Assessment of Drought and Trend of it's happening in Uremia

One of the natural phenomenon which occur in some areas (regions) of the earth is drought, although this phenomenon, drought, has very bad and harmful effects on water resources, agriculture, environment and etc., This crucial and intricate phenomenon has not been know well yet. In uremia, a research has been done so as to inspect the drought phenomenon and the process of its happening (how it occurs). To do this research, Standardized precipitation normal index and monthly precipitation of uremia station during (1 330-1 379) have been used. The periods, w b b the occurrence of drought has been examined, consists of 22 periods such as monthly, seasma& yearly/annually. The results of this research shows that wet year and drought have been olhwrad with different intensities during these periods; however, in some periods the conditions anert rt normal level. The most changes in summer and the least changes of coefficient in precipitadia take place in yearly (annually) period. It is better to know that the range of coefficient changes d monthly SPI happened in April. It seems that the process of drought and wet year follow nearly eleven-year-cycle. Mean while, more that one drought or wet year has been observed in tzd cycle with different densities.

کلیدواژه ها:

Drought ، Drought Cycle ، SPI index ، Precipitation Changes Coefficient ، Uremia