Snowmelt runoff and soil moisture dynamics on steep subalpine hillslopes
Snowmelt runoff and soil moisture dynamics on steep subalpine hillslopes
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亚高山陡坡融雪径流和土壤湿度动态
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
C. Moore
中科院分区：
文献类型：
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作者：
S. Kampf;J. Markus;J. Heath;C. Moore
融雪水在山区提供径流和生长季土壤水分，但融雪水的途径及其对水分模式的影响在很大程度上仍不清楚。本研究探讨了融雪径流过程中的径流过程对美国落基山国家公园两个陡峭的亚高山坡面土壤水分空间格局的影响。断面有东北向和向东两个方向，从高海拔的基岩露头向下延伸到谷底的溪流。在2008-2010年的积雪融化和夏季，沿这些样带调查了积雪深度和近地表土壤水分的空间格局。为了将这些模式与水流过程联系起来，在两个样带上连续测量土壤水分，并与附近溪流的排放时间进行比较。结果表明，在积雪融化过程中，这两个斜坡都产生了浅层侧向地下水流，穿过近地表土壤、冰川和基岩裂隙。在北东向断面上，这种浅层地下水流穿过坡中渗流带，在某些情况下产生饱和陆面流，而东向坡面没有渗流带或陆面流。在坡面尺度上，东向坡面的积雪融化时间早于东北面坡面，导致土壤平均水分状况较干燥，但在山坡内，除持续积雪的地区外，雪型与土壤水分状况关系不大。结果表明，在这一陡峭的亚高山地区，侧向流动和渗出过程是土壤水分空间格局的关键控制因素。版权所有©2014 John Wiley&Sons，Ltd.
Snowmelt water supplies streamflow and growing season soil moisture in mountain regions, yet pathways of snowmelt water and their effects on moisture patterns are still largely unknown. This study examined how flow processes during snowmelt runoff affected spatial patterns of soil moisture on two steep sub‐alpine hillslope transects in Rocky Mountain National Park, CO, USA. The transects have northeast‐facing and east‐facing aspects, and both extend from high‐elevation bedrock outcrops down to streams in valley bottoms. Spatial patterns of both snow depth and near‐surface soil moisture were surveyed along these transects in the snowmelt and summer seasons of 2008–2010. To link these patterns to flow processes, soil moisture was measured continuously on both transects and compared with the timing of discharge in nearby streams. Results indicate that both slopes generated shallow lateral subsurface flow during snowmelt through near‐surface soil, colluvium and bedrock fractures. On the northeast‐facing transect, this shallow subsurface flow emerged through mid‐slope seepage zones, in some cases producing saturation overland flow, whereas the east‐facing slope had no seepage zones or overland flow. At the hillslope scale, earlier snowmelt timing on the east‐facing slope led to drier average soil moisture conditions than on the northeast‐facing slope, but within hillslopes, snow patterns had little relation to soil moisture patterns except in areas with persistent snow drifts. Results suggest that lateral flow and exfiltration processes are key controls on soil moisture spatial patterns in this steep sub‐alpine location. Copyright © 2014 John Wiley & Sons, Ltd.