Review of Iran's Climatic Zoning Based on Some Climate Variables

Abstract

In this study, the average climate data of meteorological stations including temperatures of the warmest and coldest months of the year, precipitation regime, potential evapotranspiration and UNEP aridity index has been used to map Iran's climate zones. In this regard, climate variable of air temperature, relative humidity, potential evapotranspiration, and precipitation characteristics of 303 meteorological stations throughout Iran was used on monthly and annual time’s scales. The annual aridity index in each site was calculated using the United Nations Environment Program (UNEP) index. Then, the temperature characteristics of the warmest and coldest months of the year were coded. Results show a very high climatic diversity throughout Iran. In this model, Iran's climate was divided into 27 categories. Based on aridity index, Iran has seven climates zones. There are 30 cities with hyper-arid climate. This climate type has three climate territories and occupies about 3.4 percent of the country's territory. The arid zone with five climate territories cover about 23.7 percent of the country and dominates 95 cities. The semi-arid climate with 6 climatic territories accounts for about 39.6 percent and dominates 113 cities. The dry sub-humid zone with four climate territories and covers about 17.3 percent and dominates 30 cities. Nine cities have a semi-humid climate with three climatic territories which accounts for about 8.9%. The humid climate with four climate territories covers about 5.8 % and dominates 13 cities. The very humid climate with 2 climatic territories accounts for about 1.3% and represents the climate type of the 12 cities.

Keywords

• iran climate
• unep index
• continental coefficient
• climatic parameter
• climate coding