Satellite-based mapping of paddy rice agriculture in Asia

Paddy rice fields are distributed throughout the Asia and serve as a main food source for billions of people in Asia. One unique feature of paddy rice fields is that they have a layer of surface water to cover soils, and consequently it acts as a major source of methane emissions and plays an important role in global atmospheric methane budget. Flooding (irrigation) of paddy rice fields consumes large amounts of water. Intermittent drainage of paddy rice fields is widely practiced by farmers as a way for enhancing plant growth and increasing rice crop yield. Changes in spatial distribution of paddy rice fields and temporal management of water (flooding/drainage) in paddy rice fields are likely to have significant impacts on food production and trace gases emissions. Here we present an effort to develop novel approaches for identifying and mapping paddy rice fields in Asia. The 8-day composites of MODIS in 2002 and ancillary data are used in geospatial data analysis. Our objective is to generate geospatial database of paddy rice fields at 500-m spatial resolution for Asia, including the spatial distribution of paddy rice fields, timing of transplanting and harvesting, and water management (flooding and drainage). The resultant geospatial database is likely to serve many applications, including the carbon cycle, trace gases emissions, and water management