Identification and Analysis of Heatwave Characteristics in Iran Based on Multiple Indices

Shakiba, Alireza; Esfandiari, Neda; Mirbagheri, Babak; Allahgholipour, Ehsan

doi:10.22111/jneh.2025.52604.2125

Identification and Analysis of Heatwave Characteristics in Iran Based on Multiple Indices

Articles in Press

Document Type : Research Article

Authors

¹ Associate Professor, Center for Remote Sensing and GIS Research, Shahid Beheshti University, Tehran, Iran

² Postdoc Researcher, Center for Remote Sensing and GIS Research, Shahid Beheshti University, Tehran, Iran

³ Assistant Professor, Center for Remote Sensing and GIS Research, Shahid Beheshti University, Tehran, Iran

⁴ MSc. of GIS, Center for Remote Sensing and GIS Research, Shahid Beheshti University, Tehran, Iran

10.22111/jneh.2025.52604.2125

Abstract

Heatwaves are among the most critical climate-related hazards, posing serious risks to human societies and ecosystems. The accelerating pace of global warming highlights the need for detailed investigations of this phenomenon. In this study, daily maximum and minimum temperature data for 30 years (1995–2024) were used to identify local heatwave thresholds based on the 90th percentile and probability density functions. Five major heatwave characteristics: number of events, number of heatwave days, magnitude, amplitude, and longest duration were extracted across Iran. Their spatial distribution and hotspot regions were identified, and temporal trends were assessed using the Mann–Kendall test and Sen’s slope estimator. Results show that, in addition to arid and southeastern regions (e.g., Lut Desert, Central Plateau, Southern Baluchestan, Hamun basins), high-altitude areas of the Zagros Mountains—particularly the Tashk–Bakhtegan basin—are highly exposed in terms of heatwave frequency and duration. In the lowland plains of the southwest and southeast (e.g., Khuzestan, Lut Desert, Hamun, Baluchestan), heatwave intensity has in some years exceeded 50 °C (maximum) and 40 °C (minimum). Trend analysis revealed statistically significant increases in all heatwave characteristics, especially in the number of events and days, with average slopes of ~0.24 events and 1.2 days per year across most regions. While northern and southern coastal areas (e.g., Persian Gulf coast) have remained relatively unaffected by persistent daytime heatwaves, nighttime events show a clear increasing trend. Moreover, the highest long-term averages for all characteristics occurred during the last eight years of the study period, particularly in 2024.

Keywords

Main Subjects

Environmental Hazards

References

References [in Persian]

Esmaeili, H., Roshani, A. and Parak, F. (2018). Trend analysis of climate compound extreme indices in IRAN. Journal of Meteorology and Atmospheric Science, 1(2), 97-113. [in Persian]

Esmaeil Negad, M., Khosravei, M., Aliganei, B. and Masaoodian, S. (2013). Identifying Heat Waves of Iran. Geography and Development, 11(33), 39-5. [in Persian]

Alavinia, S. H. (2022). Analysis of Extreme Temperature Change Trend under Future Scenarios to Assess Climate Fluctuations (Case Study: Sanandaj and Saghez Synoptic Stations). Journal of Arid Regions Geographic Studies, 11(41), 1-16. [in Persian]

bijandi, M., daryabari, S. J., Ranjbar, A. and Arbabi Sabzevari, A. (2022). Extreme events of cold and heat waves in the northeastern regions of Iran during the period 2001-2020. Journal of Climate Research, 1401(50), 41-60. [in Persian]

Dargahian, F., Heidarnejad, S. and Razavizadeh, S. (2021). Investigating the trend of changes in the heat wave properties related to climate change in arid regions (Case Study: Yazd City). Iranian Journal of Range and Desert Research, 28(3), 564-577. [in Persian]

Doostkamian, M., Haghighi, E. and Bourbouri, R. (2017). Analyzing and Identifying Regional Changes of Hot and Cold Zones in Iran in indifferent Periods. Journal of Geography and Environmental Hazards, 6(2), 141-162. [in Persian]

jahanbakhsh asl, S., ghavidel, F. and ashjaei, M. (2015). Recognition, Classification and synoptical Analysis of Heat waves decreasing human hazards in the North West of Iran. Environmental Management Hazards, 2(4), 377-391. [in Persian]

