Identification of the Factors Influencing the Baseflow in the Permafrost Region of the Northeastern Qinghai-Tibet Plateau
Identification of the Factors Influencing the Baseflow in the Permafrost Region of the Northeastern Qinghai-Tibet Plateau
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DOI：
10.3390/w9090666
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发表时间：
2017-09
期刊：
影响因子：
3.4
通讯作者：
Jia Qin;Yong-jian Ding;T. Han;Yuexiao Liu
中科院分区：
文献类型：
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作者：
Jia Qin;Yong-jian Ding;T. Han;Yuexiao Liu
基流是河流径流的重要组成部分。在永久冻土覆盖地区，基流变化的精确测量和分析具有挑战性。本文以疏勒河上游为研究区，研究其基流变化规律及其成因。采用基于ARNO基流公式的变入渗量（VIC）模型对基流进行了模拟。同位素基流分离结果和全年退潮期实测径流验证了模拟基流的有效性。研究发现，研究区近63.1%的河流径流来源于基流；基流全年变化相对平稳，比河流径流晚了几天。大约80%的基流产生于3500-4500 m的高寒地区，主要是低温和中温永久冻土带。基于多年冻土活动层的气候、径流、土地利用、土壤温湿度等资料，分析了多年冻土区基流变化的机理。降水和温度对多年冻土区的基流有显著的促进作用，但温度对基流的影响大于降水对基流的影响。研究区寒漠和高寒草原对基流的调节能力最大。受冻融过程的影响，春季基底流出现峰值，秋季基底流衰退放缓。这使得全年的基流和径流分布更加均匀。
Baseflow is an essential component of river runoff. Accurate measurements and analyses of baseflow change are challenging in permafrost-covered regions. In this paper, the upper reaches of the Shule River were selected as the study area, in which to study the baseflow change regulation and causes. The variable infiltration capacity (VIC) model, based on the ARNO baseflow formulation, was used to simulate the baseflow. Simulated baseflow was validated by the isotopic baseflow separation results and measured runoff in the recession periods throughout an entire year. It was found that approximately 63.1% of the river runoff was sourced by baseflow in the study region; the baseflow change was relatively smooth throughout the year, and it lagged a few days behind the river runoff. Approximately 80% of the total baseflow was generated in the 3500–4500 m alpine regions, with mainly low-temperature and mid-temperature permafrost. Based on the climate, runoff, land use, soil temperature and moisture data of the permafrost active layer, the mechanism of baseflow change in the permafrost zone was analysed. Precipitation and temperature positively enhanced the baseflow in the permafrost region throughout a year, but the baseflow was more influenced by the temperature than precipitation. In the study area, the cold desert and alpine grassland had the largest regulation capacity for baseflow. Affected by the permafrost freeze-thaw process, a baseflow peak occurred in the spring and the baseflow recession slowed in the autumn. This lead to a more uniform distribution of baseflow and runoff throughout the year.