Digital Atlas of World Water Balance

As many of the data sets were compiled for that project, they were drawn from data sets of global extent, so we decided to compile the global data into one location and add to that the data files and sample exercises that we had produced in our work on the Water Balance of Africa, to form a product with which similar tasks could be accomplished for other parts of the world. Some of the exercises were developed during a Technical Cooperation Project on the Souss Basin in Morocco in collaboration with the Direction Generale de l'Hydraulique of Morocco.

Additional applications have been made to the Urubamba River Basin in Peru, and to the Aral Sea Basin in Central Asia.The data and exercises which support this Digital Atlas are designed to be used with the Arcview Version 3.0 Geographic Information System, though Version 2.1 can be used for many of the exercises. The descriptive material contains graphic files, some of them animated, which explain the origin and processing of the data.

The Water Balance of the Niger Basin paper, explains the background and methodology This Digital Atlas contains five types of data: precipitation, temperature,radiation, runoff and political boundaries. The precipitation, temperature and radiation data are depicted on a 0.5 degree grid spanning the earth (720 cells East-West, and 360 cells North-South, or 259,200 cells in all), covering both the land surface and the oceans.

On each grid cell is presented the mean monthly and mean annual values of each variable in Arcview shapefiles. More information on these data can be found in the section on Data Sources. Mean monthly and mean annual runoff at 160 stations are found in the runoff directory.

The political boundaries are used to delimit particular regions of interest in the data sets.