Detection and regional analysis of heatwave characteristics in İstanbul

Merve Yılmaz*, Yiğitalp Kara, Hazal Cansu Çulpan, Günay Can, Hüseyin Toros

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Understanding heatwave characteristics is crucial for mitigating their adverse effects in İstanbul, a densely populated metropolis characterized by a high concentration of buildings, concrete structures, and limited green spaces. This study aims to develop a methodology for defining heatwaves by identifying appropriate thermal indicators. Utilizing the Distributed Lag Nonlinear Model (DLNM), this research investigates the complex and delayed effects of daily mean, maximum, and minimum temperatures, along with seven thermal indices, on daily mortality rates during the summer months of 2013–2017, leveraging the DLNM approach's flexibility in modeling the nonlinear exposure-response relationships. Heatwaves are defined based on the Minimum Mortality Temperature (MMT) and 90th percentile thresholds, and heatwave maps are constructed by their frequency, intensity, duration, and cumulative intensity characteristics. PETmean emerges as the optimal thermal index, exhibiting the lowest Akaike's Information Criteria (AIC: 3553) and estimates relative risk (RR) of 1.080 (95% CI: 1.051–1.110) for a 1°C increase above the 90th percentile. Additionally, Tmean, Tmax, PETmax, and Tmrtmean indices demonstrate favorable characteristics, with low AIC values and high RR estimates. Notably, heatwaves are intense and frequent in Çatalca despite low urban land use and abundant forests, but their duration was short due to fast adaptation capability of the region.

Original languageEnglish
Article number104789
JournalSustainable Cities and Society
Publication statusPublished - Oct 2023

Bibliographical note

Publisher Copyright:
© 2023 Elsevier Ltd


This study has been supported by The Scientific and Technological Research Council of Türkiye (TÜBİTAK - Project No:122Y059). This study has been supported by The Scientific and Technological Research Council of Türkiye (TÜBİTAK - Project No:122Y059). The authors thank Turkish State Meteorological Service (TSMS) for providing meteorological data, the İstanbul Provincial Directorate of Health for mortality data, and Prof. Dr. Andreas Matzarakis for sharing RayMan Pro software. Also, we are grateful for the constructive comments of Prof. Dr. Mete Tayanç and Dr. Ceyhan Kahya.

FundersFunder number
Turkish State Meteorological Service
Türkiye Bilimsel ve Teknolojik Araştırma Kurumu:122Y059


    • Exposure-response function
    • Heat stress threshold
    • Heatwave
    • Minimum mortality temperature
    • Sustainability
    • Thermal index


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