Quantitative study of net radiation from MODIS data in the lower boundary layer in Poyang Lake area of Jiangxi Province, China

Abstract

This paper focuses on quantitative calculation of longwave radiation and shortwave radiation from MODIS data in the Poyang Lake area of Jiangxi Province, China. The sum of the net longwave radiation and the shortwave radiation is the net radiation. These parameters are critical for the study of energy exchange in the lower boundary layer on land surface. Two of the most important factors for the retrieval of longwave radiation are the land surface temperature and emissivity. In this paper, the land surface temperature and emissivity were calculated from MODIS data using the regional self‐iterative split‐window method. The most important factor in the determination of the shortwave radiation is Earth surface albedo. The spectral reflectance and surface albedo were derived from MODIS data using the Synergy of TERRA and AQUA MODIS data (SYNTAM) algorithm. The net shortwave and longwave radiation were calculated and compared with the in situ measurement data. Our results indicate that the methods for quantitative calculation of net longwave radiation, shortwave radiation and net radiation from MODIS data can have a good accuracy. The relative errors are between 2.1% to 9.72% for longwave radiation, 0.15% to 10.48% for shortwave radiation and 0.64% to 13.7% for net radiation. We can conclude that a good accuracy can be achieved for deriving longwave radiation, shortwave radiation and net radiation, which are helpful for heat exchange, environmental, hydrology and ecology research in land areas.

Acknowledgements

This publication is an output from the research projects “Grid platform based aerosol fast monitoring modeling using MODIS data and middlewares development” (40471091) funded by National Natural Science Foundation of China (NSFC), China, “Dynamic Monitoring of Beijing Olympic Environment Using Remote Sensing” (2002BA904B07‐2) and “863 Program ‐ Remote Sensing Information Processing and Service Node” (2003AA11135110) funded by the MOST, China and “Digital Earth” (KZCX2‐312) funded by Chinese Academy of Sciences, China. The authors would like to express their thanks to Beijing Normal University for supplying the in situ temperature data and the financial support by the Opening Foundation of Key Laboratory of Poyang Lake Ecological Environment and Resource Development (Jiangxi Normal University) on the project “Boundary Layer Energy Exchange Study from Remote Sensing Data” (PK2004013).