干旱区荒漠下垫面能量通量观测误差对能量闭合的影响

Impact of Observation Error of Desert Underlying Surface Energy Flux on Energy Closure in Arid Area

利用内蒙古微气象观测试验（IM-Mm OE）资料,分析干旱区荒漠下垫面近地层能量传输特征,探究观测仪器的一致性问题及其对地表能量平衡的影响。结果表明：干旱区荒漠下垫面的能量传输以感热和地表土壤热通量为主。大多数辐射仪器的观测相关系数大于0.98,地表土壤热通量和感热通量的观测相关系数大于0.97,潜热通量观测相关性最差,为0.92,其中地表土壤热通量、感热通量和潜热通量的均方差分别为14.3 W·m-2、8.9 W·m-2和8.0 W·m-2,各仪器之间观测数据比较一致,观测误差较小。非一致性引起的观测数据偏差直接影响能量闭合率,试验中湍流通量（感热通量和潜热通量之和）的观测偏差造成地表能量闭合率1%3%的不确定性,有效能量（净辐射与地表土壤热通量之差,仅考虑地表土壤热通量的观测偏差）造成5%的不确定性,湍流通量和有效能量两者数据的总偏差造成地表能量闭合率6%8%的不确定性。

In this paper,the characteristics of the energy transmission near the surface layer over desert substantial underlying surface in arid area were analyzed,the study was carried out with the observation instruments,and the influence of these instruments on the surface energy balance was researched based on the observed data obtained from the Inner Mongolia Micro meteorological Observation Experiment（ IM-Mm OE）. In designing the experiment,the observed inconsistent impact on energy closure was maximized as much as possible. The ideal underlying surface for the observation should be homogeneous,but the actual one was inhomogeneous,so the observation precision of surface energy flux was not reached an ideal level,and the influence of observation errors on the surface energy closure was widely concerned. The results showed that the surface energy transfer in the desert underlying surface in arid area was mainly dominated by sensible heat flux and surface soli heat flux. The observed correlation coefficients of the most radiation instruments were higher than 0. 98,the correlation coefficients of observed surface soil heat flux and sensible heat flux were higher than 0. 97,and the correlation coefficient of observed latent heat flux was the lowest and only 0. 92. The mean squared errors of surface soil heat flux,latent heat flux and sensible heat flux were 14. 3 W·m-2,8. 9 W·m-2 and 8. 0 W·m-2 respectively,the observed data of all the instrument were consistent well,and the observation errors were low. Deviations of the observed data caused by the nonuniformity could affect directly the rate of energy closure,the observed deviations of turbulent flux（ the sum of sensible heat flux and latent heat flux） caused an uncertainty of 1%-3% of the surface energy closure rate,the effective energy（ the difference between net radiation and surface soil heat flux,the deviation of observed surface soil heat flux was considered only） brought about an uncertainty of 5%,and the total deviation of the data of turbulent flux and effective energy resulted in an uncertainty of 6%-8% of surface energy.