The role of thermal convection in heat and mass transport in the subarctic snow cover
The role of thermal convection in heat and mass transport in the subarctic snow cover
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热对流在亚北极积雪热量和质量传输中的作用
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
M. Sturm
中科院分区：
文献类型：
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作者：
M. Sturm
翻译后摘要：本研究探讨了在移动的热量和水蒸气在雪中的空气对流的作用。为了检测对流，在费尔班克斯积雪的三维温度场每小时测量3个冬季（1984- 1987年）。每月对雪的密度、压实度和粒度进行测量，以确定水蒸气通量和结构变化。雪变质成深度白霜，产生五层的序列，包括一个水平c轴的基底层。上覆层中的C轴垂直或随机取向。随着白霜深度的增加，它的透气性比以前测量的任何雪都高出几倍，而每单位体积的雪粒数量减少了一个数量级，因为一些精选的雪粒生长，而其他的则升华了。同时，由于质量通量梯度，从雪的底部到顶部有一个净质量转移。对流在1984-85年冬季零星发生，在1985-86年和1986-87年冬季持续发生。证据是：（1）雪中水平面上不同位置同时升温和降温;（2）水平温度梯度高达16 ℃/m。对流是随时间变化的，强风或气温的快速变化等扰动会触发水平温度梯度最强的时期，这表明这些时期也是气流最快的时期。在冬季，暖区和冷区在雪中发展，并在空间上保持相对固定。这些区域可能是与雪/土壤界面温度的空间变化有关的扩散羽状对流模式的结果。
Abstract : This study investigated the role of air convection in moving heat and water vapor in snow. To detect convection, the three-dimensional temperature field in the Fairbanks snow cover was measured hourly during 3 winters (1984- 1987). Measurements of snow density, compaction, and grain size were made monthly to determine water vapor flux and textural changes. The snow metamorphosed into depth hoar, producing a sequence of five layers, including a basal layer with horizontal c-axes. C-axes in the overlying layers were vertical or randomly oriented. As the depth hoar developed, its air permeability increased to several times higher than previously measured for any snow, while the number of snow grains per unit volume decreased by an order of magnitude as a few select grains grew while others sublimated away. Simultaneously, there was a net transfer of mass from the base to the top of the snow due to mass flux gradients. Convection occurred sporadically in the winter of 1984-85 and continuously in the winters of 1985-86 and 1986-87. The evidence was (1) simultaneous warming and cooling at different locations in a horizontal plane in the snow; and (2) horizontal temperature gradients of up to 16C/m. The convection was time-dependent, with perturbations such as high wind or rapid changes in air temperature triggering periods when horizontal temperature gradients were strongest, suggesting these were also periods when the air flow was fastest. During the winter, warm and cold zones developed in the snow and remained relatively fixed in space. The zones were probably the result of a diffuse plume-like convection pattern linked to spatial variations in the temperature of the snow/soil interface.
东海大学出版社
DOI：
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发表时间：
2006
期刊：
影响因子：
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作者：
Nishida;Mutsumi (ed.)
通讯作者：
Mutsumi (ed.)