Trends and changes in air temperature and precipitation over different regions of Iran

Authors

1 Assistant Professor, Space Physics Department, Institute of Geophysics, University of Tehran, Iran

2 Ph.D. Student, Climatology Department, Faculty of Geography and Planning, University of Tabriz, Iran

Abstract

Observations unequivocally show that climate change is happening in most regions of the globe. Warming which has been observed in most regions of the globe, particularly in recent decades, is the best manifestation of the climate change. In contrast to the warming of the most regions of the world, many places across the globe have experienced different changes in the amount and intensity of precipitation, such that under the global warming both increases and decreases of precipitation have been reported. Using meteorological records of fifteen ground stations across Iran for a 63-yr period from 1951 to 2013, trends of the minimum, maximum and daily mean near-surface air temperatures and annual accumulated precipitation are examined. Results indicated that the annual minimum, maximum and daily mean near-surface air temperatures in most regions of Iran have experienced increasing trends. Thus, Iran, like most regions of the world, has been rapidly warming over the past few decades. The observed increasing trend in air temperature is mostly attributed to the increase of the greenhouse gases due to human activities. In most regions of Iran, the increasing trends of the minimum temperature have been greater than those of the maximum temperature, the feature which has been mostly attributed to the urbanization development. Indeed, through blocking the outgoing longwave radiation, the urbanization development has effectively contributed to the more significant increase of the minimum temperature than the maximum. In addition, the urban air pollution decreases the incoming shortwave radiation reaching to the Earth surface; thereby partly contributes to the less increase of the maximum temperature compared to the minimum. As a result, a decreasing trend in the diurnal temperature range (the difference between the daytime maximum and nighttime minimum temperatures) is identified. Temperatures in most regions of Iran have experienced a changing point either in 1980s or 1990s, such that the mean temperature of the all regions during the period after the changing point was approximately 1.2 ˚C greater  than the mean temperature during the period before the changing point. Under the warming, most regions of Iran have experienced decreasing trends in the annual accumulated precipitation, although most of the trends have not been statistically significant. The decrease of precipitation, and  the increase of air temperature imply that Iran has become drier and more vulnerable to drought over the past few decades. The observed decreasing trend in precipitation over Iran is in contrast to the trend of global mean precipitation, for which the increase of precipitation under the global warming has been noted. Indeed, previous studies have indicated that 1K rise in temperature is associated with 2 percent increase in the global mean precipitation. However, the results of the present study are consistent with previous studies conducted over the subtropical regions. In a warmer climate, saturation of the atmosphere takes alonger time, which delays the onset of precipitation. Thus, in the arid and semi-arid regions of Iran with the dominant subtropical climate, more water vapour can be transported to higher latitudes by the general circulation of the atmosphere before precipitation can form. In contrast, previous studies have indicated that precipitation increases in both subpolar and tropical regions. We, therefore, argue that depending on the geographical location, the intensity and frequency of precipitation vary in response to the warming of the climate.

