The Atlas of Arid Zones in Latin America and The Caribbean (LAC) shows the final results of this initiative that includes the entire region, where more than 26 countries cooperated to create the map of arid, semi-arid and subhumid zones of LAC. Until present, the region did not present the same indicators on the availability of water resources in all countries, limiting a precise vision of the effective supply and demand that exists in each region from a climatic point of view. This is especially relevant in those countries where aridity gradients exist or those areas with water excess.

A standardized methodology applicable to all the Latin American and Caribbean sub-regions was developed within the project framework. Two types of analysis are included therein : a climatologic data analysis, using average data of normal periods (of 30 years) and a temporary variation analysis, using long-term historical precipitation series. The work process is broken down into the climatologic data collection and precipitation series and their transformation into a format that is compatible with the CIRH software (Agrimed, Universidad de Chile) that was specifically developed for the project, which automatically calculates several water regime indicators, including, among others, Evapotranspiration, Water Shortage and Surplus (DH and EH), the Precipitation Concentration Index (PCI) and the Modified Fournier Index (MFI).