بررسي خشكسالي ها - ترسالي ها و امكان پيش بيني آنها با استفاده از مدل سري زماني هالت وينترز در استان هرمزگان

Study of Dry-wet Periods and Possibility of Forcasting Them by Using Holt-Winters Time Series Model in Hormozgan Provience

This research has been done in part of Hormozgan provience, O study time variations in precipitation, and to survey drywet periods and the possibility of forcasting them in future. We used Z standard Index to calculate drought, wetness, duration, and the rate of precipitation. Then, by using Time Series Holt Winters Model, we predicted the weather for the following years. Monthly rain data of three synoptic stations were used: Bandar Abas, Minab and Bandar Lengeh, during thirty seven (19662002) years.Results indicate the occurance of three drought and two wet periods. It was also revealed that droughts will be weak or medium with long duration, while wet years will be of short life. Based on Time Series Holt Winters Model, the investigation of the observed and predicted data values, shows two decrease and increaa sinuous cycles. The first includes 20, (1966-1985), and the second 17, (1986-2002), years; prediction of the decrease of the next two years, almost completes this cycle.