Soil moisture variability across climate zones
Soil moisture variability across climate zones
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DOI：
10.1029/2007gl031382
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发表时间：
2007-10
影响因子：
5.2
通讯作者：
J. Lawrence;G. Hornberger
中科院分区：
文献类型：
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作者：
J. Lawrence;G. Hornberger
土壤湿度的变异性受大气条件的时间变异性和地表条件的空间变异性控制。在半干旱区，随着土壤平均含水量的增加，变化幅度增大；在湿润区，随着土壤平均含水量的增加，变化幅度减小；在温带地区，变化幅度在中等含水量时达到峰值。我们在美国弗吉尼亚州谢南多厄国家公园（Shenandoah National Park）的大草地（Big Meadows）高地湿地收集了土壤水分数据，我们观察到中等水分含量的峰值变化，与温带气候区的其他地点一致。一个改良的土壤水分动力学模型用于研究土壤水分模式如何随时间演变，地形、土壤和植被如何影响这些模式，以及如何解释跨气候带观测到的趋势。观测到的趋势与土壤水分分布的理论界限有关，即萎蔫点和孔隙率。
Variability in soil moisture is controlled by temporal variability in atmospheric conditions and spatial variability in land‐surface conditions. Observations of soil moisture have revealed a variety of patterns – generally, in semiarid regions variance increased as mean soil moisture content increased, in humid regions variance decreased as mean soil moisture content increased, and in temperate regions variance peaked at intermediate moisture contents. We collected soil moisture data at Big Meadows, an upland wetland in Shenandoah National Park, Virginia, and we observed peak variance at intermediate moisture contents, consistent with other sites in temperate climate zones. A modified soil moisture dynamics model was used to examine how soil moisture patterns evolve through time, how topography, soil, and vegetation affect these patterns, and how the trends observed across climate zones can be explained. The trends observed relate to theoretical bounds on soil moisture distributions, i.e., the wilting point and the porosity.