Abstract:This paper is aimed to extract the paddy rice area of Jiangsu,Anhui and Jiangxi provinces in 2010 by using multi-temporal MODIS imagery,and to investigate the efficiency of Fast Independent Component Analysis(FastICA) algorithm in dealing with mixed pixels.In order to map the paddy rice area,the time series of Land Surface Water Content Index(ILSW) and Normalized Difference Vegetation Index(INDV) are first produced from MODIS data.Then they are smoothed in order to reduce contamination by clouds.Meanwhile,the pixels with non-crop classes are removed from the index-images using the Land Cover Type data,which is one of the public-distributed MODIS products.The mapping accuracy of the paddy rice area is always affected by the spatial variation of rice planting schedules and rice species.To solve this issue,Rice Similarity Index(RSI) is calculated from INDV and used to establish standard rice growing curves for different parts of the study area according to the field survey.Combining the standard rice growing curves and the time series of index-images,a rice mapping algorithm is developed and performed to extract the rice planting area.The results show that the obtained rice distribution map is well consistent with the actual situation.However,the retrieved rice planting area is overestimated in most part of the study area,which can be primarily ascribed to the mixed pixels.In this paper,the FastICA algorithm is adopted to decompose the mixed pixels using time series of INDV.Before applying the FastICA algorithm,the images of times series of INDV are masked by the obtained paddy rice map.Menwhile,several parameters of the FastICA are optimized by comparisons.As a result,a map of paddy rice abundance fraction is retrieved for each province by FastICA.According to the analysis and comparison with the statistic data,the average accuracies of the obtained rice area are 86.4%,87.9% and 51.5% in Jiangsu,Anhui and Jiangxi provinces,respectively.The larger area error in Jiangxi province can be ascribed to the great proportion of the paddy fields located in the mountainous area.