Keywords

Main Subjects

References

صفرراد، ط.، عزیزی، ق.، محمدی، ح. و فرجی سبکبار، ح.، 1394، تغییرپذیری شدت پرفشار سیبری در دورۀ تشدید گرمایش جهانی، جغرافیا و مخاطرات محیطی،
شماره 13، صص 77-94.
عزیزی، ق.، فرجی سبکبار، ح.، عباسپور، ر. ‌ع. و صفرراد، ط.، 1389، مدل تغییرات مکانی بارش در زاگرس میانی، پژوهشهای جغرافیای طبیعی، شماره 72، 35-51.
گلزاری پرتو، ل.، 1394، شبیه‌سازی اثر خشک شدن دریاچه ارومیه بر بارش منطقه شمال‌غرب ایران، جغرافیا و مخاطرات محیطی، شماره 14، صص 137-147.
محمدی، ب.، 1390، تحلیل روند بارش سالانه ایران، مجله جغرافیا و برنامه ریزی محیطی، شماره 43 (3)، صص 95-106.
مفیدی، ع.، حمیدیان‌پور، م.، سلیقه، م. و علیجانی، ب.، 1392، تعیین زمان آغاز، خاتمه و طول مدت وزش باد سیستان با بهره گیری از روش های تخمین نقطۀ تغییر، جغرافیا و مخاطرات محیطی، شماره 8، صص 87-113.
Alexander, L. V., Zhang, X., Peterson, T. C., Caesar, J., Gleason, B., Tank, A.M.G.K., Haylock, M., Collins, D., Trewin, B., Rahimzadeh, F., Tagipour, A., Kumar, K. R., Revadekar, J., Griffiths, G., Vincent, L., Stephenson, D. B., Burn, J., Aguilar, E., Brunet, M., Taylor, M., New, M., Zhai, P., Rusticucci, M. and Vazquez-Aguirre, J. L., 2006, Global observed changes in daily climate extremes of temperature and precipitation. J Geophys Res 111:D05,109.
Alizadeh-Choobari, O., Ahmadi-Givi, F., Mirzaei, N. and Owlad, E., 2016b, Climate change and anthropogenic impacts on the rapid shrinkage of Lake Urmia. Int J Climatol 36:4276–4286. doi: 10.1002/joc.4630.
Alizadeh-Choobari, O., Ghafarian, P. and Adibi, P., 2016a, Inter-annual variations and trends of the urban warming in Tehran. Atmos Res 170:176–185. doi:10.1016/j.atmosres.2015.12.001.
Alizadeh-Choobari, O. and Najafi, M. S., 2017, Extreme weather events in Iran under a changing climate. Clim Dyn, in press. doi: 10.1007/s00382-017-3602-4.
Buishand, T. A., 1982, Some methods for testing the homogeneity of rainfall records. Journal of Hydrology 58, 11-27.
Cess, R. D., Udelhofen, P. M., 2003, Climate change during 1985-1999: Cloud interactions determined from satellite measurements. Geophys Res Lett 30, 1019. doi: 10. 1029/ 2002GL016128.
Chen, J. L., Wilson, C. R. and Tapley, B. D., 2013, Contribution of ice sheet and mountain glacier melt to recent sea level rise. Nature Geosci 6(7), 549. doi:10.1038/ngeo1829.
Childs, P. P. and Raman, S., 2005, Observations and numerical simulations of urban heat island and sea breeze circulations over New York city. Pure Appl Geophys 162(10), 1955–1980. doi:10.1007/s00024-005-2700-0
Cook, J., Nuccitelli, D., Green, S. A., Richardson, M., Winkler, B., Painting, R., Way, R., Jacobs, P. and Skuce, A., 2013, Quantifying the consensus on anthropogenic global warming in the scientific literature. Environ Res Lett 8(2), 024,024. doi:10.1088/1748-9326/8/2/024024.
Cook, B. I., Puma, M. J. and Krakauer, Y., 2010, Irrigation induced surface cooling in the context of modern and increased greenhouse gas forcing. Clim Dyn 37, 1587-1600. doi: 10. 1007/ s00382- 010-0932-x.
Coumou, D. and Rahmstorf, S., 2012, A decade of weather extremes. Nature Clim Change 2(7), 491. doi:10.1038/nclimate1452.
Evans, J. P., 2009, 21st century climate change in the Middle East. Climatic Change 92(3), 417–432. doi:10.1007/s10584-008-9438-5.
Hulme, M., 2014, Attributing weather extremes to ’climate change’: A review. Prog Phys Geogr 38(4):499–511.
doi:10.1177/0309133314538644.
Hanna, E., Huybrechts, P., Steffen, K., Cappelen, J., Huff, R., Shuman, C., Irvine-Fynn, T., Wise, S. and Griffiths, M., 2008, Increased runoff from melt from the Greenland ice sheet: A response to global warming. J Clim 21(2), 331–341.
