Abstract
This study reveals the dynamics in the number and intensity of heat waves in Bulgaria in the late 20th and early twenty-first century, as well as their impact on forest fires in the beginning of this century. Statistical methods such as linear regression and Spearman’s correlation were the main tools of this study. Multiple linear regression models were used in order to reveal the complex influence of heat wave characteristics on forest fires in Bulgaria. Over the last four decades, there has been a statistically significant trend of increasing number of days belonging to heat waves. There is no significant trend (except in southwestern Bulgaria) in the average maximum temperatures of heat waves in the period 1979–2021. This is due to a change in the atmospheric circulation over Bulgaria in the twenty-first century toward increased transport of air masses from northeast in summer. The heat waves have a significant impact on the forest fires in Bulgaria in summer. In general, more, longer and having higher air temperatures heat waves provide more favorable conditions for the occurrence and development of forest fires. The results of this study can serve to build on the existing methodology for determining the risk of forest fires in the territory of Bulgaria, including factors such as the total duration and intensity of heat waves.
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Funding
This work has been carried out in the framework of the National Science Program “Environmental Protection and Reduction of Risks of Adverse Events and Natural Disasters,” approved by the Resolution of the Council of Ministers № 577/17.08.2018 and supported by the Ministry of Education and Science (MES) of Bulgaria (Agreement № Д01-363/17.12.2020).
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All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Peter Nojarov and Mariyana Nikolova. The first draft of the manuscript was written by Peter Nojarov and Mariyana Nikolova. All authors read and approved the final manuscript.
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Nojarov, P., Nikolova, M. Heat waves and forest fires in Bulgaria. Nat Hazards 114, 1879–1899 (2022). https://doi.org/10.1007/s11069-022-05451-3
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DOI: https://doi.org/10.1007/s11069-022-05451-3