Investigation of the Spatio-Temporal Variations in Atmosphere Thickness Pattern of Iran and the Middle East with Special Focus on Precipitation in Iran

Iman Rousta,Mehdi Doostkamian,Haraldur Ólafsson,Hamid Ghafarian Malamiri,Esmaeil Haghighi,Allah Taherian

doi:10.3390/cli5040082

Abstract

In this study, Geopotential Height (between 500 and 1000 hPa) and precipitation data were obtained from the NCEP/NCAR and IRIMO (Iran Meteorological Organization) for 60 years (1950–2010), respectively. Descriptive features of Atmospheric Thickness (hereafter AT) were calculated and analyzed by using the Mann-Kendall method. The results showed that the maximum AT was recorded in summer because of the dominance of the dynamic, hot subtropical high pressure. Furthermore, upper latitudes experienced more variations in terms of AT. The trend of variations showed that AT has significantly increased in recent years. Further, Saudi Arabia and the Red Sea experienced a more measurable increase in AT. On the other hand, AT had a declining trend over northern parts of Iraq and Iran, but it failed to be statistically considerable. The trend of AT had numerous variations over western parts of Iran, northwestern parts of Iraq, central and eastern parts of Turkey, and a large area of Syria. AT analysis of Iran’s precipitations showed that patterns in the Sea Level Pressure were caused by East Mediterranean, Sudan, and Saudi Arabia low pressures and the high pressures that were located in Europe and Kazakhstan. In addition, in upper-air (500 Hpa), the patterns were influenced by high Mediterranean trough and blocking phenomenon that come from higher latitudes.

Highlights

Thickness maps are frequently used in synoptic climatology
In January, the low average temperature has resulted in the shrinkage of atmosphere layers. This condition might be due to the fact that, in winter, the Middle East is influenced by various pressure systems (Red Sea low pressure, North African high pressure, Northeastern Iran high pressure, European high pressure, and North Caspian Sea high pressure), causing changes in its climate [49]
This study focused on analyzing AT in Iran and the Middle East

Summary

Introduction

Thickness maps are frequently used in synoptic climatology. These maps indicate the AtmosphericThickness (AT) between the two layers of 500 and 1000 hPa, which is represented as the thickness of the entire atmosphere [1]. Thickness maps are frequently used in synoptic climatology. 500- and 1000-mb pressure surfaces, is directly related to the mean temperature and water vapor path of an atmospheric layer [2]. Maps with the same thickness are indicative of places where cold or hot air is accumulated. Areas where contours are close together and have the lowest thickness are the regions in which cold air is accumulated. These regions represent low pressure areas on the earth and upper levels. Areas where contours are close together and have the highest thickness demonstrate regions

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Discussion

Conclusion