Increasing accuracy of regional rice yield estimation by improvement of spatial resolution of leaf area index maps in VSM vegetative model

Mokhtari, Sheida; Pirmoradian, Nader; Vazifehdoost, Majid; Davatgar, Naser

Increasing accuracy of regional rice yield estimation by improvement of spatial resolution of leaf area index maps in VSM vegetative model

Document Type : Research Paper

Authors

¹ Graduate Student, Dept. of Water Engineering, Faculty of Agricultural Sciences, University of Guilan

² Assist. Prof., Dept. of Water Engineering, Faculty of Agricultural Sciences, University of Guilan

³ Research Assist. Prof., Rice Research Institute of Iran

Abstract

VSM is a simple vegetative simulation model which in spite of needs to a few input data, its accuracy in field scale is acceptable. However due to high uncertainty in input data, its application in regional studies is very limited. In this study, the regional rice estimation was improved by combining VSM model with satellite data of short wave solar radiation and leaf area index. The spatial resolution of remotely sensed leaf area index from MODIS was improved using downscaling technique and high spatial satellite data of Landsat TM. Later its impact was investigated on validation process of regional rice estimation. Comparison of observed and estimated LAI with (or without) downscaling indicated that in case of applying down scaling technique accuracy of LAI maps will increase up to two times (from R²= 0.44 to R²= 0.87). The results indicated also in case of using downscaled LAI data in VSM model, the overall accuracy of regional rice yield estimation will increase dramatically (from R²= 0.64 to R²= 0.91).

Keywords