ARIDITY, RISK CLIMATIC PHENOMENON IN DANUBE DELTA

Aridity is a major permanent risk for the climate of Danube Delta territory. Water resources and its quality are declining, and this is a severely limiting factor for both Danube Delta and the world, particularly with increasing aridity due to global warming predicted by some climate scenarios. Knowledge of aridity is also necessary to explain the characteristics of the geographical landscape for the rational use of water resources. Definition and characterization of aridity as intensity were done by several methods and indicators, starting with Lang's rain factor (1920), continuing with De Martonne’s aridity index (1926), Thornthwaite’s aridity index (1948), moisture deficit and ending with the UNESCO aridity index (1979). De Martonne’s aridity index (1926) was recently amended by Murai and Hund (1991) to match the classification of vegetation in the world, but its use in the international literature has not been implemented so far. Danube Delta ’s aridity is highlighted by all climatic aridity indices presented above; additional indicators can also be used. Increasing aridity in Danube Delta due to global warming is a real hazard, with the threat of desertification