MODIS大气产品的光合有效辐射估算研究

Estimating photosynthetic active radiation using MODIS atmosphere products

利用气溶胶、水汽、云以及臭氧等MODIS标准大气产品,在简单辐射传输模型基础上估算青藏高原光合有效辐射,经验证估算的光合有效辐射与实测数据存在显著的线性相关,相关系数在0.8—0.9之间,最大误差为13%。经过敏感性分析发现云层厚度、气溶胶含量以及大气压力对光合有效辐射的影响大。臭氧和水汽含量的变化不敏感。云层厚度、Angstrom浑浊度系数和大气压力分别变化30%、25%和15%时,光合有效辐射变化分别为20%、5%和5%。

This study estimates photosynthetic active radiation（PAR） based on a simplification of the general radiative transfer equations and Moderate Resolution Imaging Spectroradiometer（MODIS） atmosphere products（aerosol,cloud,ozone and water vapor product）.Comparing estimated PAR with field measurements in Tibetan Plateau in 2005,significant linear correlation in order 0.8—0.9 is obtained and relative error is less than 13%.Remaining other condition constant in sensitive analysis,cloud thickness,depth of aerosol and pressure show more important impacts on PAR estimation than water vapor and ozone.Cloud thickness,angstrom turbidity coefficient,atmospheric pressure changes by 30%,25% and 15% will lead to respective changes in PAR of 20%,5% and 5%.