تحليلي آماري بر روند تغييرات دماي مشهد طي سده گذشته و رابطه آن با نوسانهاي اطلس شمالي

Statistical Analysis of Mashhad Temperature Trend in Recent Century and its Relation to NAO

Due to the importance of temperature increase and itʹs environmental and socio-economic effects on micro and macro planning, it has received much attention in scientific communities. Of these, is the effect on the behavior and pattern of pressure systems which is of global importance in changing NAO (North Atlantic Oscilliation) behavior in the last decades. Attempts have been made to investigate Mashhad temperature behavior and its relation to NAO by using statistical methods, ARIMA and transfer function models. There are three phases in the temperature and NAO time series that have relatively synchronized in time occurrence. In the last century Mashhad temperature has experienced an increase by 0.004495 ± 0.003992 °C while NAO trend has decreased by -0.001 + -0.00496. The best ARIMA model fitted to Mashhad temperature is ARIMA (0,1,1). It is clear that difference at lag l(d=l) in above model refers to a linear trend in the temperature mean. It is found that there is a relation between temperature change and NAO by 0,49, weighted in transfer function model. At last a linear 20 year prediction is computed for both ARIMA and transfer function models. As shown in the main text there is an increasing trend by 0.006 to 0.0068 °C per year.