The influence of diurnal snowmelt and transpiration on hillslope throughflow and stream response
The influence of diurnal snowmelt and transpiration on hillslope throughflow and stream response
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DOI：
10.5194/hess-22-4295-2018
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发表时间：
2018-08
影响因子：
6.3
通讯作者：
Brett Woelber;M. Maneta;J. Harper;K. Jencso;W. Gardner;A. Wilcox;I. López-Moreno
中科院分区：
文献类型：
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作者：
Brett Woelber;M. Maneta;J. Harper;K. Jencso;W. Gardner;A. Wilcox;I. López-Moreno
抽象的。春季，亚高山森林集水区的日径流量和地下水动态在很大程度上受昼夜能量循环的水文过程控制。昼夜融雪和蒸腾事件联合收割机，以引起传播到流的土壤水存储的压力变化。在源头集水区，这些压力变化可以占系统总压力的很大一部分，并控制着每日尺度的水流流入脉冲的大小、持续时间和时间，特别是在低流量系统中。积雪顶部辐射平衡的变化可以改变山坡-溪流系统的昼夜水文动力学，具有潜在的生态和管理后果。我们提出了一个详细的每小时的大气，山坡，并在一个融化的季节，从美国蒙大拿州西部的半高山源头集水区流量测量数据集。我们使用这个数据集来研究融雪主导的水文过程之间的时间，模式和联系，并评估积雪，蒸腾作用和山坡在调解水从积雪顶部到当地河流系统的日常运动中的作用。我们发现，积雪冷含量积累在夜间，这必须克服每天早上之前，融雪恢复，延迟水补给输入长达3小时早在融化季节。多日的风暴（冷锋）使这些延误进一步加剧，导致土壤和河流储存量严重减少。我们还发现，昼夜融雪和蒸腾信号都存在于昼夜土壤和流存储波动，虽然这些过程的个人贡献是很难辨别的。我们的分析表明，水文响应的雪山坡流系统是高度敏感的大气驱动程序在小时尺度和大气能量输入或其他压力的变化迅速传输和改变强度，持续时间和时间的融雪脉冲和土壤水分提取植被，最终驱动土壤和溪流水压力的变化。
Abstract. During spring, daily stream flow and groundwater dynamics in forested subalpine catchments are to a large extent controlled by hydrological processes that respond to the day–night energy cycle. Diurnal snowmelt and transpiration events combine to induce pressure variations in the soil water storage that are propagated to the stream. In headwater catchments these pressure variations can account for a significant amount of the total pressure in the system and control the magnitude, duration, and timing of stream inflow pulses at daily scales, especially in low-flow systems. Changes in the radiative balance at the top of the snowpack can alter the diurnal hydrologic dynamics of the hillslope–stream system, with potential ecological and management consequences. We present a detailed hourly dataset of atmospheric, hillslope, and streamflow measurements collected during one melt season from a semi-alpine headwater catchment in western Montana, US. We use this dataset to investigate the timing, pattern, and linkages among snowmelt-dominated hydrologic processes and assess the role of the snowpack, transpiration, and hillslopes in mediating daily movements of water from the top of the snowpack to local stream systems. We found that the amount of snowpack cold content accumulated during the night, which must be overcome every morning before snowmelt resumes, delayed water recharge inputs by up to 3 h early in the melt season. These delays were further exacerbated by multi-day storms (cold fronts), which resulted in significant depletions in the soil and stream storages. We also found that both diurnal snowmelt and transpiration signals are present in the diurnal soil and stream storage fluctuations, although the individual contributions of these processes are difficult to discern. Our analysis showed that the hydrologic response of the snow–hillslope–stream system is highly sensitive to atmospheric drivers at hourly scales and that variations in atmospheric energy inputs or other stresses are quickly transmitted and alter the intensity, duration, and timing of snowmelt pulses and soil water extractions by vegetation, which ultimately drive variations in soil and stream water pressures.