Türkiye’de 24 Saatlik METAR Gözlemlerine Dayalı Oraj Günlerinin Klimatolojisi, Eğilimleri ve Atmosferik Çevresel Kontrolleri (2005–2025)

Abstract

Bu çalışma, Türkiye’de 24 saatlik sürekli rasat yapan 23 METAR istasyonuna dayanarak 2005–2025 dönemindeki oraj günü (TSD) klimatolojisini, eğilimlerini ve atmosferik çevresel denetleyicilerini incelemektedir. Saatlik raporlardan türetilen TSD serileri aylık, mevsimlik, yıllık ve gün içi ölçeklerde analiz edilmiştir. Eğilimler Hamed–Rao modifiye Mann–Kendall testi ve Sen eğimi ile değerlendirilmiş; sonuçların sağlamlığı yanlış keşif oranı düzeltmesi ve homojenlik testleriyle sınanmıştır. TSD ile ERA5 ve ERA5-Land’dan türetilen çevresel değişkenler arasındaki ilişkiler Spearman korelasyonu ve çoklu regresyon ile incelenmiştir. Bulgular, Türkiye’de tek tip bir oraj rejimi bulunmadığını göstermektedir. İç ve yüksek sahalarda oraj aktivitesi ilkbahar sonu-yaz başında yoğunlaşırken, güney ve güneybatı kıyılarının bazı kesimlerinde konvektif sezon soğuk yarıyıla uzamaktadır. Oraj gözlemleri ülke genelinde çoğunlukla gündüz gerçekleşmekte, ancak kıyı istasyonlarında gece etkinliği görece daha fazla önem kazanmaktadır. Eğilimler mekânsal olarak heterojendir; çoklu test düzeltmesi sonrasında yıllık ölçekte yalnızca Ankara’daki artış istatistiksel olarak dayanıklı kalmıştır. Çevresel analizler, yıllar arası TSD değişkenliğini açıklamada K-indeksi ile konvektif yağışın CAPE’den daha tutarlı olduğunu, buna karşılık yüzey ısınmasının tek başına gözlenen değişimleri açıklamadığını göstermektedir. Sonuç olarak çalışma, Türkiye’de oraj klimatolojisini yorumlamak için istatistiksel açıdan temkinli ve veri temelli bir çerçeve sunmaktadır.

Keywords

• Oraj günü
• METAR
• Türkiye
• Mann–Kendall
• homojenlik
• ERA5
• konvektif çevre

Ethical Statement

Yazarlar, herhangi bir çıkar çatışması bulunmadığını beyan eder. Bu çalışma için etik kurul izni gerekmemektedir.

Thanks

Yazarlar, bu çalışmada kullanılan METAR arşivine erişim sağladığı için Iowa State University Iowa Environmental Mesonet’e içtenlikle teşekkür eder. Yazarlar ayrıca, ERA5 ve ERA5-Land yeniden analiz veri setlerine açık erişim sağladıkları için Copernicus Climate Change Service ile European Centre for Medium-Range Weather Forecasts’e (ECMWF) teşekkür eder. Bu kaynaklar, bu çalışmada sunulan analizlerin temel gözlemsel ve çevresel veri altyapısını oluşturmuştur.

Climatology, Trends, and Atmospheric Environmental Controls of Thunderstorm Days in Türkiye Based on 24-Hour METAR Observations (2005–2025)

Abstract

his study examines the climatology, trends, and atmospheric environmental controls of thunderstorm days (TSDs) in Türkiye during 2005–2025 using 23 METAR stations with continuous 24-hour observations. TSD series derived from hourly reports were analysed at monthly, seasonal, annual, and diurnal scales. Trends were assessed with the Hamed-Rao modified Mann-Kendall test and Sen’s slope, with false discovery rate correction and homogeneity tests used to evaluate robustness. Relationships between TSD and environmental variables from ERA5 and ERA5-Land were examined using Spearman correlation and multiple regression. Results show that Türkiye does not exhibit a single thunderstorm regime. Inland and high-elevation stations are characterized by a late- spring to early-summer maximum, whereas parts of the southern and southwestern coasts experience a longer convective season extending into the cold half of the year. Thunderstorm observations are predominantly daytime events nationally, but nighttime activity is relatively more important at coastal stations. Trend results are spatially heterogeneous; after multiple-testing correction, only the annual increase at Ankara remains statistically robust. Environmental analyses indicate that the K-index and convective precipitation explain interannual TSD variability more consistently than CAPE, while surface warming alone does not account for observed changes. Overall, the study provides a statistically cautious framework for understanding thunderstorm climatology in Türkiye.

Keywords

• Thunderstorm day
• METAR
• Türkiye
• Mann–Kendall
• homogeneity
• ERA5
• convective environment

Ethical Statement

Confilict of Interest: The authors declare that there is no conf lict of interest. Ethics Committee

Thanks

The authors gratefully acknowledge the Iowa State University Iowa Environmental Mesonet for providing access to the METAR archive used in this study. The authors also thank the Copernicus Climate Change Service and the European Centre for Medium-Range Weather Forecasts (ECMWF) for providing open access to the ERA5 and ERA5-Land reanalysis datasets. These resources constituted the core observational and environmental data foundation of the present analysis.

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