Influences of changing sea ice and snow thicknesses on simulated Arctic winter heat fluxes
Influences of changing sea ice and snow thicknesses on simulated Arctic winter heat fluxes
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DOI：
10.5194/tc-16-1483-2022
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发表时间：
2022-04
期刊：
影响因子：
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通讯作者：
L. Landrum;M. Holland
中科院分区：
文献类型：
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作者：
L. Landrum;M. Holland
抽象的。在高纬度北极，冬季海冰和雪将相对温暖的海洋与寒冷的大气隔离开来。当气候变暖时，冬季北极表面热通量仍然由覆盖海洋的雪和海冰的隔热效应主导，直到海冰足够薄或海冰浓度降低到足以允许直接的海洋-大气热通量。社区地球系统模型版本 1 大型系综 (CESM1-LE) 模拟到 21 世纪中叶，冰雪覆盖的北冰洋冬季传导热通量增加约 7-11 W m−2，从而导致大气变暖加剧。这些增加的通量是由于海冰变薄和海冰上的积雪减少造成的。这里分析的模拟使用亚网格尺度的冰厚度分布。即使海冰浓度保持在 95% 以上，在冬季北极盆地，使用海冰厚度的网格单元平均值计算的表面热通量估计也会低估平均热通量 ~16%–35%，高估传导热通量变化高达 ~36%。这些结果凸显了即使在海冰浓度仍然很高并且雪和雪的分布显着影响北极冬季表面热收支的大规模计算的时期，在变暖的世界中冬季传导热通量也会增加。
Abstract. In the high-latitude Arctic, wintertime sea ice and snow insulate the relatively warmer ocean from the colder atmosphere. While the climate warms, wintertime Arctic surface heat fluxes remain dominated by the insulating effects of snow and sea ice covering the ocean until the sea ice thins enough or sea ice concentrations decrease enough to allow for direct ocean–atmosphere heat fluxes. The Community Earth System Model version 1 Large Ensemble (CESM1-LE) simulates increases in wintertime conductive heat fluxes in the ice-covered Arctic Ocean by ∼ 7–11 W m−2 by the mid-21st century, thereby driving an increased warming of the atmosphere. These increased fluxes are due to both thinning sea ice and decreasing snow on sea ice. The simulations analyzed here use a sub-grid-scale ice thickness distribution. Surface heat flux estimates calculated using grid-cell mean values of sea ice thicknesses underestimate mean heat fluxes by ∼16 %–35 % and overestimate changes in conductive heat fluxes by up to ∼36 % in the wintertime Arctic basin even when sea ice concentrations remain above 95 %. These results highlight how wintertime conductive heat fluxes will increase in a warming world even during times when sea ice concentrations remain high and that snow and the distribution of snow significantly impact large-scale calculations of wintertime surface heat budgets in the Arctic.