Ghasemifar, E. and Naserpour, S. (2017). Synoptic analysis of heat and cold waves over the southern coast of the Caspian Sea. Scientific- Research Quarterly of Geographical Data (SEPEHR), 26(103), 137-146. [in Persian]

Karampoor, M., Rafiee, J. and Jafari, A. (2017). Identification and Analysis of Synoptic Heat Waves in West of Iran (Case Study: Ilam, Khouzestan, Lorestan, Kermanshah). Environmental Management Hazards, 4(3), 263-279. [in Persian]

Hamidianpour, M., Nazaripour, H., Khazaie Fizabad, E., Farzane, M. and Firoze, S. (2023). Determining the change point of temperature thresholds of heat and cold waves in Iran during 1966-2018. Journal of Natural Environmental Hazards, 12(37), 133-150. [in Persian]

Rezaei, F., Ahmadi, M. and Shakiba, A. (2019). Simulation of temperature threshold heat waves during warm spells in Iran based on scenarios RCP (2016-2045). Research in Earth Sciences, 10(3), 231-247. [in Persian]

Zarrin, A. and Dadashi-Roudbari, A. (2021). Projected changes in temperature over Iran by 2040 based on the CMIP6 multi-model ensemble. Physical Geography Research, 53(1), 75-90. [in Persian]

References [in English]

Abbasnia, M. (2019). Climatic characteristics of heat waves under climate change: a case study of mid-latitudes, Iran. Environment, Development and Sustainability, 21(2), 637–656.https://doi.org/10.1007/s10668-017-0052-4

Abbasnia, M., Tavousi, A., & Khosravi, M. (2016). Identification and analysis of heat waves in Iran during 1981–2010: Spatial and temporal variations. Journal of Spatial Analysis & Environmental Hazards, 13, 11–23.

Ansari, A. , Mahmoudi, P. , & Nazaripour, H. (2024). Observed changes in the characteristics of heat waves in hot and dry regions of Iran. Idojaras – Quarterly Journal of the Hungarian Meteorological Service, 128(4), 473–496.

Barton, L., & Greig, D. (2019). Using dynamic heat thresholds to assess heatwave events in the context of climate change. Environmental Research Letters, 14(10), 104018.https://doi.org/10.1088/1748-9326/ab3c74

Barreca, A., Deschênes, O., Greenstone, M., & Shapiro, J. (2016). The effect of absolute versus relative temperature on health and the environment: Evidence from Italy, 2001–2015. Environmental Research Letters, 11(5), 054001.

Beyraghdar Kashkooli, O., Karimian, S., & Modarres, R. (2022). Spatiotemporal variability of the Persian Gulf and Oman Sea marine heatwaves during 1982-2020. Marine Pollution Bulletin, 184, 114174.https://doi.org/10.1016/j. marpolbul. 2022.114174

Bonshoms, M., Ubeda, J., Liguori, G. et al. (2022). Validation of ERA5-Land temperature and relative humidity on four Peruvian glaciers using on-glacier observations. J. Mt. Sci. 19, 1849–1873. https://doi.org/10.1007/s11629-022-7388-4

Climate Central. (2024, August 7). Analysis: Climate change is increasing the danger of nighttime temperatures across the globe. Climate Central.

De Polt, K., et al. (2023). Quantifying the impact of relevant heatwave durations. Environmental Research Letters, 18(10), 104005.

Fallah Ghalhari, G., Farhang Dehghan, S., Akhlaghi Pirposhteh, E., & Asghari, M. (2021). Trend analysis and temporal and spatial distribution of wet bulb globe temperature as a heat stress index in Iran during the summer season over 30 years. Journal of Environmental Health and Sustainable Development, 6(4), 1476–1493.https://doi.org/10.18502/jehsd. v6i4.8153

Fatahian, M., Hejazizadeh, Z., Karbalaee, A. R., Shahidinia, H., & Wang, J. (2025). Spatio Temporal Analysis of Changes in the Iranian Summer Subtropical High Pressure System from a Climate Change Perspective. Atmosphere, 16(3), 273.https://doi.org/10.3390/atmos16030273

Gao, J. , et al. (2015). Impact of extreme high temperature on mortality and regional level definition of heat wave: a multi-city study in China. Science of the Total Environment, 505, 535–544.

