塔克拉玛干沙漠腹地地表辐射与能量平衡

利用2013年塔克拉玛干沙漠塔中流动沙面地表辐射、土壤热通量、土壤温湿度和湍流通量观测资料，分析了沙漠腹地地表辐射和能量收支特征及闭合状况。结果表明：除潜热通量外，其余地表辐射各分量和能量平衡分量的月平均日变化结果整体均表现为标准的单峰型日循环形态，其中R_s↓与R_s↑变化同步，R_l↑、R_l↓滞后R_s↓0.5 ~ 1 h。各分量均表现出夏季高、春秋季次之、冬季低的季节波动性。干旱和极低的植被覆盖造成沙漠腹地全年潜热通量始终较为微弱，约占净辐射的2.8%，感热通量成为能量的主要消耗形式，约占净辐射的49%。偶尔的降水会刺激潜热通量突然增加。地表反照率相对较高且稳定，日变化呈早晚大、正午小的“U”型趋势，并具有明显的冬季高、夏季低的季节波动性，年均值0.28，月均值0.25~0.32。能量残差各月的日变化也均呈单峰曲线，日出后和日落前能量闭合程度最佳，并出现过闭合现象，全年夏季小，春秋季次之，冬季较大，月平均日峰值5.1~99.9 W·m^-2。土壤表层热储存是影响该地区能量平衡的重要因子之一，考虑表层土壤热存储后，地表能量闭合率达75.3%，能量闭合率夏季 > 春季 > 秋季 > 冬季，白天相比夜间有大幅提升。

Surface Radiation and Energy Balance in Hinterland of the Taklimakan Desert

In this paper, we analyzed the monthly mean diurnal variation characteristics of the surface radiation budget, energy flux and energy closure condition of the Tazhong shifting sandy land by use of surface radiation and turbulent flux data in 2013. The result indicated that except the LE, the monthly average daily variation of each component of surface radiation and energy balance showed the standard unimodal-type daily cycle pattern. Meanwhile, influenced by the difference of seasons, the daily variation curve had apparent seasonal variation characteristics, with every component manifested a feature of being the highest flux in summer, the second in spring and autumn, and the lowest in winter. From the perspective of energy distribution, the whole day LE in all seasons of the Tazhong shifting sandy land always occupied a relatively low percent, and in daytime, H was its main energy consumption form, second to which was G₀. However, the occasional rainfall could excite sudden increase of LE. The monthly average daily variation of surface albedo showed a U'shape distribution, and the surface albedo was small in summer and large in winter. The annual average surface albedo was 0.28, and the monthly average albedo varied from 0.25 to 0.32. Energy balance residuals appeared systematic diurnal cycle alternating with negative and positive value, and it was the lowest in summer, the second in spring and autumn, and the highest in winter. The monthly average daily variation peak value of energy balance residuals varied from 5.1 W·m^-2 to 99.9 W·m^-2. There was a significant change in the energy balance radio between before sunrise and after sunset and appeared instantaneous energy closure phenomenon. The soil heat storage between the surface and the flux plate was important for surface energy balance. The energy closure ratio was 75.3%, which was the highest in summer, spring took the second place, autumn took the third place and winter was the lowest, and better in the daytime than nighttime.