Grid with average Wet Day Frequency (rain days per month) for the period 1961-1990. This dataset is constructed from observations, backed with synthetic data derived from precipitation. Source: New, M., Lister, D., Hulme, M. and Makin, I., 2002: A high-resolution data set of surface climate over global land areas. Climate Research 21:1-25

Grids with monthly values of coefficient of variation of precipitation for the period 1961-1990, at 5 arc min. Based on: New, M., Lister, D., Hulme, M. and Makin, I., 2002: A high-resolution data set of surface climate over global land areas. Climate Research 21:1-25

Grid of estimated aridity with a spatial resolution of 10 arc minutes. This dataset represents average yearly precipitation divided by average yearly potential evapotranspiration, an aridity index defined by the United Nations Environmental Programme (UNEP). The classification of the aridity index is: - Classification Aridity Index Global land area - Hyperarid AI < 0.05 - 7.5% of the global land area - Arid 0.05 < AI < 0.20 - 12.1% of the global land area - Semi-arid 0.20 < AI < 0.50 - 17.7% of the global land area - Dry subhumid 0.50 < AI < 0.65 - 9.9% of the global land area

Grid with estimated yearly precipitation with a spatial resolution of 10 arc minutes. The dataset contains average values for global land areas, excluding Antarctica, for the period 1961-1990. The dataset has been prepared according to the FAO Penman - Monteith method with limited climatic data as described in FAO Irrigation and Drainage Paper 56. The dataset consists one ASCII-grid with yearly data in mm/year. ASCII-grids with mean monthly data in mm/day * 10 are also available as described in the associated resources of this metadata.

Grid with estimated precipitation per month with a spatial resolution of 10 arc minutes. This dataset has been constructed from 27 075 stations with 1961-1990 climatological normals. The dataset consists of 12 ASCII-grids with mean monthly data in mm/day * 10, and one ASCII-grid with yearly data in mm/year. In addition, 12 ASCII-grid with monthly values at 5 arc minutes resolution are made available as input data for a global water balance model (GlobWat).