Skip to main content
U.S. flag

An official website of the United States government

Basin level statistical properties of topographic index for North America

May 1, 2000

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 on computed topographic indices for the continent and statistics are extracted for each basin. A total of 5020 basins are used to cover the entire continent with an average basin size of 3640 km2. Typically, the first three statistical moments of the distribution of the topographic indices for each basin are required for modeling. Departures of these statistical moments to those obtained using high resolution data have important implications for the prediction of soil-moisture states in the hydrologic models and consequently on the dynamics of the land–atmosphere interaction. It is found that a simple relationship between the statistics obtained at the 1 km and 90 m resolutions can be developed. The mean, standard deviation, skewness, L-scale and L-skewness all show approximate linear relationships between the two resolutions making it possible to use the moment estimates from the GTOPO30 data for hydrologic studies by applying a simple linear downscaling scheme. This significantly increases the utility value of the GTOPO30 datasets for hydrologic modeling studies.

 

Publication Year 2000
Title Basin level statistical properties of topographic index for North America
DOI 10.1016/S0309-1708(99)00049-4
Authors Praveen Kumar, Kristine L. Verdin, Susan K. Greenlee
Publication Type Article
Publication Subtype Journal Article
Series Title Advances in Water Resources
Index ID 70156747
Record Source USGS Publications Warehouse
USGS Organization Earth Resources Observation and Science (EROS) Center
Was this page helpful?