| The effect of the water-related disaster is more and more increasing with population growth, concentration and increasing value of assets in the flood plain in recent years. In the countries where river improvements are not sufficient, smooth evacuation from flooding is important for decreasing loss of life and properties. However, in reality, the development of flood forecasting and warning system in these countries has not advanced properly because of financial difficulty, lack of rainfall data, etc. In this context, global satellite-based rainfall mapping products is a key factor to encourage the implementation of flood forecasting system in such countries, because of their wide availability in the world for nothing through internet and their low maintenance cost for them. The only problems for their application to flood forecasting are the low accuracy of rainfall estimation and the lack of effective software to make it easy for developing countries to construct flood runoff analysis system in poorly-gauged basins.As the first step to improve the accuracy of satellite-based rainfall data using an engineering method, ICHARM proposes a self-modification algorithm without any ground-based rainfall truth data. The authors found a significant relationship between the degree of underestimation of heavy rainfall and the movement factor of rainfall field acquired by satellites. The empirical relationship was optimized for GSMaP data using flood events in the Shikoku Island of Japan and then was applied to some heavy rainfall events in the world. Then it was found the empirical formula was effective as well for the verification events as a whole. This method is effective only for heavy rainfall events at present, but the result is very promising for flood disaster mitigation since flood hazards usually occurs due to heavy rainfall.Besides, as a common toolkit software for the implementation of flood forecasting system in poorly-gauged basins in developing countries, ICHARM developed the Integrated Flood Analysis System, in short, IFAS. IFAS can contribute to the realization of the concept of GFAS-streamflow of IFNet, in any river basins of the world. |
