drought is universal phenomenon that can occur everywhere and can cause harmful impacts on human beings and natural ecosystems. thus, it is very important to study drought character ristics part of for water resources management. in this study, the standardized precipitation index (spi) is used for drought frequency analysis in isfahan province. after collecting the precipitation data in the pr...

For land±atmosphere interaction studies several Topmodel based land-surface schemes have been proposed. For the implementation of such models over the continental (and global) scales, statistical properties of the topographic indices are derived using GTOPO30 (30-arc-second; 1 km resolution) DEM data for North America. River basins and drainage network extracted using this dataset are overlaid ...