Satellite estimation of photosynthetically active radiation in Jiangxi Province

Abstract

Incident photosynthetically active radiation (PAR) is a key variable needed by almost all terrestrial ecosystem models. Unfortunately, the current incident PAR products estimated from remotely sensed data at spatial and temporal resolutions are not sufficient for carbon cycle modeling and various applications. In this study, the author improved Eck and Dye model which is a PAR simulating model using ultraviolet reflectance. The advantage of the ultraviolet over existing visible band approaches to estimating insolation is the improved ability to discriminate clouds from high-albedo background surfaces. Ultraviolet spectral reflectance data from the Total Ozone Mapping Spectrometer(TOMS) was used to test the approach for Qianyanzhou station, southeast of China. Estimates of 8-day composition total incident PAR from the satellite technique differed from measurement values by higher than 3.47%. The incident PAR over Jiangxi Province was mapped in 2003 and 2004. The results indicate that this approach can produce reasonable PAR product and is suitable for regional and global applications, although more quantitative validation activities are still needed.