The temporal analysis and forecasting models of low extreme temperatures for Tehran

In this study the data relating to the absolute minimum daily temperatures of Tehran MehrAbad synoptic station during the statistical period of 1951-2010 (60 years) have been used. The Regression models (including Logarithmic and Polynomial) along with Mann-Kendal statistic were employed for detecting the significance of trends. The results of this study indicated meaningful and significant changes in extreme values of long term minimum temperatures of Tehran mehrabad station. However, these results explained that the low extreme temperatures of Tehran mehrabad station have been influenced by the commencement of the cold start and the trend has changed since 1970. The change detection results of the trend of changes in low extreme temperatures of Tehran mehrabad station proved to be positive. This is an indication of the reduction of severity of cold season and it’s approaching toward a moderate situation. This study showed that the Halt-Winter model is best method for forecasting future low extreme temperatures of Tehran Mehrabad station. The forecasted results of low extreme temperatures of Tehran shows that the low extreme temperature of Tehran at least in 2013 and 2020 will moderate to the top of zero. Considering that this significant ascending trend in Tehran low extreme temperatures are expectable and indicate gentle winter climate in the next 10 years.