应可能部分或全部被AIV掩盖。
The ongoing loss of Arctic sea-ice cover has implications for the wider climate system. The detection and importance of the atmospheric impacts of sea-ice loss depends, in part, on the relative magnitudes of the sea-ice forced change compared to natural atmospheric internal variability (AIV). This study analyses large ensembles of two independent atmospheric general circulation models in order to separate the forced response to historical Arctic sea-ice loss (1979-2009) from AIV, and to quantify signal-to-noise ratios. We also present results from a simulation with the sea-ice forcing roughly doubled in magnitude. In proximity to regions of sea-ice loss, we identify statistically significant near-surface atmospheric warming and precipitation increases, in autumn and winter in both models. In winter, both models exhibit a significant lowering of sea level pressure and geopotential height over the Arctic. All of these responses are broadly similar, but strengthened and/or more geographically extensive, when the sea-ice forcing is doubled in magnitude. Signal-to-noise ratios differ considerably between variables and locations. The temperature and precipitation responses are significantly easier to detect (higher signal-to-noise ratio) than the sea level pressure or geopotential height responses. Equally, the local response (i.e., in the vicinity of sea-ice loss) is easier to detect than the mid-latitude or upper-level responses. Based on our estimates of signal-to-noise, we conjecture that the local near-surface temperature and precipitation responses to past Arctic sea-ice loss exceed AIV and are detectable in observed records, but that the potential atmospheric circulation, upper-level and remote responses may be partially or wholly masked by AIV.