The influence of snow on sea ice as assessed from simulations of CESM2
The influence of snow on sea ice as assessed from simulations of CESM2
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DOI：
10.5194/tc-15-4981-2021
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发表时间：
2021-10-28
期刊：
影响因子：
5.2
通讯作者：
Webster, Melinda
中科院分区：
文献类型：
--
作者：
Holland, Marika M.;Clemens-Sewall, David;Webster, Melinda
我们在实验中评估了雪对海冰的影响，使用的是前工业化和2xCO2气候状态的共同体地球系统模型第2版。在前工业化气候中，我们发现，海冰上模拟积雪的增加导致海冰更厚，两个半球的气候更凉爽。海冰质量收支响应在两个半球之间存在根本差异。在北极，由于雪对传导热量和反照率的影响，雪量的增加导致海冰凝结增长和表层海冰融化的减少。这些因素在常年冰区占主导地位，但在季节性冰区影响较小。总体而言，质量预算的变化导致冰层厚度年度循环的幅度减小。在南极，随着雪的增加，冰的增长由于雪冰的形成而增加，并被更大的基冰融化所平衡，基冰融化主要发生在季节性冰区。在较暖的2×CO2气候中，北极海冰对雪深的敏感性较小，与前工业化气候相比有所降低。相比之下，在南极，在2xCO2气候下对海冰上积雪的敏感性与前工业化气候下的敏感性定性相似。这些结果强调了在耦合地球系统模型中准确描述海冰上积雪的重要性，因为它影响到影响海冰融化和生长的一些相互竞争的过程和反馈。
We assess the influence of snow on sea ice in experiments using the Community Earth System Model version 2 for a preindustrial and a 2xCO2 climate state. In the preindustrial climate, we find that increasing simulated snow accumulation on sea ice results in thicker sea ice and a cooler climate in both hemispheres. The sea ice mass budget response differs fundamentally between the two hemispheres. In the Arctic, increasing snow results in a decrease in both congelation sea ice growth and surface sea ice melt due to the snow's impact on conductive heat transfer and albedo, respectively. These factors dominate in regions of perennial ice but have a smaller influence in seasonal ice areas. Overall, the mass budget changes lead to a reduced amplitude in the annual cycle of ice thickness. In the Antarctic, with increasing snow, ice growth increases due to snow-ice formation and is balanced by larger basal ice melt, which primarily occurs in regions of seasonal ice. In a warmer 2xCO2 climate, the Arctic sea ice sensitivity to snow depth is small and reduced relative to that of the preindustrial climate. In contrast, in the Antarctic, the sensitivity to snow on sea ice in the 2xCO2 climate is qualitatively similar to the sensitivity in the preindustrial climate. These results underscore the importance of accurately representing snow accumulation on sea ice in coupled Earth system models due to its impact on a number of competing processes and feedbacks that affect the melt and growth of sea ice.