Huber, M. and Knutti, R., 2012, Anthropogenic and natural 459 warming inferred from changes in Earth’s energy balance. Nature Geosci 5(1), 31.
IPCC, 2013, Climate change 2013, The physical science basis exit EPA disclaimer. Contribution of working groups I, II and III to the fifth assessment report of the Intergovernmental Panel on Climate Change, [Stocker, T. F., Qin, D., Plattner, G.-K., Tignor, M., Allen, S. K., Boschung, J., Nauels, A., Xia, Y., Bex, V. and Midgley, P. M., (eds.)]. Cambridge Univ. Press, Cambridge, U. K. and New York, NY, USA.
Kalnay, E., Cai, M., Li, H. and Tobin, J., 2006, Estimation of the impact of land surface forcings on temperature trends in eastern United States. J Geophys Res 111:D06,106. doi: 10.1029/2005JD006555.
Karl, T. R., Jones, P. D., Knight, R. W. and Kukla, G., 1993, A new perspective on recent global warming: Asymmetric trends of daily maximum and minimum temperature. Bull Amer Meteor Soc 74(6), 1007–1023.
Knowles, N., Dettinger, M. D. and Cayan, D. R., 2006, Trends in snowfall versus rainfall in the western United States. J Clim 19(18), 4545–4559.
Kueppers, L. M., Snyder, M. A. and Sloan, L. C., 2007, Irrigation cooling effect: Regional climate forcing by land-use change. Geophys Res Lett 34: L03703. doi: 10. 1029/ 2006GL028679.
Kusaka, H. and Kimura, F., 2004, Coupling a single-layer urban canopy model with a simple atmospheric model: impact on urban heat island simulation for an idealized case. J Meteor Soc Japan 82, 67–80.
Lucas, C., Timbal, B. and Nguyen, H., 2014, The expanding tropics: a critical assessment of the observational and modeling studies. WIREs: Climate Change 5(1), 89–112.
Philipona, R. and Dürr, B., 2004, Greenhouse forcing outweighs decreasing solar radiation driving rapid temperature rise over land. Geophys Res Lett 31, L22,208.
Reyes-Fox, M., Steltzer, H., Trlica, M. J., McMaster, G. S., Andales, A. A., LeCain, D. R. and Morgan, J. A., 2014, Elevated CO2 further lengthens growing season under warming conditions. Nature 510(7504), 259–262.
Rossow, W. B. and Duenãs, E. N., 2004, The international satellite cloud climatology project (ISCCP) web site: An online resource for research. Bull Amer Meteor Soc 85(2), 167–172.
Saeidabadi, R., Najafi, M. S., Roshan, G. R., Fitchett, M. J. and Abkharabat, Sh., 2016, Modelling Spatial, Altitudinal and Temporal Variability of Annual Precipitation in Mountainous Regions: The Case of the Middle Zagros, Iran, Asia-Pac. J. Atmos. Sci., 52(5), 437-449.
Stephens, G. L. and Ellis, T. D., 2008, Controls of global-mean precipitation increases in global warming GCM experiments. J Clim 21(23), 6141–6155. doi: 10. 1175/ 2008JCLI2144.1.
Stone R. S., Dutton E. G. , Harris J. M. and Longenecker D., 2002, Earlier spring snowmelt in northern Alaska as an indicator of climate change. J Geophys Res 107(D10):4089. doi: 10.1029/2000JD000286.
Sun, B., 2003, Cloudiness over the contiguous United States: Contemporary changes observed using ground-based and ISCCP D2 data. Geophys Res Lett 30(2), 1053.
Trenberth, K., Jones, P., Ambenje, P., Bojariu, R., Easterling, D., Klein Tank, A., Parker, D., Rahimzadeh, F., Renwick, J., Rusticucci, M. B. S. and Zhai, P., 2007, Observations: Surface and Atmospheric Climate Change. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K.B., Tignor, M. and Miller, H. L., (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
Journal of the Earth and Space Physics
Volume 43, Issue 3
October 2017
Pages 569-584

Files

Share

How to cite

Statistics