Hanna, E. G. , Kjellstrom, T. , Bennett, C. , & Dear, K. (2010). Climate Change and Rising Heat: Population Health Implications for Working People in Australia. Asia Pacific Journal of Public Health, 23(2_suppl), 14S-26S. https://doi.org/10.1177/1010539510391457

Hirsch, A. L., et al. (2022). Changes in land–atmosphere coupling increase compound drought and heatwave risk. Nature Communications, 13, Article 2380.https://doi.org/10.1038/s41467-022-00325-8

Intergovernmental Panel on Climate Change (2012), Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation. A Special Report of Working Groups I and II of the Intergovernmental Panel on Climate Change, edited by C. B. Field et al., 52 pp., Cambridge Univ. Press, Cambridge, U.K., and New York.

Jangi, M. R., Zarrin, A., Mofidi, A., & Dadashi-Roudbari, A. (2024). Intensifying heatwave trends in Iran based on observational data using the excess heat factor (EHF). Natural Hazards, 120(2), 2073-2090.

Joyce, P.W.S., Tong, C.B., Yip, Y.L. et al. Marine heatwaves as drivers of biological and ecological change: implications of current research patterns and future opportunities. Mar Biol 171, 20 (2024). https://doi.org/10.1007/s00227-023-04340-y

Kamangar, M., Ahmadi, M., Rabiei-Dastjerdi, H., & Hazbavi, Z. (2025). Ensemble modeling of extreme seasonal temperature trends in Iran under socio‑economic scenarios. Natural Hazards, 121, 1265–1288.

Kodra, E., & Ganguly, A. (2014). Asymmetry of projected increases in extreme temperature distributions. Scientific Reports, 4, 5884.https://doi.org/10.1038/srep05884

Meehl, G. A. , Tebaldi, C. , Tilmes, S. , Lamarque, J. -F. , Bates, S. , Pendergrass, A. , & Lombardozzi, D. (2018). Future heat waves and surface ozone. Environmental Research Letters, 13(6), 64004.https://doi.org/10.1088/1748-9326/aabcdc

Mojarrad, F., Masoompour, J., & Rostami, T. (2015). Statistical–Synoptic Analysis of Heat Waves above 40°C in the West of Iran. Geography and Environmental Hazards, 13, 11–23.

Muñoz Sabater, J. , Dutra, E. , Agustí Panareda, A. , Albergel, C. , Arduini, G. , Balsamo, G. , … Thépaut, J. N. (2021). ERA5 Land: a state-of-the-art global reanalysis dataset for land applications. Earth System Science Data, 13(9), 4349–4383.

Müller, V., et al. (2024). Evening humid heat maxima near the southern Persian/Arabian Gulf. Communications Earth & Environment.

National Oceanic and Atmospheric Administration (NOAA). (2023). Thermal Properties of Water and Coastal Temperature Moderation. NOAA JetStream.

Nuttall, J. G. , O’Leary, G. J. , Khimashia, N. , Asseng, S. , Fitzgerald, G. , & Norton, R. (2012). ‘Haying-off’ in wheat is predicted to increase under a future climate in south-eastern Australia. Crop and Pasture Science, 63(7), 593–605.

Oke, T. R. (1987). Boundary Layer Climates (Chapter on Coastal Climates). Routledge.

Orlov, A. , Sillmann, J. , Aaheim, A. , Aunan, K. , & de Bruin, K. (2019). Economic Losses of Heat-Induced Reductions in Outdoor Worker Productivity: a Case Study of Europe. Economics of Disasters and Climate Change, 3(3), 191–211.

Perera, A. T. D., Nik, V. M., Chen, D., Scartezzini, J. -L., & Hong, T. (2020). Quantifying the impacts of climate change and extreme climate events on energy systems. Nature Energy, 5(2), 150–159.https://doi.org/10.1038/s41560-020-0558-0

Perkins, S. E. (2015). A review on the scientific understanding of heatwaves—Their measurement, driving mechanisms, and changes at the global scale. Atmospheric Research, 164–165, 242–267.https://doi.org/10.1016/j. atmosres. 2015.05.014

Perkins, S. E., & Alexander, L. V. (2013). On the Measurement of Heat Waves. Journal of Climate, 26(13), 4500–4517.

