Estimate rice acreage in Hunan province using the China Environment Satellite data

For China, it is of great importance to be able to estimate the crop acreage in order to manage government agricultural subsidy system and guarantee food security. The objective of this study is to provide a technological support in rice acreage estimation for the country grain subsidy and investigate the potential of application of the China Environment Satellite HJ-1A/B in rice identification. For the southern rainy and cloudy regions of China, the SAR data have often been used to map paddy rice fields because they are independent of weather conditions and has all day imaging capability, but they may be obtained with high cost. In this research, the multi-temporal HJ-1A and B images at early-season rice growth stages in Hunan province were used for mapping rice fields and an algorithm for estimating paddy rice acreage was developed based on the arable coefficient and proportion of cloud to get high county accuracy. The mapping results were evaluated by field surveys and the promising identified accuracy was achieved with an accuracy of higher than 80% at county scale. The result of this study indicates that the algorithms we explored in the research is effective to estimate rice crop acreage and the HJ-1A/B has great potential in monitoring rice crop cultivation areas in southern China.