Climate Elasticity of Low Flows in the Maritime Western U.S. Mountains
Climate Elasticity of Low Flows in the Maritime Western U.S. Mountains
复制标题
美国西部沿海山区低流量的气候弹性
DOI：
10.1029/2018wr022816
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发表时间：
2018
影响因子：
5.4
通讯作者：
D. Lettenmaier
中科院分区：
文献类型：
--
作者：
M. Cooper;J. Schaperow;S. Cooley;S. Alam;L. Smith;D. Lettenmaier
夏季径流是一个重要的水资源，在干燥的夏季在美国西部，但夏季最小径流（低流量）的敏感性，以前期冬季降水相比，夏季蒸发需求尚未量化的区域。我们估计低流量的气候弹性（低流量的百分比变化除以气候强迫变量的百分比变化）相对于年最大雪水当量（ESWE），冬季降水量（EPPT）和夏季潜在蒸散量（EPET）为110个未管理的河源集水区在美国西部山区。我们发现|EPET|大于|EPPT|和|ESWE|在每一个集水区研究和4-5倍以上，平均。E的空间变化主要有三种模式。第一、|EPPT|, |ESWE|得双曲正弦值.| EPET|是最大的和最易变的半干旱集水区和减少非线性增加值的湿度指数（年降水量与年蒸发量的比率）。第二、|EPPT|和|EPET|在以雪为主的集水区中的流量比以雨为主的集水区低，这表明积雪减少了低流量对气候变化的比例响应。第三、|EPPT|, |ESWE|得双曲正弦值.| EPET|在缓慢排水集水区中，基流退蓄系数低于快速排水集水区，基流退蓄系数用于表示集水区蓄水转化为径流的速率。我们的研究结果首次比较了夏季低流量弹性与PPT和PET及其在美国西部沿海山区的空间变化。
Summer streamflow is an important water resource during the dry summers in the western United States, but the sensitivity of summer minimum streamflow (low flow) to antecedent winter precipitation as compared with summer evaporative demand has not been quantified for the region. We estimate climatic elasticity of low flow (percent change in low flow divided by percent change in climatic forcing variable) with respect to annual maximum snow water equivalent (ESWE), winter precipitation (EPPT), and summer potential evapotranspiration (EPET) for 110 unmanaged headwater catchments in the maritime western U.S. mountains. We find that |EPET| is larger than |EPPT| and |ESWE| in every catchment studied and is 4–5 times larger than both, on average. Spatial variations in E are dominated by three patterns. First, |EPPT|, |ESWE|, and |EPET| are largest and most variable among semiarid catchments and decrease nonlinearly with increasing values of the humidity index (the ratio of annual precipitation to annual evaporative demand). Second, |EPPT| and |EPET| are lower in snow‐dominated catchments than in rain‐dominated catchments, suggesting that snow cover reduces the proportional response of low flows to climatic variability. Third, |EPPT|, |ESWE|, and |EPET| are lower in slow‐draining catchments than in fast‐draining catchments, for which baseflow recession storage coefficients are used to represent the rate at which catchment water storage is translated into streamflow. Our results provide the first comparison of summer low‐flow elasticity to PPT versus PET and its spatial variation in the maritime western U.S. mountains.
关键带的排水：夏季旱季润湿河道持续性和空间范围的岩性控制
影响因子：
5.4
作者：
Lovill, S. M.;Hahm, W. J.;Dietrich, W. E.
通讯作者：
Dietrich, W. E.