中文摘要：

为了定量评估北京绿色奥运城市绿地建设对生态环境的改善作用,根据北京城市下垫面状况改进了SEBAL模型地表比辐射率、地表温度参数,应用模型对北京TM遥感图像反演了城市绿地水热通量,并用涡度相关系统地面同步观测数据进行验证,模型反演值与地面观测值基本相符.秋季植被覆盖下垫面显热约为建筑区的78%,为裸土的60%;而潜热约为建筑区的1.24倍,为裸土的1.55倍;林地显热约为草地的97%,潜热为草地的1.12倍.显热随植被覆盖度Pv的增加而降低,而潜热随Pv的增加而增加;在低植被覆盖度（Pv〈0.6）区域,提高Pv对降低显热、增加潜热的效果比高植被覆盖度（Pv〉0.6）区域要显著.

英文摘要：

To evaluate how the green space project ronment, SEBAL inputs, such as land surface emissivity of Beijing Green Olympics improve urban ecological enviand surface temperature, were modified regarding Beijing urban land surface. Water and heat fluxes over Beijing urban green space were retrieved from Landsat TM image based on SEBAL. As the flux output from SEBAL was validated with that measured by eddy covariance, there was reasonable agreement between them： Sensible heat flux（ Qh ） over vegetation is estimated to be 78% of that over building area, 60% of that over bare soil in autumn. Meanwhile, latent heat flux （ Qe ） over vegetation exceeds that over building area 1.24 times, that over bare soil 1.55 times. Qh over forest is estimated to be 97% of that o- ver lawn, and Qe exceeds that over lawn I. 12 times. Qh decreases while vegetation fraction（ Pv ） increases. How- ever, Qe increases with Pv increase. The flux increasing or decreasing effect against Pv is much more significant o- ver sparse plant cover area （ Pv 〈 0.6） than over dense plant cover area （ Pv 〉 0. 6）.