海北高寒草甸地区能量平衡特征

以微气候观测为基础,研究晴天状况下海北高寒草甸地区净辐射通量、土壤热通量、感热通量和潜热通量变化等特征。结果表明:(1)该地区总辐射的水平较高,2000年4～10月达4227.049W·m^-2,地表反射率在4～10月平均为0.23,在植物生长盛期的5～9月为0.22。(2)正向净辐射约占天空总辐射的56%左右;一日间土壤热通量、感热通量和潜热通量所占净辐射通量的比例在不同季节变化差异较大,在所选择的6月到9月的4个晴天个例状况平均分别所占的比例为28.6%、68.0%和3.4%,表现出潜热通量在净辐射能量的分配中所占比例较大,感热通量次之,土壤热通量则很小。(3)各通量所通过零点的时间基本一致,一般在日出后的7:00和日落前的19:00。

Energy-Balance Features of the Alpine Meadows on the Haibei Area(Northern Shores of the Qinghai Lake)

Based on a microclimate observation,a study,on fine days,of the net radiation flux,soil heat flux, sensible heat flux,and latent heat flux on the alpine meadows of Haibei Area was conducted.The result shows:1.Being an area of high sunradiation,Haibei boasted a radiation level of 4227.049 W·M^-2 from April until October 2000,an average monthly rate of surface reflection of 0.23,and a rate of surface reflection of 0.22 during the plant flourishing May to September.2.The net direct solar radiation of the alpine meadow area accounted for 56% of the total radiation.The dailty ratio of soil heat flux,sensible heat flux,and latent heat flux changed radically with the alternation of seasons.In the four sunny days chosen from June through September 2000,the ratio of the above-mentioned averaged 3.4%,28.6%,and 68.0% respectively in one day.The latent heat flux occupied a bigger proportion of the net radiation flux,followed by sensible heat flux,and then the soil heat flux.3.The various fluxes dropped to zero at approximately the same time,generally at 7:00 after sunrise and 19:00 before sunset.