Antarctic Elevation Drives Hemispheric Asymmetry in Polar Lapse Rate Climatology and Feedback
Antarctic Elevation Drives Hemispheric Asymmetry in Polar Lapse Rate Climatology and Feedback
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DOI：
10.1029/2020gl088965
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发表时间：
2020-08-28
影响因子：
5.2
通讯作者：
Bitz, C. M.
中科院分区：
文献类型：
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作者：
Hahn, L. C.;Armour, K. C.;Bitz, C. M.
在二氧化碳增加的模拟中，递减率反馈是北极变暖比南极更强烈的主要驱动因素。虽然南极表面海拔与促进南极下降率反馈减弱有关，但海拔影响下降率反馈的机制仍不清楚。在这里，我们认为，在CO(2)强迫下，南极变暖减弱是由于冰盖海拔上方的大气热传输有限和海拔引起的下降风造成的较浅、较不强烈的气候反转。在南极地形平坦的板状海洋模型实验中，更强的气候反演支持更强的递减率反馈和年平均南极变暖，与CO(2)倍增下的北极相当。与北极不同，平坦的南极洲变暖的季节性主要是由负短波云反馈驱动的，它专门抑制夏季变暖，而冬季增强的递减率反馈的贡献较小。
The lapse rate feedback is the dominant driver of stronger warming in the Arctic than the Antarctic in simulations with increased CO2. While Antarctic surface elevation has been implicated in promoting a weaker Antarctic lapse rate feedback, the mechanisms in which elevation impacts the lapse rate feedback are still unclear. Here we suggest that weaker Antarctic warming under CO(2)forcing stems from shallower, less intense climatological inversions due to limited atmospheric heat transport above the ice sheet elevation and elevation-induced katabatic winds. In slab ocean model experiments with flattened Antarctic topography, stronger climatological inversions support a stronger lapse rate feedback and annual mean Antarctic warming comparable to the Arctic under CO(2)doubling. Unlike the Arctic, seasonality in warming over flat Antarctica is mainly driven by a negative shortwave cloud feedback, which exclusively dampens summer warming, with a smaller contribution from the winter-enhanced lapse rate feedback.