PRODUCTION AND FUNDAMENTAL VALIDATION OF GLOBAL SURFACE WATER MAP USING MULTIPLE MICROWAVE RADIOMETERS

抄録

 Information of surface water is necessary for flood disaster mitigation and the hydrological cycle studies. Normalized Differential Frequency Index (NDFI) was calculated by multiple microwave radiometers GMI and AMSR2 to produce a daily and 0.1-degree global surface water map for five years (2013–2017). Diurnal variation and bias between sensors in NDFI were adjusted. The basic performance of the surface water map was tested with global datasets. The five-year average NDFI and inundation ratio by Global Surface Water showed very high correlation around Japan. Monthly variation in NDFI and inundation ratio by Yesterday’s Earth at EORC showed positive correlation along some large river channels. NDFI showed a sudden increase at daily scale in some dry areas where daily variation in NDFI and antecedent precipitation index had positive correlation. These indicate that the increase in NDFI could be caused by inland water inundation rather than flood inundation.