| 唐古拉地区活动层水热状况及地气系统能水平衡分析 |
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| 引用本文： | 郭林茂,常娟,周剑,徐洪亮.唐古拉地区活动层水热状况及地气系统能水平衡分析[J].高原气象,2020(2):254-265. |
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| 作者姓名： | 郭林茂 常娟 周剑 徐洪亮 |
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| 作者单位： | 兰州大学资源环境学院;中国科学院西北生态环境资源研究院冻土工程国家重点实验室 |
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| 基金项目： | 国家自然科学基金项目(41671015,91547203)。 |
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| 摘 要： | 活动层水热状况与地-气系统间能水交换直接影响着寒区生态环境、水文过程以及多年冻土的稳定性。利用唐古拉站2007年实测资料和SHAW模型,对研究点活动层土壤剖面温湿度进行了模拟。土壤温度方面,模型的纳什效率系数NSE≥0.93;水分方面,纳什效率系数的平均值为0.69,说明SHAW模型可用于多年冻土区活动层内水热动态变化的模拟研究。基于模型的输出结果,对唐古拉站活动层土壤冻融过程中的水分动态、地表能量收支的变化特征进行了分析讨论。结果表明:(1)活动层冻融过程中,土壤水分的冻结和融化响应时间随土壤深度的增加而逐渐滞后,水分迁移通量随土壤深度的增加逐渐减小;(2)地表能量平衡收支在季风活动引起的降水与活动层的冻融循环共同影响下,表现出明显的季节性变化特征。同时,通过改变SHAW模型植被输入参数中的叶面积指数,分析了植被覆盖变化对多年冻土区土壤蒸散发的影响。结果表明:植被蒸腾量、土壤蒸发量与总的蒸散发量与植被的叶面积指数呈正相关关系,而浅层土壤含水率(20 cm)则表现为负相关,当叶面积指数在-100%(裸土)~100%变化时,总蒸散发量的变化幅度为-5%~13%。
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| 关 键 词： | 青藏高原 SHAW模型 活动层 能量平衡 水分动态 植被 |
Analysis of Thermal-Moisture Conditions of Active Layer and Energy-Water Balance of Land-Atmosphere System in Tanggula Area |
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| GUO Linmao,CHANG Juan,ZHOU Jian,XU Hongliang.Analysis of Thermal-Moisture Conditions of Active Layer and Energy-Water Balance of Land-Atmosphere System in Tanggula Area[J].Plateau Meteorology,2020(2):254-265. |
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| Authors: | GUO Linmao CHANG Juan ZHOU Jian XU Hongliang |
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| Institution: | (College of Earth and Environmental Sciences,Lanzhou University,Lanzhou 730000,Gansu,China;State Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,Gansu,China) |
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| Abstract: | The thermal-moisture conditions of the active layer and the energy-water exchange between land-atmosphere system directly affect the ecological environment,hydrological process and the stability of the permafrost in cold regions.The soil temperature and moisture contents within the active layer at Tanggula station in 2007 were simulated by SHAW model.In terms of soil temperature,the Nash efficiency coefficient(NSE)is greater than 0.93,and the average value of the NSE between simulated and measured soil moisture is 0.69,indicating that the SHAW model can perfectly simulate the thermal-moisture dynamics within the active layer of permafrost regions.Based on the output of SHAW model,the variation characteristics of water dynamics and surface energy budget during the process of soil freezing and thawing in the active layer of Tanggula station were analyzed and discussed.Results showed that:(1)During the freezing and thawing process of the active layer,the soil moisture freezing and thawing response time gradually lagged with the increase of soil depth,and the water migration flux decreased with soil depth,and during the freezing period,the soil moisture has a characteristic of two-way convergence to the surface and deep layers;(2)Under the combined influence of the monsoon activities and the freezing-thawing process in the active layer,the surface energy budget showed obvious seasonal variation characteristics.The effect of vegetation on soil evapotranspiration in permafrost regions was investigated by changing the leaf area index in the vegetation input parameters of the SHAW model.Results showed that there was a positive correlation between vegetation transpiration,soil evaporation and total evapotranspiration and leaf area index of vegetation,while shallow soil moisture content(at 20 cm)showed a negative correlation when leaf area index varied from-100%(bare soil)to 100%,the total evapotranspiration varied from-5%to 13%. |
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| Keywords: | Qinghai-Tibetan Plateau SHAW model active layer energy balance moisture dynamics vegetation |
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