Estimation Of Late Spring Cold And Early: Autumn Freezing For Some Crops In Charmahal And Bakhtiari Province

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Abstract

This research was conducted to estimate the late spring cold and early autumn freezing for some crops in Charmahal and Bakhtiari province. Data on time occurrence of daily temperature in different ranges including (0-1), (-1-3) and less than -3° C, absolute minimum temperature and the first and last temperature lower than zero in autumn and spring respectively, were obtained from several metheorological stations in Shahre Kord, Pole Zamankhan, Boroujen, Lordegan and Koohrang. Then, data were modeled by using different distribution functions like normal, 2-parameter lognormal, 3-parameter lognormal, Pearson type III, logpearson type III, Gumbel and Gamma. The best distribution function was selected based on the residual sum of squares. Knowing the proper distribution function, the probability of occurrence of spring cold and autumn freezing was estimated for different locations.

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