The Analysis of Freezing Fluctuations and Thresholds of Fall and Spring Seasons in Ahar Township

Freezing is a situation in which the air temperature drops below zero degrees centigrade. An accurate knowledge on the fluctuations of freezing dates can help us protect daily agricultural activities, particularly those being sensitive for temperature fluctuations. In this paper, we have studied the fluctuations in freezing dates of the first freezing of the fall and the last freezing of winter seasons in 4 temperature thresholds of A= (-2.2 to zero), B= (-2.2 to -4.4), C= (-4.4 to -6.6), and D= (-6.6 and lower) of Ahar township for a 20 year period. After extracting the dates of first and last freezing dates of fall and winter seasons respectively, we established the first day of Persian month (Mehr) as the basis for Julius calendar, then calculated the daily freezing amounts on the above-mentioned thresholds. The normality of the data was confirmed with a confidence level of 95%, and the freezing occurrence dates were also determined in different confidence limits of 99.9%, 95%, 90%, 80%, and 60%.