高寒草甸非生长季土壤表层水汽传输阻抗的变化特征和水热驱动

发布时间：2018-10-17 19:15

【摘要】：土壤表层水汽传输阻抗是估算区域蒸散的关键参数之一,但其与土壤水热参数的数量关系的研究在高寒系统中十分薄弱。利用涡度相关系统观测的2014/2015年度高寒草甸非植被生长季(11月-翌年4月)的土壤蒸发数据,基于Penman-Monteith方程反推得出非生长季土壤表层阻抗的昼(9:00-18:00)变化特征,并研究其与土壤5cm温度和土壤5cm含水量的关系。结果表明,非生长季土壤表层阻抗表现出单峰型日变化特征,其最大值一般出现在15:00前后。逐时土壤表层阻抗与土壤5cm温度呈极显著幂函数阈值关系(R2=0.38,P0.01,N=115),即土壤温度为 4.25℃时土壤表层阻抗最大;与土壤5cm含水量呈极显著指数负相关(R2=0.12,P0.01,N=115)。非生长季逐日土壤表层阻抗的变化无明显季节规律,与土壤5cm温度(R2=0.69,P0.01,N=10)和土壤5cm含水量(R2=0.27,P0.01,N=10)均表现为极显著指数负相关。相关分析表明,非生长季土壤蒸发主要受太阳总辐射(R20.50,P0.01)的控制。研究结果表明土壤温度而非土壤含水量主导着高寒草甸非生长季土壤表层阻抗的变化。
[Abstract]:Surface water vapor transport impedance is one of the key parameters for estimating regional evapotranspiration, but the quantitative relationship between soil moisture and thermal parameters is very weak in the alpine system. Based on the soil evaporation data of non-vegetation growing season (November-April of the following year) observed in the Alpine Meadow in 2014 / 2015, the variation characteristics of soil surface impedance in non-growing season (9: 00-18: 00) were derived from the Penman-Monteith equation. The relationship between soil 5cm temperature and soil 5cm water content was studied. The results showed that the soil surface impedance showed a single peak diurnal variation in non-growing season, and its maximum value appeared around 15:00. There was a significant power function threshold relationship between soil surface impedance and soil 5cm temperature (R _ 2N _ (0.38) P _ (0.01) N _ (115), that is, soil surface impedance was the largest at 4.25 鈩，

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