Synoptic and Dynamic Analysis of Widespread Hot Days in Iran

Abstract

One of temperature status is high temperatures and occurrence of hot days. Surveying hot days and their atmospheric mechanism together with this event is an inevitable necessity regarding the importance of this temperature status. In the present paper, it is tried to recognize, classify and analyze the widespread hot days of Iran. For this purpose, two databases have been used in this study; Firstly, data base network of the state maximum temperature , these data are the outcome of interpolation of the beginning of 1961 up to the end of 2007. The second is atmospheric data including sea surface pressure( Hectopascal), zonal and meridian wind(M/S) and geopotential height(m). to study these data, an area between 10 ° of West longitude up to 120 ° of East longitude and 0° up to 80 ° of north Latitude was considered. During the statistical period ,1539 hot days have been identified. These days has been classified in to 4 categories by using cluster analysis. Analysis of atmospheric conditions together with these days showed that together with forming warm days , the regional low pressure and negative anomaly of pressure is possible in the country. So the wind direction from southern areas especially Saudi Arabia, Iraq and Africa in lower levels of the earth and even middle of the atmosphere , which is due to the height increase on Iran, has been observed. Surface and higher elevation heating has made the atmospheric sustainability, because the temperature difference of the two elevations and consequently the thermal vacation is decreased and stability of temperature status is expected.

Keywords

• hot day
• temperature advection
• widespread
• iran