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An International Year of Planet Earth-2008 Initiative

Current Issue Technical

Year 2017

Volume X

Projections of Temperature, Precipitation and Snow Cover Area over Iran During the 21st Century
Mohammad Zarenistanak

 In this paper, results of the projections of temperature, precipitation and snow cover area for the 21st century over Iran is presented. The future projections were carried out at Centre National de Recherch√© Meteorologiques (CNRM), European Center Hamburg Model (ECHAM), and United Kingdom Meteorological Office (UKMOC) for contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4), underB1 and A1B emission scenarios. The analysis of temperature projections revealed that temperature may increase between 1.27 to 5.380 C by the end of the twenty-first century. Summer temperature may increase with higher rates than other season. Precipitation projection shows that precipitation will decrease annually, through winter, spring and summer in Iran by 2100. Total annual precipitation may decrease by -9.92% under B1 scenario and -8.18% under A1B scenario. Autumn precipitation may increase at the end of this century under B1 and A1B emission scenarios. Snow cover projection was conducted relative to snow cover-observed period which included the months of December, January, February, March and April. The result of snow cover projection showed that snow cover area might decrease as indicated by CNRM, ECHAM, and UKMOC models under B1 and A1B emission scenarios by the end of the 21st century. On average, snow cover area may decrease by -224040 and -242883 km2 under B1 and A1B scenarios compared to 1981-2000. Spatial variation, annual temperature and precipitation between 2081-2100 and 1981-2000 over Iran show that temperature may increase more in central and west parts of Iran and various patterns of precipitation will not be uniform across the country. Spatial variation of snow cover area during snow cover-observed period shows that the northern half of the country will witness snow coverage in the late current century while the southern half will face no snow cover.

Keywords: Projection; scenarios; temperature; precipitation; snow cover; Iran