: Transition zones with enough moisture for grass and some crops; covers 12.2% of global land. Drivers and Ecological Impact
: Limited rainfall and specialized vegetation; covers 14.6% of global land. aridity
Aridity is a permanent climatic feature of regions where the long-term average water supply (precipitation) is significantly lower than the atmospheric demand for water (potential evapotranspiration). Unlike drought, which is a temporary and anomalous period of moisture deficit, aridity is a chronic state of water scarcity that defines the very character of an ecosystem. It is primarily measured using the , calculated as the ratio of annual precipitation to potential evapotranspiration. Classification of Arid Environments : Transition zones with enough moisture for grass
Aridity: Understanding the Long-Term State of Water Scarcity aridity