MODIS近红外水汽产品的检验、改进及初步应用——以黑河流域金塔绿洲为例

利用野外观测资料检验MODIS近红外水汽产品表明,该产品精度较低,不适合研究区大气水汽含量分析研究.考虑误差产生的原因,调整空间分辨率并引入地表覆盖类型信息进行反演,结果表明,反演的平均相对误差为4.47%,绝对误差为0.0456g/cm2,说明改进后结果有较大改善,精度较高.同时使用MODTRAN模拟出大气水汽含量与透过率存在较好的负相关关系,并据此计算大气透过率,为下一步计算地表温度及能量平衡中的各分量奠定基础.

TESTING, IMPROVEMENT AND APPLICATION OF MODIS NEAR INFRARED WATER VAPOR PRODUCTS

MODIS near infrared water vapor products were tested by using the field observations which indicated that the precision of products should be improved and the products were not fit for application over the region.Considering the reasons inducing the error,we improved the algorithm and retrieved water vapor content by adjusting the spatial resolution and using the information of land use type.Our results show that the average relative error is 4.47%,and the average absolute error is only 0.0456 g/cm2,which indicates that the retrievals are much better than the products.By using MODTRAN to analyse,we find good negative correlative relationship between water vapor content and transmittance.According to the relationship,the transmittance was obtained which would be helpful to calculate the surface temperature and other energy parameters.