摘要
地表蒸散影响着地表水分和能量的输送,在水文、气象、地理等诸多领域占有重要地位。该文首先基于大气辐射传输原理,利用MODIS大气产品提供的臭氧、水汽以及550nm气溶胶含量,运用大气透过率计算模型,进行了太阳总辐射的计算,均方根误差(RMSE)为61.4W/m2,相比FAO-56透过率模式112.1W/m2的误差有了明显改进。在此基础上结合MODIS的地表温度、植被指数产品进行了地表蒸散的计算。瞬时显热通量与郑州市大孔径闪烁仪(LAS)观测相比,有较好的一致性,RMSE为29.9W/m2。应用本文的透过率模型计算得到的日蒸散与观测值相比,RMSE为0.69mm,应用FAO-56透过率计算式得到的日蒸散RMSE为1.42mm。从验证结果来看,透过率的准确计算能够比较明显的提高地表蒸散计算精度。
Evapotranspiration(ET)affects the transportation of the water and energy of land surface.Based on the principle of the atmospheric radiative transferring,the instantaneous solar radiation was estimated firstly with an atmospheric transmittance model and the content of ozone,water vapor and aerosol optical thickness at 550 nm provided by MODIS products.The root mean square error(RMSE)of the incident solar radiation was 61.4 W/m 2,while it was 112.1 W/m2with FAO-56 transmittance function.Based on the transmittance model,land surface temperature,vegetation index of MODIS products were used to estimate land surface evapotranspiration.The results show that the instantaneous sensible heat flux has a good agreement with the observation of large aperture scintillometry(LAS)in Zhengzhou,and the RMSE was 29.9 W/m 2.The RMSE of daily ET estimated with atmospheric transmittance model was 73.2 W/m 2,while it was 107.1 W/m 2 with FAO-56 transmittance function.The precise estimation of transmittance can obviously improve the precision of ET estimation.
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2009年第S2期23-28,360,共7页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金(40501045)
国家支撑计划(2006BAD04B01-0101)
公益性行业(气象)科研专项经费项目(GYHY200706046)
欧盟计划FP7-ENV-2007-1(212921)
北京市重点实验室共建项目(000-105803)
关键词
遥感
蒸散
大气
透过率
MODIS
remote sensing,evapotranspiration,atmospherics,transmittance,MODIS
