Estimation of global SCS curve numbers using satellite remote sensing and geospatial data

The Soil Conservation Service Curve Number (SCS CN) method is an efficient and widely used method for determining the direct runoff (effective rainfall) from a storm event for flood disaster assessment (rainfall-runoff modelling). The CN can be estimated based on the area's hydrologic soil group (HSG), land use/cover, and hydrologic condition. The two former factors are of greater importance in determining the CN value. This study reports an attempt to derive a global CN map. First, HSG was classified from digital soil maps. Second, CN was estimated as a function of HSG, land-cover classification, and hydrologic conditions according to USDA (1986) and NEH-4 (1997) standard lookup tables. Potential applications of this CN map may include real-time global flood assessment by incorporating an operational multisatellite precipitation estimation system (e.g. http://trmm.gsfc.nasa.gov).