【摘要】：土壤表層水汽傳輸阻抗是估算區(qū)域蒸散的關(guān)鍵參數(shù)之一,但其與土壤水熱參數(shù)的數(shù)量關(guān)系的研究在高寒系統(tǒng)中十分薄弱。利用渦度相關(guān)系統(tǒng)觀測(cè)的2014/2015年度高寒草甸非植被生長(zhǎng)季(11月-翌年4月)的土壤蒸發(fā)數(shù)據(jù),基于Penman-Monteith方程反推得出非生長(zhǎng)季土壤表層阻抗的晝(9:00-18:00)變化特征,并研究其與土壤5cm溫度和土壤5cm含水量的關(guān)系。結(jié)果表明,非生長(zhǎng)季土壤表層阻抗表現(xiàn)出單峰型日變化特征,其最大值一般出現(xiàn)在15:00前后。逐時(shí)土壤表層阻抗與土壤5cm溫度呈極顯著冪函數(shù)閾值關(guān)系(R2=0.38,P0.01,N=115),即土壤溫度為 4.25℃時(shí)土壤表層阻抗最大;與土壤5cm含水量呈極顯著指數(shù)負(fù)相關(guān)(R2=0.12,P0.01,N=115)。非生長(zhǎng)季逐日土壤表層阻抗的變化無(wú)明顯季節(jié)規(guī)律,與土壤5cm溫度(R2=0.69,P0.01,N=10)和土壤5cm含水量(R2=0.27,P0.01,N=10)均表現(xiàn)為極顯著指數(shù)負(fù)相關(guān)。相關(guān)分析表明,非生長(zhǎng)季土壤蒸發(fā)主要受太陽(yáng)總輻射(R20.50,P0.01)的控制。研究結(jié)果表明土壤溫度而非土壤含水量主導(dǎo)著高寒草甸非生長(zhǎng)季土壤表層阻抗的變化。
[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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