Relocation of major ions in snow along the Tundra-Taiga ecotone
Relocation of major ions in snow along the Tundra-Taiga ecotone
复制标题
苔原-针叶林交错带雪中主要离子的迁移
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
L. Lesack
中科院分区：
文献类型：
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作者：
J. Pomeroy;P. Marsh;L. Lesack
加拿大西北地区因努维克北部季节性积雪的化学成分是由生物物理景观分层的。在这个地区，冬季离子的沉积主要是通过风吹雪的再分配发生的，在森林边缘和山谷两侧的积累是开放苔原的8到12倍。除了SO42−外，大多数离子的负荷与雪的负荷并不完全成比例，在不同的景观单元中，离子浓度相对增加或减少有几种机制。浅雪温度梯度变质过程中的蒸发和光化学反应或气体清除过程中的吸收将NO3−−的浓度转化为50%。在森林地形和山谷底部，气溶胶的干沉降使Cl -、Na+、Mg2+、K+和Ca2+浓度增加了两倍以上，然而，气溶胶对吹雪颗粒的清除对风吹林带海盐的富集贡献了40%，对Ca2+的富集贡献了20%。结论是，如果不参考越冬物理和化学变质过程引起的变化，就不能可靠地推断北极雪化学的中心测量值。将物理/化学变化与易于识别的北极景观单元联系起来，为空间外推提供了一种简单而可靠的方法。
The chemistry of seasonal snowcovers north of Inuvik, Northwest Territories, Canada was stratified by biophysical landscape. In this region, deposition of ions in winter occurs largely through the redistribution of wind-blown snow with accumulations in forest-edges and valley sides 8 to 12 times that of the open tundra. While dominated by this snow redistribution, the loading of most ions, except for SO42−, does not scale exactly with that of snow, there being several mechanisms by which ion concentrations become relatively enriched or depleted in various landscape units. Vaporisation during temperature-gradient metamorphism in shallow-snow and uptake during either photochemical reactions or gaseous scavenging to well-exposed snow transformed concentrations of NO3−− by 50%. Dry deposition of aerosols to forested terrain and valley bottoms enriched Cl−, Na+, Mg2+, K+ and Ca2+ concentrations up to more than two-fold, however scavenging of aerosols to blowing snow particles contributed an additional 40% to the sea-salt enrichment and 20% to the Ca2+ enrichment in wind-blown treeline forests. It is concluded that central measurements of snow chemistry in the Arctic cannot be reliably extrapolated without reference to changes caused by over-winter physical and chemical metamorphic processes. Associating the physical/chemical changes with readily identifiable Arctic landscape units suggests a simple and robust method for spatial extrapolation.