Global Humidity Index

The Global Humidity Index is based on a ratio of annual precipitation and potential evapotranspiration as P/PET, and largely follows the classification used in a 1984 UNESCO study. The Global Humidity Index surface shows mean annual potential moisture availability for the period 1951-1980, classified into four aridity zones and one humid zone, defined in this data set as follows: Hyper-Arid Zone (P/PET less than 0.05), Arid Zone (0.05 less equal P/PET less than 0.20), Semi-Arid Zone (0.20 less equal P/PET less than 0.50), Dry-Subhumid Zone (0.50 less equal P/PET less than 0.65), and Humid Zone (0.65 less equal P/PET). Download the selected data dynamically from the Environmental Data Explorer server in ArcInfo e00 format.