Impacts of Oceanic and Atmospheric Heat Transports on Sea Ice Extent
Impacts of Oceanic and Atmospheric Heat Transports on Sea Ice Extent
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DOI：
10.1175/jcli-d-19-0761.1
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发表时间：
2020-08
影响因子：
4.9
通讯作者：
Jake Aylmer;D. Ferreira;D. Feltham
中科院分区：
文献类型：
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作者：
Jake Aylmer;D. Ferreira;D. Feltham
海洋热传输（OHT）的气候模式偏差已被认为是海冰范围预测不确定性的主要因素。为了更好地理解OHT对海冰范围的影响，并将其与大气热输送（AHT）进行比较，建立了一个理想化的纬向平均能量平衡模式（EBM）。这是区别于以往的EBM工作耦合扩散混合层OHT和规定的OHT的贡献，与大气EBM和降低复杂性的海冰模式。冰缘纬度与各热输送分量的辐合大致呈线性关系，其敏感性取决于冰盖是常年性还是季节性的。在这两种制度中，Bjerknes补偿（BC）发生，使得AHT的响应部分抵消了OHT变化的影响。因此，冰缘退缩对OHT增加的有效敏感性仅为实际敏感性的2/3（即，消除BC效应）。在常年制度，冰缘OHT的敏感性约两倍，AHT，而在季节性制度，他们是相似的。灵敏度的比例，领先的顺序，确定在常年制度的大气长波反馈参数。在这里，没有参数范围内的冰边缘是更敏感的AHT比OHT。
Climate-model biases in ocean heat transport (OHT) have been proposed as a major contributor to uncertainties in projections of sea ice extent. To better understand the impact of OHT on sea ice extent and compare it to that of atmospheric heat transport (AHT), an idealized, zonally averaged energy balance model (EBM) is developed. This is distinguished from previous EBM work by coupling a diffusive mixed layer OHT and a prescribed OHT contribution, with an atmospheric EBM and a reduced-complexity sea ice model. The ice-edge latitude is roughly linearly related to the convergence of each heat transport component, with different sensitivities depending on whether the ice cover is perennial or seasonal. In both regimes, Bjerknes compensation (BC) occurs such that the response of AHT partially offsets the impact of changing OHT. As a result, the effective sensitivity of ice-edge retreat to increasing OHT is only ~2/3 of the actual sensitivity (i.e., eliminating the BC effect). In the perennial regime, the sensitivity of the ice edge to OHT is about twice that to AHT, while in the seasonal regime they are similar. The ratio of sensitivities is, to leading order, determined by atmospheric longwave feedback parameters in the perennial regime. Here, there is no parameter range in which the ice edge is more sensitive to AHT than OHT.