عنوان مقاله [English]
نویسندگان [English]چکیده [English]
The analysis of droughts in the water projects and also investigation on the relationship between climate and hydrological droughts is very important in the management of water resources. Therefore this study has been assessment the meteorological and hydrological drought adaptation from discharge and daily rainfall in the Sarab Seyed Ali watershed during a three-years period. At first for discharge data, the minimum of discharge monthly was calculated for each year, then with the using of Weibuoll distribution fitted to the data and were extended for a hundred-years period. Then corresponding values with return period of two years each month were selected as the drought threshold index. Threshold values were used for each month of daily data in a period of thirty years and drought severity was calculated based on their continuing. all the above steps were calculated for Precipitation data, With this difference that SPI was used for determining of climate drought index and finally between values of discharge and rainfall correlation was taken with the lag of 1,2,3 days. The obtained results showed that there are moderate and significant relationship between discharge and rainfall in the form of daily, monthly and seasonal and in all three modes, the relationship were enjoyed of significant level but the amount of correlation is more than the rest in the data without lag.