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地表土壤热通量是地表能量平衡的重要组成部分,对地表蒸散发的估算至关重要.利用土壤温湿度廓线观测资料基于热扩散方程计算地表土壤热通量,并通过冻土融化前后土壤液态水含量变化估算土壤含冰量,分析了土壤含冰量对土壤热通量的影响,旨在分析黑河流域典型下垫面(高山草地、农田和森林)地表土壤热通量的时空变化特征.研究结果表明:(1)黑河流域不同下垫面的地表土壤热通量有明显的日变化差异,日最大值时刻提前净辐射通量几分钟至几小时不等,这与土壤质地、湿度、热属性和植被覆盖度有关;(2)净辐射通量有显著的季节变化,一般夏季达最大值,冬季最小,地表土壤热通量也有明显的季节变化,但并不总是与净辐射通量变化保持一致,春季达最大值,夏季由于植被覆盖的原因反而降低;(3)地表土壤热通量占净辐射通量的比例因季节及下垫面不同而有差异,1月份月平均比值分别为:阿柔25.6%、盈科22.9%和关滩4.3%,7月份月平均比值分别为:阿柔2.3%、盈科1.6%和关滩0.3%;(4)冬季考虑了冰的热容量使得土壤热容量增加,土壤热存储增加,从而由热扩散方程计算的地表土壤热通量增加,使得能量平衡闭合率提高了4.3%.
The surface soil heat flux is an important part of surface energy balance and is very important for the estimation of surface evapotranspiration.Using the data of soil temperature and humidity profile to calculate the surface soil heat flux based on the thermal diffusion equation and through the frozen soil before and after thawing This paper analyzes the influence of soil ice content on soil heat flux and analyzes the spatio-temporal variation characteristics of surface soil heat flux of typical underlying surface (alpine meadow, farmland and forest) in the Heihe River basin The results show that: (1) There are obvious diurnal variations of surface soil heat fluxes on different underlying surfaces in the Heihe River basin, with daily maximum values of net radiation flux ranging from a few minutes to a few hours, which is related to soil texture, (2) There is a significant seasonal variation in net radiant flux, which is generally the maximum in summer and the smallest in winter. The surface soil heat flux also shows obvious seasonal changes, but it is not always consistent with the net radiation Flux changes remain the same, reaching the maximum in spring and decreasing in summer due to vegetation cover; (3) the ratio of surface soil heat flux to net radiant flux varies due to different seasons and underlying surface The monthly average ratios in January and January were 25.6%, 22.9% and 22.3% respectively. The monthly average ratios in July were: A soft 2.3%, PCCW 1.6% and Guantan 0.3%. (4) Winter Considering that the heat capacity of ice increases the heat capacity of soil and increases the heat storage of soil, the heat flux of surface soil calculated by heat diffusion equation increases, resulting in a 4.3% increase of energy balance closure rate.