青藏高原地区地表能量通量的估算与验证对高原及其周边地区能量和水循环研究具有重要意义,地表能量平衡系统SEBS(Surface Energy Balance System)模型为研究高原非均匀地表区域地表能量通量提供了一种行之有效的方法。基于中国科学院那曲高寒气候环境观测研究站(简称那曲站) 、中国科学院纳木错多圈层综合观测研究站(简称纳木错站)和中国科学院珠穆朗玛大气与环境综合观测研究站(简称珠峰站) 2008年辐射资料、大气边界层塔站观测资料,结合MODIS卫星数据,利用SEBS模型估算地表能量通量,并用站点地表能量通量观测资料进行验证。结果表明,模型估算的感热通量和土壤热通量与站点实测值具有较好的一致性,且感热通量和土壤热通量的估算精度明显优于潜热通量;感热通量的估算精度最高,那曲站、纳木错站和珠峰站的均方根误差分别为54.98, 37.37和27.10 W·m~(-2);而模型估算的潜热通量验证结果偏差较大和站点实测数据存在能量不闭合问题相关。鉴于在地表能量通量观测中广泛存在能量不闭合的问题,利用波文比校正方法校正站点实测潜热通量。研究表明波文比校正方法可以明显改善地表通量观测数据能量不闭合的问题,那曲站、纳木错站和珠峰站的能量闭合率分别提高了19.4%,21.4%和19.1%;与原始站点实测潜热通量相比,校正后的潜热通量与SEBS模型估算结果一致性较好,3个站点潜热通量的均方根误差分别减少了6.78,33.48和29.30 W·m~(-2)。
英文摘要:
The surface energy fluxes occur near the ground and are pivotal parameters for studying land-atmosphere interaction. The Qinghai-Tibetan Plateau is one of the most sensitive regions in response to global climate change. Its thermal and dynamic effects on the atmosphere are mainly achieved through the exchange of heat and water vapor between the land surface and the atmosphere. The estimation and validation of the surface energy fluxes over the Tibetan Plateau have great significance on the study of energy and water cycle in the Qinghai-Tibetan Plateau and its surrounding regions. The surface energy balance system (SEBS) model provides an effective method for studying the surface energy fluxes over the heterogeneous underlying surface. In order to further explore applicability of the model estimation for the typical underlying surface over the Tibetan Plateau,based on in-situ radiation data and Atmospheric Boundary Layer (ABL) tower data (Nagqu Station of Plateau Climate and Environment (BJ), Nam Co Station for Multisphere Observation and Research (Nam Co) and Qomolangma Station for Atmospheric Environmental Observation and Research (QOMS), Chinese Academy of Sciences (CAS)) and combined with MODIS data in 2008,the SEBS model was used to estimate the surface energy fluxes which were validated with the in-situ measurements. The results showed that the sensible heat flux and soil heat flux estimated by the model were in good agreement with the in-situ measurements,and the estimation accuracy of sensible heat flux and soil heat flux was obviously better than that of latent heat flux. The estimation accuracy of the sensible heat flux was the highest,and their root mean square error (stations BJ,Nam Co and QOMS) were 54.98 W·m~(-2),37.37 W·m~(-2),27.10 W·m~(-2),respectively. The error of the latent heat flux of the model estimated is relatively large,which is caused by the energy closure problem in the in-situ measurements. Taking the imbalance of energy closure prevails in most surface energy fluxes measurements into account, the latent heat flux measurements were corrected by using the Bowen ratio correction method. Results showed that the Bowen ratio correction method could significantly improve the energy imbalance problem. The closure ratios of surface energy balance (stations BJ,Nam Co and QOMS) were increased by 19.4%、21.4%、19.1%,respectively. Accordingly,the corrected latent heat flux had better consistency with model estimation results. The root mean square error of estimated latent heat flux decreased by 6.78 W·m~(-2)(BJ), 33.48 W·m~(-2)(Nam Co), 29.30 W·m~(-2)(QOMS), respectively.