The Investigation of Summer Heat Waves in Tehran City

Abstract

Temperature change trend has been rising in recent years and these changes in areas such as Iran which is located on arid and semi arid belt of world is more impressive. In this research heat waves with different continuations have been studied for Tehran metropolis in a 5 years period (2010-2015). Statistical data of mean daily temperature of synoptic stations of Tehran in the summer were selected and then a few continuing days temperature that were higher temperature trend than mean temperatures of before and after days defined as a heat wave that had continuation of 3 to 6 days. After extraction the days with heat wave, synoptic maps of geo potential and humidity, as well as indexes, charts Skew T of days for governing phenomenon were provided. The results showed that most of the heat wave phenomena have happened in July. In the terms of synoptic view, the occurrence time of this phenomenon in most cases has been when high pressure subtropical prevailed and has higher elevations than its mean long-term and has created a stable atmosphere for the Tehran metropolitan. On the other hand tabs of moisture have entered below the surface of the high-pressure to atmosphere of region has been caused the temperature increase and intensify it.

DOI: 10.5901/mjss.2016.v7n3s2p216