Asymmetry in the seasonal cycle of Antarctic sea ice driven by insolation
Asymmetry in the seasonal cycle of Antarctic sea ice driven by insolation
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DOI：
10.1038/s41561-022-00913-6
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发表时间：
2022-03
影响因子：
18.3
通讯作者：
L. Roach;I. Eisenman;T. J. W. Wagner;E. Blanchard-Wrigglesworth;C. Bitz
中科院分区：
文献类型：
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作者：
L. Roach;I. Eisenman;T. J. W. Wagner;E. Blanchard-Wrigglesworth;C. Bitz
南极海冰面积的平均季节周期是不对称的，冰退缩期比冰前进期大约短2个月。这一特征在年复一年和不同卫星产品的观测中基本一致。从CMIP3到CMIP6的几代综合气候模式也广泛再现了这种不对称性，内部变率的影响有限。利用一系列复杂程度不同的理想气候模式，我们发现大气顶部入射太阳辐射的季节周期驱动了这种不对称性。由于南方高纬度地区的日照偏离正弦曲线，夏季有一个较窄的强亮峰，冬季有较长的弱光期，因此夏季冰退缩迅速，冬季冰推进缓慢。这种简单的物理解释与以前的研究中提出的解释明显不同。
The mean seasonal cycle of Antarctic sea-ice extent is asymmetric, with the period of ice retreat being approximately two months shorter than the period of ice advance. This feature is largely consistent in observations from year to year and across different satellite products. The asymmetry is also broadly reproduced by comprehensive climate models across generations from CMIP3 to CMIP6, with limited impacts from internal variability. Using a range of idealized climate models of varying complexity, we show that the seasonal cycle in top-of-atmosphere incident solar radiation drives the asymmetry. Because insolation in southern high latitudes departs from a sinusoid by having a narrow peak of intense brightness in summer and a long period of low light in winter, there is rapid summer ice retreat and gradual winter ice advance. This simple physical explanation is markedly different from those proposed in previous studies.