Holland Marika M, Landrum Laura, Raphael Marilyn, Stammerjohn Sharon
National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO, 80307-3000, USA.
Department of Geography, University of California, Los Angeles, 1255 Bunche Hall, Los Angeles, CA, 90095-1524, USA.
Nat Commun. 2017 Sep 28;8(1):731. doi: 10.1038/s41467-017-00820-0.
Autumn sea ice trends in the western Ross Sea dominate increases in Antarctic sea ice and are outside the range simulated by climate models. Here we use a number of independent data sets to show that variability in western Ross Sea autumn ice conditions is largely driven by springtime zonal winds in the high latitude South Pacific, with a lead-time of 5 months. Enhanced zonal winds dynamically thin the ice, allowing an earlier melt out, enhanced solar absorption, and reduced ice cover the next autumn. This seasonal lag relationship has implications for sea ice prediction. Given a weakening trend in springtime zonal winds, this lagged relationship can also explain an important fraction of the observed sea ice increase. An analysis of climate models indicates that they simulate weaker relationships and wind trends than observed. This contributes to weak western Ross Sea ice trends in climate model simulations.Antarctic sea ice extent continues to increase, with autumn sea ice advances in the western Ross Sea particularly anomalous. Here, based on analysis of independent datasets, the authors show that springtime zonal winds in the high latitude South Pacific drive western Ross Sea autumn sea ice conditions.
罗斯海西部的秋季海冰变化趋势主导了南极海冰的增加，且超出了气候模型的模拟范围。在此，我们使用多个独立数据集表明，罗斯海西部秋季冰情的变化在很大程度上是由南太平洋高纬度地区春季纬向风驱动的，超前时间为5个月。增强的纬向风会使海冰动态变薄，导致更早融化，增强太阳吸收，并使次年秋季海冰覆盖面积减少。这种季节性滞后关系对海冰预测具有重要意义。鉴于春季纬向风呈减弱趋势，这种滞后关系也可以解释观测到的海冰增加的很大一部分原因。对气候模型的分析表明，它们模拟的关系和风向趋势比观测到的要弱。这导致了气候模型模拟中罗斯海西部海冰趋势较弱。南极海冰范围持续增加，罗斯海西部秋季海冰的推进尤为异常。在此，基于对独立数据集的分析，作者表明南太平洋高纬度地区的春季纬向风驱动了罗斯海西部秋季海冰状况。
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