Köppen-Geiger climate classification of Iran and investigation of its changes during 20th century


Assistant Professor, Soil Conservation and Watershed Management Research Institute (SCWMRI), Agricultural Research, Education and Extension Organization (AREO), Tehran, Iran


Climate classification has a long history dating back to the ancient Greek scientists and philosophers, but the first quantitative classification of world climates was presented by the German scientist Wladimir Köppen (1846–1940) in 1900 (Kottek et al, 2006). Being trained as a plant physiologist and realizing that plants are indicators for many climatic elements; Köppen (1900) established a climate classification system which uses monthly temperature and precipitation to define boundaries of different climate types around the world, i.e., linking climate and natural vegetation. This system has been further developed (e.g. Köppen and Geiger, 1930; Stern et al., 2000) and widely used by geographers and climatologists around the world. Although there have been many efforts to find alternative ways to classify the climate, the Köppen system remains one of the most widely used climate classification systems. In this research, monthly precipitation and temperature of 155 Iranian synoptic weather stations with relatively regular distribution over the country were used to provide an updated map of climate classification for Iran which is one of the largest countries with diverse climates in the world. Missing values of the used data were estimated and replaced using inverse distance weighed method. Monthly averages of precipitation and temperature for the considered time period (1990-2014) were then interpolated at a network of grids with 0.1 spatial resolutions using ordinary Kriging method. Subsequently, the climate types of the used stations as well as of the predefined grid points were determined using Köppen-Geiger classification method (Kottek et al, 2006; Chen and Chen, 2013). Additionally, following Rubel and Kottek (2010), monthly mean temperature of the Climatic Research Unit (CRU) of the University of East Anglia and monthly total precipitation of the Global Precipitation Climatology Centre (GPCC), both covering 1901-2014 time period and having 0.5 spatial resolution were used for computing Köppen-Geiger climate classification for different time sections of present time, in order to examine if the Iranian climate types have experienced any shift due to global climate change.
Based on the observational data for 1990-2014 time section Iran composes of 9 climate types out of 31 possible Köppen-Geiger climate types. Most parts of central, eastern and southern Iran is characterized with BWh and BWk climate types. The coastal areas of the Caspian Sea and most parts of mountainous areas of Zagros and Alborz in west and north of Iran have moderate climate type (Csa). However, the eastern slope of Zagros and southern slope of Alborz that are connected to the central arid and semi-arid climate of central Iran are distinguished with BSk climate. The southern parts of Zagros region is mostly dominated by BSh climate. Dsa and Dsb climate types are found in some parts of mountainous areas of Zagros and Alborz, while Csb and Cfa are the localized climate types that can be found in coastal areas of the Caspian Sea. Using CRU and GPCC datasets for 1951-2000 time section the same climate types were found for Iran although the sources of the data and its spatial and temporal resolution differs from that of observational data. The identified climate types in this study using observational data are in agreement with those of Kottek et al. (2006) and Chen and Chen (2013) for Iran. The identified climate types for different time sections of 1901-1925, 1926-1950, 1951-1975, 1976-2000 and 1990-2014 revealed that some Iranian climate types were not stable during these five time periods. Comparison of climate classification using observational data for 1990-2014 with those of gridded datasets for 1901-1925, 1926-1950, 1951-1975, 1976-2000 and 1990-2014 revealed that Dfa and Dfb climate types have disappeared from Iran in the map of 1990-2014 climate classification, suggesting that the number of Iranian climate types have decreased from 11 to 9 in most recent years. It was found that the area of BWk climate in central-eastern Iran is continuously retreated by time and it replaced by BWh climate. The Ds climate types were found to be very vulnerable to change and shift. It was also found that the Dsb climate type tends to shift into Dsa climate types in recent years. Most importantly, it was observed that the Ds climate types in western Iran tend to be replaced by Csa climate type. However, the obvious shift from Ds or Csa climate types into BSk climate type is observed in northwestern Iran. This result indicates a rapid and widespread desertification in northwestern Iran due to global climate change.


