Adaptive Evaluation of SPI, RDI, and SPEI indices in Analyzing the Trend of Intensity, Duration, and Frequency of Drought in Arid and Semi-Arid Regions of Iran

Document Type : Research Paper


1 Assistant Professor, Department of Natural Resource Engineering, University of Hormozgan, Bandar Abass, Iran

2 M.Sc. Graduate of Natural Resource Engineering, Department of Natural Resource Engineering, University of Hormozgan, Bandar Abass, Iran.

3 Associate professor, Department of Agrometeorology, University of Tehran, Karaj, Iran.


Drought is one of the most important weather-induced phenomena which may have severe impacts on different areas, such as agriculture, economy, energy production, and society. From a meteorological point of view, drought can be induced by lack of precipitation, hot temperatures, and enhanced evapotranspiration. The efficiency of the drought monitoring system depends on the index which is selected based on the drought and climate conditions of the region. Precipitation-based drought indices, including the Standardized Precipitation Index (SPI) (McKee et al., 1993), China Z Index (CZI), (Percent of Normal Index) PNI, and others cannot identify the role of the temperature increase in the drought condition and in addressing the consequences of climate change. Recently, two new standardized drought indices have been proposed for drought analysis on multiple time scales: the Reconnaissance Drought Index (RDI) (Tsakiris and Vangelis, 2005) and the Standardized Precipitation Evapotranspiration Index (SPEI) (Vicente Serrano et al., 2011). The objective of this study is to evaluate the characteristics of drought, according to SPEI, SPI, and RDI. In addition, this study evaluates trends in meteorological drought frequency, duration, and severity during the study period through a multi-indicator approach and at low rainfall regions of Iran, providing a complete picture of the areas that suffered frequent and severe droughts in the past periods. Moreover, this might push towards the development of better frameworks for drought assessment, adaptation, and mitigation, in a possibly drier future.


