Winter snow cover variability on East Antarctic sea ice
Winter snow cover variability on East Antarctic sea ice
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南极东部海冰冬季积雪变化
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
I. Allison
中科院分区：
文献类型：
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作者：
R. Massom;V. Lytle;A. Worby;I. Allison
美国地球物理联盟版权所有 1998。对冬季南极东部海冰上收集的第一个详细雪特征数据集的分析证实，在小尺度上，南极海冰上的雪在厚度和性质上都存在很大差异。与风暴通过相关的大气强迫的高振幅周期性变化是观察到的高度结构异质性的原因。研究人员在三周的时间里对雪特性的变化进行了研究，在此期间，随着气温骤降，在接近冰点的温度下形成的大部分冰雪覆盖物都变质为以多面晶体和深度灰白色为主的雪。即使在平坦的冰面上，局部积雪也会以新月形沙丘的形式显着增厚。尽管我们观察到局部尺度上的雪厚度和特性存在很大差异，但总体雪厚度分布和雪类型的复杂结构组合在不同地区是相似的。 Sturm 等人也做出了类似的观察。 [1998]在南极洲西部。尽管在各个浮冰之间再次发现了很高的变异性，但平均雪密度、颗粒尺寸和大雪盐度也存在明显的大规模相似性。快速深度雪白形成是一个普遍存在的过程，它极大地影响积雪的密度、质地、颗粒大小和有效导热性。观察到的不均匀性导致雪有效热导率的变化。根据观测到的雪类型的比例计算得出的平均体积有效导热系数为 0.164 W m-1 K-1，明显低于大规模海冰建模中通常使用的值，但与 Sturm 等人得出的值相似。 [1998]在别林斯高晋海和罗斯海几乎同时进行的实验中。不同雪坑的值从0.097到0.383 W m-1 K-1不等。研究结果支持 Sturm 等人的研究结果。 [1998] 周期性洪水和随后的冰雪形成也是普遍存在的过程，有效地减少了基础积雪过程在积雪中造成不均匀性的程度。
Copyright 1998 by the American Geophysical Union. Analysis of the first detailed data set of snow characteristics collected over East Antarctic sea ice in winter confirms that on small scales, snow on Antarctic sea ice is highly variable in both thickness and properties. High-amplitude cyclical variability in atmospheric forcing related to the passage of storms is responsible for the high degree of textural heterogeneity observed. Changes in snow properties were examined over a 3-week period, during which a largely icy snow cover, formed at near-freezing temperatures, metamorphosed to snow in which facetted crystals and depth hoar dominated, as the air temperature plummeted. Even on flat ice, significant localized thickening of snow occurs in the form of barchan dunes. Although we observed great variability in snow thickness and properties on local scales, overall snow thickness distribution and the complex textural assemblage of snow types are similar from region to region. Similar observations were made by Sturm et al. [1998] in West Antarctica. Large-scale similarities are also apparent in mean snow density, grain size, and bulk snow salinity, although high variability is again found across individual floes. Rapid depth hoar formation is a ubiquitous process that greatly affects the density, texture, grain size, and effective thermal conductivity of the snow cover. The observed heterogeneity results in varying snow effective thermal conductivities. The mean bulk effective thermal conductivity, computed from the proportion of observed snow types, is 0.164 W m-1 K-1, significantly lower than values typically used in large-scale sea ice modeling but similar to that derived by Sturm et al. [1998] in a near-simultaneous experiment in the Bellingshausen and Ross Seas. It varies from 0.097 to 0.383 W m-1 K-1 in different snow pits. The findings support those of Sturm et al. [1998] that periodic flooding and subsequent snow ice formation, which are also ubiquitous processes, effectively diminish the degree to which basal snow processes create inhomogeneities in the snow pack.