Long‐Term Soil Water Trends across a 1000‐m Elevation Gradient
Long‐Term Soil Water Trends across a 1000‐m Elevation Gradient
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1000 米海拔梯度范围内的长期土壤水趋势
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
D. Marks
中科院分区：
文献类型：
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作者：
M. Seyfried;D. Chandler;D. Marks
气候模型普遍认为，温度升高对蒸发需求的直接影响将导致土壤干燥，供水减少，干旱状况更加频繁。可用于评估气候变化可能导致的长期土壤水分趋势的数据很少。我们研究了在半干旱流域海拔1000米的四个地点收集的32年的土壤水数据。这些地点的气象数据先前已证实，在有记录的时期内，气温有显著上升的趋势，但没有显著的降水趋势。然而，有证据表明，随着海拔的升高，气候趋势可能会影响植物对气候变暖的反应。我们评估了土壤水分数据，以：（i）确定任何显着的时间趋势和（ii）比较土壤水分之间的网站，以评估空间趋势。在任何研究中心均未观察到显著的时间趋势。然而，强烈的空间趋势与海拔和季节。从数据中可以看出，对缺乏时间趋势有两种相互关联的解释。首先，这些半干旱系统是相对不敏感的温度升高的影响，因为蒸腾是有限的低叶面积，土壤含水量，太阳辐射，但每年4至5周。其次，在这些关键的几周内，土壤水分的年际变化程度很大，往往掩盖了土壤水分动态中可能存在的任何微妙的时间趋势。
There is a general consensus among climate models that the direct influence of increasing temperature on evaporative demand will result in drier soils, reduced water supply, and more frequent drought conditions. The data available to evaluate long‐term soil water trends that may result from climate change are sparse. We examine soil water data collected over a 32‐yr period at four sites covering a 1000‐m elevation gradient in a semiarid watershed. Meteorological data from these sites have previously confirmed a significant, increasing temperature trend with no significant precipitation trend during the period of record. There are, however, well‐documented climatic trends with elevation that may influence vegetative response to a warming climate. We evaluated the soil water data to: (i) determine any significant temporal trends and (ii) compare soil water among sites to evaluate spatial trends. No significant temporal trends were observed at any of the sites. There were, however, strong spatial trends with elevation and season. Two linked explanations for the lack of temporal trends emerge from the data. First, these semiarid systems are relatively insensitive to the effects of temperature increase because transpiration is limited by low leaf area, soil water content, and solar radiation for all but 4 to 5 wk per year. Second, the large degree of interannual variability of soil water during those critical weeks tends to obscure any subtle temporal trends in soil water dynamics that may be present.