Temporal variation of soil moisture over the Wuding River basin assessed with an eco-hydrological model, in-situ observations and remote sensing
Temporal variation of soil moisture over the Wuding River basin assessed with an eco-hydrological model, in-situ observations and remote sensing
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DOI：
10.5194/hess-13-1375-2009
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发表时间：
2008-12
影响因子：
6.3
通讯作者：
Suxia Liu;X. Mo;W. Zhao;V. Naeimi;D. Dai;C. Shu;L. Mao
中科院分区：
文献类型：
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作者：
Suxia Liu;X. Mo;W. Zhao;V. Naeimi;D. Dai;C. Shu;L. Mao
抽象的。利用基于生态水文过程的模型、植被界面过程模型，利用1956~2004年模拟的土壤水分资料，探讨了黄土高原无定河流域土壤水分的变化规律和趋势。利用现场SM观测数据和维也纳理工大学遥感SM数据集验证了模型的有效性。在VIP模型中，利用降水、气温和径流观测等气候-生态-水文(CEH)变量，以及模拟的蒸散量(ET)、叶面积指数(LAI)和植被产量来分析土壤水分的演变机制。结果表明，该模式能较好地捕捉SM的季节变化。CEH变量较好地解释了SM在日、月和年尺度上的季节变化、多年变化、标准差和变异系数(CV)。与其他CEH变量相比，SM的年际变率最小。趋势分析表明，SM在α=0.0 1显著水平上呈下降趋势，证实了北方干燥现象。降水的减少趋势(α=0.1)和气温的升高趋势(α=0.0 1)可以很好地解释这一趋势。径流的减少趋势具有较高的显著水平(α=0.001)。由于SM的减少趋势，土壤蒸发量(ES)也在减少(α=0.0 5)。净辐射(Rn)、蒸散(ET)、蒸腾(EC)、冠层截距(Ei)变化趋势不明显。净第一性生产力显著水平低于α=0.1时，总第一性生产力在α=0.01时呈上升趋势。
Abstract. The change pattern and trend of soil moisture (SM) in the Wuding River basin, Loess Plateau, China is explored based on the simulated long-term SM data from 1956 to 2004 using an eco-hydrological process-based model, Vegetation Interface Processes model, VIP. In-situ SM observations together with a remotely sensed SM dataset retrieved by the Vienna University of Technology are used to validate the model. In the VIP model, climate-eco-hydrological (CEH) variables such as precipitation, air temperature and runoff observations and also simulated evapotranspiration (ET), leaf area index (LAI), and vegetation production are used to analyze the soil moisture evolution mechanism. The results show that the model is able to capture seasonal SM variations. The seasonal pattern, multi-year variation, standard deviation and coefficient of variation (CV) of SM at the daily, monthly and annual scale are well explained by CEH variables. The annual and inter-annual variability of SM is the lowest compared with that of other CEH variables. The trend analysis shows that SM is in decreasing tendency at α=0.01 level of significance, confirming the Northern Drying phenomenon. This trend can be well explained by the decreasing tendency of precipitation (α=0.1) and increasing tendency of temperature (α=0.01). The decreasing tendency of runoff has higher significance level (α=0.001). Because of SM's decreasing tendency, soil evaporation (ES) is also decreasing (α=0.05). The tendency of net radiation (Rn), evapotranspiration (ET), transpiration (EC), canopy intercept (EI) is not obvious. Net primary productivity (NPP), of which the significance level is lower than α=0.1, and gross primary productivity (GPP) at α=0.01 are in increasing tendency.