| Food is extremely important worldwide. Estimation of Crop grain yield is one of important information of national economy, especially after our country joining the WTO. Our country has more population, so it is more important to solve the food of 1.3 billion populations (forecasting 1.6 billion in 2030). Rice is the most important staple crop in China. After reform and open policy, especially the open policy of grain yield production has brought more change. So, estimation of rice yield using satellite remote sensed data has more significance in grasping food information and security of food.Four periods can be divided in the investigation of rice yield estimation using remote sensing data carried out by Institute of Agricultural Remote Sensing & Information Application of Zhejiang University: preliminary experimentation of rice yield remote sensing mechanism from 1983 to 1988; the study on technical and economic possibility from 1989 to 1990; the study on the technical problem by associating with some other units from 1991 to 1996; the study on the development and application for the rice yield estimation system of Zhejiang province using remote sensing data from 1997 to 1999; the operational experiment from 1999-2002, the problem between the fundamental accuracy and economic burden of the users had been solved, and the operational system of rice yield estimation using remote sensing data in Zhejiang province was established.But in recent year, with the economic development, the agricultural restructuring, and fast development of agricultural town, the lessening of rice area brought about instability of accuracy of rice estimation using remote sensing. At the same time, with the emergence of new sensor and new remote sensing technology, NOAA/AVHRRwill be instead of Moderate-Resolution Imaging Spectroradiometer (MODIS) after several years. Considering these problems, it became more important that supplement and perfection of rice yield estimation system using remote sensing data and study on the mechanism and methods of accuracy stability for MODIS data improving rice yield estimation.With the success of launch of TERRA on Oct. 18, 1999, it indicated the beginning of new milestone of observing the earth, just as the description of NASA introducing the TERRA satellite: "if the earth is regarded as a middle-aged person who have never been checked, TERRA is the scientific tool which scientists first check the health of earth with history of 4.5 billion year.The MODIS instrument inboard NASA's Terra satellite is a scanning radiometer system with 36 spectral bands extending from the visible to the thermal infrared wavelengths. The first seven bands are designed primarily for remote sensing of land surface with spatial resolutions of 250m for band 1 and band 2, and 500m for bands3 to 7, the other bands are 1000m, where the repeat frequency is approximately 1-2 days. MODIS provides more products including land surface reflectance, surface temperature, vegetation index, and leaf area index etc. These products avoid complex procedure and can meet the need of every model, in addition MODIS will provide free data of 15 year. With more products provided by MODIS, validation and application of MODIS have started and become an active research field. However, more research focused on the forest, grassland etc.MODIS will be used instead of AVHRR, and abundant products of MODIS provide better remote sensing data for improving the accuracy stability of rice yield estimation. However more problems such as mechanism and methods of improving the rice yield estimation must be firstly solved.According to above problems, basing on the operational system of rice yield estimation by RS in Zhejiang province, utilizing products of MODIS and more field observed data, from every aspects such as characteristics, calculating principles and methods of MODIS and comparison and validation of different sensors etc, the mechanism and methods of accuracy stability for MODIS data improving rice yield estimation have been studied, the main contents of this...
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