A “arid “climate is characterized by the fact that the middle annual potential evaporation lies more highly than the middle annual amount of precipitation.
A typical characteristic for an arid area is its Abflusslosigkeit. Rivers evaporate in their process completely, or they end in dischargeless lakes or salt pans.
With full aridity are present continuously dry climate conditions with less than 100 mm precipitation in the year, it prevail to aridity not only in the yearly expiration, but in each individual month.
A climate becomes “semiarid" genannt, wenn die betroffene Region zwar eine aride Jahresbilanz aufweist (Verdunstung > precipitation), during one period of three to five months however humid Verhältnisse herrschen (Niederschlag > evaporation).