Main Subjects

خلیلی، ع.، حجام، س. و ایران‌نژاد، پ.، 1370، تقسیمات آب‌وهوائی ایران، انتشارات وزارت نیرو، طرح جامع آب کشور (جاماب)، 259 صفحه و یک نقشه با مقیاس یک میلیونیم.
عدل، ا. ح.، 1339، آب‌وهوای ایران، انتشارات دانشگاه تهران.
گنجی، م. ح.، 1334، تقسیمات اقلیمی ایران، نشریه دانشکده ادبیات دانشگاه تهران، سال سوم، شماره 1.
گنجی، م. ح.، 1353، میزان باران و منابع آب ایران، 32 مقاله جغرافیایی، انتشارات موسسه جغرافیایی و کارتوگرافی سحاب، صص 258-276.
مسعودیان، س. ا. و کاویانی، م. ر.، 1387، اقلیم‌شناسی ایران، انتشارات دانشگاه اصفهان، 179 صفحه.
میری، م.، رضیئی، ط. و رحیمی، م.، 1395، ارزیابی و مقایسه با داده های GPCC و TRMM آماری داده های بارش مشاهد های در ایران، مجله فیزیک زمین و فضا، دوره 42، شماره 3، صفحه 657-672.
Chan, D., Wu, Q., Jiang, G. and Dai, X., 2016, Projected Shifts in Köppen Climate Zones over China and Their Temporal Evolution in CMIP5 Multi-Model Simulations, Advances in Atmospheric Sciences, 33, 283–293.
Chen, D. and Chen, H. W., 2013, Using the Köppen classification to quantify climate variation and change: An example for 1901–2010, Environmental Development, 6, 69-79.
De Castro, M., Gallardo, C., Jylha, K. and Tuomenvirta, H., 2007, The use of a climate-type classification for assessing climate change effects in Europe from an ensemble of nine regional climate models, Climate Change, 81, 329–341.
Diaz, H. F. and Eischeid, J. K., 2007, Disappearing alpine tundra Köppen climatic type in the western United States, Geophysical Research Letters 34, L18707, http://dx.doi.org/10.1029/2007GL031253.
Djavadi, C., 1966, Les climats de l'Iran, Monographies de la météorologie nationale, France, No. 54, 103 pages.
FAO–SDRN, 1997, Koeppen’s climate classification map 1997. http://www.fao.org/sd/EIdirect/climate/EIsp0002.htm (access February, 1st 2006).
Fraedrich, K., Gerstengarbe, F. W. and Werner, P. C., 2001, Climate shifts during the last century, Climatic Change, 50, 405–417.
Guetter, N. E. and Kutzbach, J. E., 1990, A modified Koeppen classification applied to model simulations of glacial and interglacial climates, Climatic Change, 16, 193–215.
Kim, H. J., Wang, B., Ding, Q. ‌and Chung, I. U., 2008, Changes in arid climate over North China detected by the Köppen climate classification, Journal of Meteorological Society of Japan, 86 (6), 981–990.
Kleidon, A., Fraedrich, K. and Heimann, M., 2000, A green planet versus a desert world: Estimating the maximum effect of vegetation on the land surface climate, Climate Change, 44, 471–493.
Koeppen, W., 1931, Grundriss der Klimakunde, Walter de Gruyter & Co: Berlin.
Köppen, W., 1900, Versucheiner Klassifikation der Klimate, vorzugsweise nach ihren Beziehungen zur Pflanzenwelt, Geographische Zeitschrift, 6, 657–679.
Köppen, W., 1936, Das geographische System der Klimate. In: Köppen W, Geiger R (eds) Handbuch der Klimatologie. Gebrüder Borntraeger, Berlin, p 1−44.
Köppen, W. and Geiger, R., 1930, Handbuch der Klimatologie. Gebrueder Borntraeger, Berlin.
Kottek, M., Grieser, J., Beck, C., Rudolf, B. and Rubel, F., 2006, World Map of the Köppen–Geiger climate classification updated, Meteorologische Zeitschrift, 15(3), 259–263.
Lohmann, U., Sausen, R., Bengtsson, L., Cubasch, U., Perlwitz, J. and Roeckner, E., 1993, The Köppen climate classification as a diagnostic tool for general circulation models, Climate Res, 3, 177–193.
Peel, M. C., Finlayson, B. L. and McMahon, T. A., 2007, Updated world map of the Köppen-Geiger climate classification, Hydrol. Earth Syst. Sci., 4, 439–473.
Peel, M. C., Mcmahon, T. A., Finlayson, B. L. and Watson, F. G. R., 2001, Identification and explanation of continental differences in the variability of annual runoff, J. Hydrol., 250, 224–240.
Rahimi, J., Ebrahimpour, M. and Khalili, A., 2013, Spatial changes of extended De Martonne climatic zones affected by climate change in Iran, Theor Appl Climatol, 112, 409–418.
Rahimzadeh, F., Asgari, A. and Fattahi, E., 2009, Variability of extreme temperature and precipitation in Iran during recent decades, Int. J. Climatol., 29, 329–343.
Raziei, T., Daryabari, J., Bordi, I. and Pereira, L. S., 2014, Spatial patterns and temporal trends of precipitation in Iran, Theor Appl Climatol, 115, 531–540.
Rubel, F. and Kottek, M., 2010, Observed and projected climate shifts 1901–2100 depicted by world maps of the Koppen- Geiger climate classification, Meteorol. Z., 19, 135–141.
Rudloff, W., 1981, Weltklimate, Naturwissenschaftliche, Rundschau, 34, 443–450.
Soltani, M., Laux, P., Kunstmann, H., Stan, K., Sohrabi, M. M., Molanejad, M., Sabziparvar, A. A., Ranjbar SaadatAbadi, A., Ranjbar, F., Rousta, I., Zawar-Reza, P., Khoshakhlagh, F., Soltanzadeh, I., Babu, C. A., Azizi, G. H. and Martin, M. V, 2015, Assessment of climate variations in temperature and precipitation extreme events over Iran, Theor Appl Climatol, DOI 10.1007/s00704-015-1609-5.
Sparovek, G., De Jong Van Lier, Q. and Dourado Neto, D., 2007, Computer assisted Koeppen climate classification: a case study for Brazil, Int. J. Climatol., 27, 257–266.
Stern, H., de Hoedt, G. and Ernst, J., 2000, Objective classification of Australian climates, Australian Meteorological Magazine, 49, 87–96.
Thornthwaite, C. W., 1948, An approach toward a rational classification of climate. Geographical Review, 38(1), 55–94.
Trewartha, G. T., 1980, An introduction to climate, (5th Edn). McGraw-Hill Book Co., New York, London.
Wang, M. and Overland, J. E., 2004, Detecting Arctic climate change using Köppen climate classification, Climate Change, 67, 43–62.