The growth of sublimation crystals and surface hoar on the Antarctic plateau
The growth of sublimation crystals and surface hoar on the Antarctic plateau
复制标题
南极高原升华晶体的生长和地表白白
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
E. Brun
中科院分区：
文献类型：
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作者：
J. Gallet;F. Dominé;J. Savarino;M. Dumont;E. Brun
在南极高原，降水量很低，地面物质收支主要取决于雪面与大气表面之间的水汽交换。在冰穹C（南纬75度，东经123度），我们经常观察到在晴朗的天气下雪表面上晶体的生长。在这里，我们提出的时间变化的比表面积（SSA）和密度的这些晶体。使用详细的雪模型Crocus，我们得出结论，这些晶体的形成很可能是由于夜间形成的表面灰白色晶体和白天形成的升华晶体。这些晶体的形成过程类似于年轻海冰上霜花的形成过程。这些晶体的形成影响了南极高原的能量、质量和能量收支。特别是近地层SSA的变化，在中午可在雪面产生高达10W m2的瞬时强迫，导致雪面温度下降0.45K。这一结果证实，雪SSA是一个重要的变量，考虑在能量预算和气候的积雪覆盖的表面。
On the Antarctic plateau, precipitation quantities are so low that the surface mass budget is for an impor- tant part determined by exchanges of water vapor between the snow surface and the atmosphere surface. At Dome C (75 S, 123 E), we have frequently observed the growth of crystals on the snow surface under calm sunny weather. Here we present the time variations of specific surface area (SSA) and density of these crystals. Using the detailed snow model Crocus, we conclude that the formation of these crystals was very likely due to the nighttime formation of surface hoar crystals and to the daytime formation of sublimation crys- tals. These latter crystals form by processes similar to those involved in the formation of frost flowers on young sea ice. The formation of these crystals impacts the albedo, mass and energy budget of the Antarctic plateau. In particular, the SSA variations of the surface layer can induce an instantaneous forcing at the snow surface up to 10 W m 2 at noon, re- sulting in a surface temperature drop of 0.45 K. This result confirms that snow SSA is a crucial variable to consider in the energy budget and climate of snow-covered surfaces.