Rice monitoring in China - Mid-term report

This paper summarises the objectives of the project, the works undertaken, the results obtained, and outlines the next steps of the project. The objective of the project is to develop methodology to use ENVISAT data for rice mapping and retrieving information characterising rice fields (biomass, photosynthetical activities, water management status) relevant to the modelling of rice growth. The overall goal is the estimation of rice production at local and regional scale and the estimation of the Carbon fluxes (CO2, CH4) at regional scale. In the first phase of the study, remote sensing methodology is developed at selected test areas for rice mapping and retrieving of rice parameters. The activities include ground data collection and analysis of remote sensing data. Meantime, preliminary works on large scale crop modelling in China have been undertaken. The results obtained using ENVISAT data in 2004 and 2005 at the test areas in Jiangsu province indicate that it is possible 1) to map rice fields at a single date using two polarisations of ASAR APP, 2) to retrieve rice biomass using the polarisation ratio, 3) to map the main rice varieties, 4) to achieve regional rice mapping using multidate ASAR WideSwath data, and 5) to detect intermittent drainage. These new findings, still to be validated and confirmed, show great potential for statistics of rice growth areas, and in providing the essential information for the modelling of rice growth. ENVISAT ASAR data are expected in 2006, for a demonstration of the methodology, at least at a regional scale, and for an integration of remote sensing in crop modelling.