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,P<0.01,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,P<0.01,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,P<0.01,N=10)和土壤5cm含水量(R2=0.27,P<0.01,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(R2>0.50,P<0.01)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。
Soil surface resistance to vapor transfer is crucial for accurately estimating regional evapotranspiration while the studies of how to quantify the relationship between the soil surface resistance and soil temperature and soil moisture are still lack in alpine region. The dataset of soil evaporation measured by the eddy covariance technique over an alpine meadow during non-growing season（November to following April） in 2014 and 2015 were analyzed. The daytime（9：00-18：00） soil surface resistance was deduced from the theoretical Penman-Monteith formula of soil evaporation and the correlation with the 5cm soil temperature and 5cm soil volumetric water content was studied. The results showed that diurnal pattern of soil surface resistance was unimodal with a peak occurring at about 15：00. The response of diurnal soil surface resistance to the 5cm soil temperature could be described as a power function with an optimum soil temperature of –4.25℃（R2=0.38, P0.01, N=115）. The diurnal soil surface resistance negatively correlated exponentially with the 5cm soil volumetric water content（R2=0.12, P0.01, N=115）. There was no evident seasonal variation in daily soil surface resistance. The relationship between daily soil surface resistance and the 5cm soil temperature（R2=0.69, P0.01, N=10） and the 5cm soil volumetric water content（R2=0.27, P0.01, N=10） could both be depicted by exponential equation. Correlation analysis revealed that diurnal and daily soil evaporation was mainly governed by incident solar radiation（R20.50, P0.01）. These finding suggested that the soil surface resistance during non-growing season in the alpine meadow was much more controlled by soil temperature, rather than soil moisture.
作者
张法伟
王军邦
林丽
李以康
郭小伟
曹广民
ZHANG Fa-wei WANG Jun-bang LIN Li LI Yi-kang GUO Xiao-wei CAO Guang-min(Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810001, China Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 Graduate University of Chinese Academy of Sciences, Beijing 100049)
出处
《中国农业气象》
CSCD
北大核心
2017年第2期96-103,共8页
Chinese Journal of Agrometeorology
基金
国家自然科学基金(31270520
31270576)
中国科学院科技服务网络计划(KFJ-EW-STS-125)
