The effect of heat waves on the intensification of the heat island of Iran's metropolises (Tehran, Mashhad, Tabriz, Ahvaz)

Abstract

The present research studies the occurrence and analysis of heat waves and their effect on the heat island of the metropolises. An average of 43–51 heat waves occurred in the statistical period in the metropolitan area. During the night, the effect of the heat island in the metropolises can be observed obviously. In the metropolis of Mashhad, Ahvaz, Tabriz and Tehran, respectively, at the time of the occurrence of a warm wave height and severity of the thermal island about 4, 4,6 and 3 °C, respectively, were added to the days of non-occurrence of the wave.The synoptic analysis conducted on the 4 patterns leading to heat wave on metropolises shows that the low pressure of Pakistan is the main reason for the hot advection of the lower layer of troposphere in Mashhad and low pressure in Saudi Arabia has been the main reason of hot advection of the lower layer of troposphere of the metropolitan areas of Ahvaz, Tehran and Tabriz. In the middle layer of troposphere, in all of the above metropolises, the expansion of the anticyclone ridge of Saudi Arabia on the region is the main cause of the air subsidence.