1-    Ahmadi, M., Nosrati, K. and Selki, E., 2013. Drought and its relationship with soil moisture (Case study: Kabodar Abad, Isfahan). Geographiy, 11(38), pp. 77-91.(In Persian).
2-    Banimahd, S.A. and. Khalili. D., 2013. Factors influencing Markov chains predictability characteristics, utilizing SPI, RDI, EDI and SPEI drought indices in different climatic zones. Water Resources Management, 27(11), pp. 3911-3928.
3-    Bazrafshan, A., Chashmbrah, A. and Holisaz, A., 2015. Trend analysis of the pan evaporation in different climates of Hormozgan province. Journal of Conservation and Utilization of Natural Resources, 4(2), pp. 171-176.
4-    Bazrafshan, J. and Hejabi, S., 2016. Drought and methods of monitoring. University of Tehran Press, 234 pages. (In Persian).
5-    Bazrafshan, J., Hejabi, S. and Habibi Nokhandan, M.,  2010. Is the SPI sufficient for monitoring meteorological droughts in extreme costal climates of Iran? Advances in Natural and Applied Sciences, 4(3), PP. 345-351. (In Persian)
6-    Bazrafshan, O., Mahmudzadeh, F., Bazrafshan, J., 2017. Evaluation of temporal trends of the drought indices SPI and SPEI in the Southern Coast of Iran. Desert Management, 4(8), pp. 54-69. (In Persian).
7-    Blenkinsop, S. and Fowler, H.J., 2007. Changes in drought frequency, severity and duration for the British Isles projected by the PRUDENCE regional climate models. Journal of Hydrology, 342, PP. 50-71.
8-    Burke, E.J. and Brown. S.J.,  2008. Evaluating uncertainties in the projection of future drought. Journal of Hydrometeor, 9, PP. 292–299.
9-    Eghtedar Nezhad, M., Bazrafshan, O., Sadeghi Lari, A., 2017. Adaptive Evaluation of SPI, RDI and SDI Indices in Analyzing the Meteorological and Hydrological Drought Characteristics (Case Study: Bam Plain). Water and Soil Science, 26(4.2), pp. 69-81. (In Persian)
10- Kendall, M.G., 1962. Rank correlation methods. The British Psychological Society Publishing, 220P.
11- Kim, D.W., Byun, H.R. and Choi, K.S., 2009. Evaluation, modification, and application of the effective drought index to 200-year drought climatology of Seoul, Korea. Journal of Hydrology, 378, pp. 1–12.
12- Knight, W.E., 1996. A computer method for calculating Kendals Tau with ungrouped data. J Am Stat Assoc 61, pp. 436–439.
13- Mann, H.B., 1945. Nonparametric tests against trend. Econometrica,13(3), pp. 245-259.
14- McKee, T.B., Doesken, N.J. and  Kleist, J., 1993. The relationship of drought frequency and duration to time scales, In Proceedings of the 8th Conference on Applied Climatology, 17(22), pp. 179-17.
15- Mendicino, G., Senatore, A. and Versace, P., 2008. Groundwater resource index (GRI) for drought monitoring and forecasting in a Mediterranean climate. Journal of Hydrology, 357, pp. 282-302.
16- Mishra, A.K. and Desai, V.R., 2005. Drought forecasting using stochastic models. Stochastic Environment Research and Risk Assessment 19, pp. 326-339.
17- Morid, S., Smakhtin, V.U. and Moghadasi, M., 2006. Comparison of seven meteorological indices for drought monitoring in Iran. Int J Climatol, 26, pp. 971–985.
18- Nosrati, K., 2014. Estimation of Standardized Evapotranspiration (SPEI) Index for Dry Dry Identification in Different Climates of Iran. Quarterly Journal of Environmental Science, Volume 12, Issue 4, pp. 63-74. (In Persian)
19- Pashiardis, S. and Michaelides, S., 2008. Implementation of the standardized precipitation index (SPI) and the reconnaissance drought index (RDI) for regional drought assessment: A case study for Cyprus. European Water, 23 (24), pp.57-65.
20- Rahimi, J. Ebrahimpour, M. and Khalili, A., 2013. Spatial changes of Extended De Martonne climatic zones affected by climate change in Iran. Theoretical and Applied Climatology, 112, pp. 409-418.
21- Rezaei, H., Khanmohammadi, N., Montasari, M. and Bahmanesh, J., 2016. Investigating the effect of distribution function and estimation method of potential evapotranspiration in determination of dry matter identification index. Journal of Irrigation Science and Engineering, Volume 40, Special Issue 1/1, pp. 167-183. (In Persian).
22- Sobhani, B., Ghafari Gilandeh, A. and Golghooust, A., 2015. Dry dryness in Ardebil province using the developed SPEI index based on fuzzy logic. Journal of Applied Geosciences Research, Vol. 15, No. 36, pp. 52-71. (In Persian).
23- Taboozadeh, Sh., Zarei, H. and Bazrafshan, A., 2015. Analysis of severity, duration, frequency and extent of meteorological precipitation in Bakhtegan watershed. Journal of Irrigation Science and Engineering, Vol. 38, No. 4, pp. 109-123. (In Persian).
24- Tajbakhsh, S., Eisakhani, N., Fazl Kazemi, A., 2015. Assessment of meteorological drought in Iran using standardized precipitation and evapotranspiration index (SPEI). Journal of the Earth and Space Physics, 41(2), pp. 313-321. (In Persian).
25- Tigkas, D., Vangelis, H. and Tsakiris, G.,  2012. Drought and climate change impact on streamflow in small watersheds. Science of the Total Environment, 1(44), pp. 33-41.
26- Tsakiris, G. and Vangelis, H., 2005. Establishing a drought index incorporating evapotranspiration. European Water, 9(10), pp. 3-11.
27- Tsakiris, G., Pangalou, D. and Vangelis, H., 2007. Regional drought assessment based on the reconnaissance drought index (RDI). Water Resources Management, 21, pp. 821–833.
28-  Visente Serrano, S.M., López-Moreno, J.I., Drummond, A., Gimeno, L., Nieto, R., Morán-Tejeda, E., and  Zabalza, J., 2011. Effects of warming processes on droughts and water resources in the NW Iberian Peninsula, (1930-2006).  Climate Research, 48, pp. 203-212.
29- Visente-Serrano, S.M., Beguería, S. and , López-Moreno, J.I., 2010. A multiscalar drought index sensitive to global warming: the standardized precipitation evapotranspiration index, Journal of Climate, 23(7), pp. 1696-1718.
30- Willmott, C.J., 1981. On the validation of models. Physical Geography, 2, pp. 184–194.
31- Zare Abyaneh, H., Ghabaei Sough, M. and Mosaedi, A., 2015. Drought monitoring based on Standardized Evapotranspiration Index (SPEI) under climate change. Water and Soil Journal, 29 (2), pp. 374-392. (In Persian).
Volume 42, Issue 3
October 2019
Pages 117-131
  • Receive Date: 29 May 2017
  • Revise Date: 28 October 2017
  • Accept Date: 01 November 2017
  • Publish Date: 23 September 2019