Poulos, G., & Zhong, S. (2008). An Observational History of Small-Scale Katabatic Winds in Mid-Latitudes. Geography Compass, 2, 1798–1821.https://doi.org/10.1111/j. 1749-8198.2008.00166. x

Raei, E. , Nikoo, M. , AghaKouchak, A. , & GHWR. (2018). GHWR, a multi-method global heatwave and warm-spell record and toolbox. Scientific Data, 5, 180206.https://doi.org/10.1038/sdata. 2018.206

Ren, Y. , Liu, J. , Zhang, T. , Shalamzari, M. J. , Arshad, A. , Liu, T. , Willems, P. , Gao, H. , Tao, H. , & Wang, T. (2023). Identification and Analysis of Heatwave Events Considering Temporal Continuity and Spatial Dynamics. Remote Sensing, 15(5), 1369.https://doi.org/10.3390/rs15051369

Seneviratne, S. I. , Donat, M. G. , & Chéruy, F. (2013). A review of the global impacts of extreme heat events and the implications for climate change adaptation. Nature Climate Change, 3(8), 559–563.https://doi.org/10.1038/nclimate1857

Sharifi, M. , & Ehteram, N. (2016). Spatial-temporal analysis of heat waves in Iran over the last three decades (1981–2010). Natural Environment Change, 2(1), 29–38.

Smith, J., & Zhang, L. (2018). Analysis of temperature extremes using the probability density function (PDF) approach in climate studies. Journal of Climate Research, 34(2), 101-113.https://doi.org/10.1002/jcr. 2345

Stefanon, M., D’Andrea, F., & Drobinski, P. (2012). Heatwave classification over Europe and the Mediterranean region. Environmental Research Letters, 7(1), 014023.https://doi.org/10.1088/1748-9326/7/1/014023

Sutanto, S.J., Zarzoza Mora, S.B., Supit, I. et al. Compound and cascading droughts and heatwaves decrease maize yields by nearly half in Sinaloa, Mexico. npj Nat. Hazards 1, 26 (2024). https://doi.org/10.1038/s44304-024-00026-7

Velikou, K., Lazoglou, G., Tolika, K., & Anagnostopoulou, C. (2022). Reliability of the ERA5 in Replicating Mean and Extreme Temperatures across Europe. Water, 14(4), 543.https://doi.org/10.3390/w14040543

Vogel, M. M. , Zscheischler, J. , Fischer, E. M. , & Seneviratne, S. I. (2020). Development of Future Heatwaves for Different Hazard Thresholds. Journal of Geophysical Research: Atmospheres, 125(9), e2019JD032070.https://doi.org/10.1029/2019JD032070

Wang, Y., & Liu, J. (2024). Impacts of Massive Topographies on Heat Waves in Global Drylands. Geophysical Research Letters, 51(8), e2024GL109979.

Wu, S., Luo, M., Zhao, R., et al. (2023). Local mechanisms for global daytime, nighttime, and compound heatwaves. npj Clim Atmos Sci, 6, 36.https://doi.org/10.1038/s41612-023-00365-8

Yousefi-Kebriya, A., Nadi, M., Afaridegan, E., et al. (2025). Wetland shrinking and dust pollution in Khuzestan, Iran: insights from Sentinel-5 and MODIS satellites. Scientific Reports, 15, 13626.https://doi.org/10.1038/s41598-025-96935-2

Zhai, J. , Xue, X. , Li, W. , et al. (2024). Heatwave magnitude quantization and impact factors analysis over the Tibetan Plateau. npj Climate and Atmospheric Science, 7, Article 85.

Zhao, M., Lee, J. K. W., Kjellstrom, T., & Cai, W. (2021). Assessment of the economic impact of heat-related labor productivity loss: a systematic review. Climatic Change, 167(1), 22. https://doi.org/10.1007/s10584-021-03160-7.