Detection of Local Climate Change by Studying of Freezing Days Fluctuations (Case Study Mashhad)

Subject Areas : Geopolitic

علیرضا  Shahabfar ¹ (ندارد)
سهراب  Mohammadnia ² (ندارد)
محمد  Motamedi ³ (ندارد)

Received: 2015-01-16 Accepted : 2015-01-16 Published : 2004-10-22

Keywords: Climate Change, Freezing Days, Fluctuation, Trend,

Abstract :

In this paper, for the aim of local climatic change detection, fluctuations of freezingdays in Mashhad during 1951-2000 were studied.Primary investigations showed that annual mean and absolute temperature have anincreasing trend in the study period. It has a suitable harmony to decreasing trend offreezing days. So, correlation equation between freezing days and statistical yearscalculated by this formula. Y=107.35X-0.53 which it was meaningful and shows –29.5 days changes in Annual freezing days in mentioned period. Using test of Mann-Kendal showed two decreasing and decreasing trend, which are significant. We canobserve a falling trend in number of freezing days after 1976.In next phase, for the purpose of fitting a suitable time series model on the data,which used in this research, the method of Box-Jenkins was applied. Finally after somestatistical works ARIMA (1,1,0) time series model was selected for the studied data.The model was able to predict the number of freezing days of Mashhad in the year2001 with an error about 3.3 percent.