敦煌戈壁冬夏季地表辐射与能量平衡特征对比研究

Contrast of Ground Surface Radiation-Energy Balance in Summer and Winter on Dunhuang Gobi

利用敦煌戈壁夏(2006年7月)、冬(2007年1月1—10日)季观测得到的微气象资料,比较了夏、冬季敦煌戈壁的地表辐射平衡、能量平衡特征。分析了地表反照率(Albedo)与土壤特性的关系,发现地表反照率和表层土壤温度日变化呈反相关;冬季地表反照率和土壤湿度的线性相关差,夏季地表反照率和土壤湿度的线性相关性好;地表反照率和土壤热通量呈反相关,并且冬季二者的拟合性好于夏季。分析了降水前后各能量通量的变化,发现阵雨时感热H是变小的,降雨过后H和净辐射Rn有明显的增大,土壤热通量Gn在降雨过后也有增大,潜热LE变化微弱,对阵性降水强迫后的非平衡态的张弛时间大约为3 d。

The observed microclimate data in 2006 and 2007 on Dunhuang Gobi area were used to study the ground surface albedo-energy balance in summer（July） and in winter（January）. It was disclosed that the soil surface albedo has close relation with soil characteristics： negative relation with diurnal soil surface temperature variation in winter and summer; good linear relation with soil humidity in summer and not obvious relation in winter; positive relation with soil heat flux, especially obvious in winter. Analysis of heat flux change preor after rainfall showed that the heat flux decreased in a shower, immediately increased after the shower; the net radiation and soil heat flux also increased after a shower, but the latent heat flux changed less. The lasting period of the uneven state after shower was about three days.