Monitoring and Evaluation of Frost Indexes and Prediction of the Beginning of Autumn Frosts in Iran (Case Study: Hamedan Province)

In this research, in order to investigate the frosts occurred at Ekbatan station (Hamedan), the minimum daily temperatures of this station were studied. In general, the frosts were divided into three weak (mild), moderate, and severe categories. Next, the range of changes in the time of occurrence of these frosts was determined and the frequency of their occurrence was calculated. It was also attempted to obtain an experimental formula for the first autumn frost in a particular year based on the date of the last frosts of the spring of that year, and to determine the probability of occurrence of temperature thresholds between 0 and -15 ° C in different months of year by calculating different statistical parameters. In addition, it has been tried by dividing the the year into 36 distinct decades (ten days) to calculate the temperatures that are possible to occur with different percentages of probability.