Future Precipitation and Temperature Projections Using CMIP6 Global Climate Models: Application to Diyarbakır

Abstract

Projections of the future evolution of climate-induced natural disasters, together with assessments of their potential impacts, represent a crucial first step in identifying effective mitigation and adaptation strategies. This study projects future precipitation and temperature patterns with the aim of supporting the development of scientifically grounded policies to reduce disaster risks and impacts in the province of Diyarbakır. To this end, 24 distinct Global Climate Models (GCMs) from the Coupled Model Intercomparison Project Phase 6 (CMIP6), which provides higher-resolution simulations and more detailed representations of physical processes, were employed. Past, present, and future precipitation and temperature conditions were simulated using the CMIP6 historical experiment and two Shared Socioeconomic Pathway scenarios (SSP2-4.5 and SSP5-8.5). The CMhyd software package was used to downscale GCM simulations to the station scale and correct systematic biases in model outputs, with the linear scaling method applied for bias correction. The bias-corrected precipitation and temperature series from the CMIP6 historical experiment were validated against observational station data, enabling the identification of the best-performing GCMs. Finally, bias-corrected projections from these models under the mid-forcing SSP2-4.5 and high-forcing SSP5-8.5 scenarios were analyzed to assess prospective climatic changes in Diyarbakır. The findings demonstrate that climate change is projected to persist in Diyarbakır through rising temperatures and declining precipitation, thereby rendering the formulation of regional adaptation strategies indispensable.

Keywords

• Climate change
• CMIP6
• GCM
• CMhyd
• Diyarbakır

CMIP6 Küresel İklim Modelleri ile Gelecek Yağış ve Sıcaklık Tahminleri: Diyarbakır için Bir Uygulama

Abstract

İklim kaynaklı doğal afetlerin gelecekte nasıl değişeceğine ilişkin tahminler ve bu değişimlerin olası etkilerinin ortaya konulması, alınacak önlemlerin belirlenmesinde ilk adımı oluşturmaktadır. Bu çalışma, Diyarbakır ili özelinde afet risklerinin ve etkilerinin azaltılmasına yönelik bilimsel temelli politikaların geliştirilmesine katkı sağlamak amacıyla, gelecekteki yağış ve sıcaklık değerlerinin tahminine odaklanmaktadır. Çalışmada, iklim modellerinin daha yüksek çözünürlükte ve daha ayrıntılı fiziksel süreçlerle çalışmasına imkân tanıyan Birleştirilmiş Model Karşılaştırma Projesi Faz 6 (CMIP6) kapsamında yer alan 24 farklı Küresel İklim Modeli (GCM) kullanılmıştır. Geçmiş, mevcut ve gelecekteki yağış ile sıcaklık değerleri; CMIP6 tarihsel deney senaryosu ve iki farklı Paylaşımlı Sosyoekonomik Rota (SSP2-4.5 ve SSP5-8.5) senaryosu aracılığıyla simüle edilmiştir. GCM’lere ait simülasyonların seçilen istasyona en yakın konuma indirgenmesi ve modelleme kaynaklı yanlılıkların düzeltilmesi için CMhyd yazılımı kullanılmış, yanlılıkların düzeltilmesinde doğrusal ölçeklendirme yöntemi tercih edilmiştir. CMIP6 tarihsel deneyi kapsamındaki yanlılıkları düzeltilmiş yağış ve sıcaklık simülasyonları istasyon verileriyle karşılaştırılarak en iyi performans gösteren GCM’ler belirlenmiştir. Daha sonra bu GCM’lere ait orta etki SSP2-4.5 ve yüksek etki SSP5-8.5 senaryoları kapsamındaki yanlılıkları düzeltilmiş yağış ve sıcaklık projeksiyonları üzerinden Diyarbakır ili ikliminin gelecekte nasıl değişebileceği değerlendirilmiştir. Sonuçlar, iklim değişikliğinin Diyarbakır’da sıcaklıkları artırıp yağışları azaltarak etkilerini sürdüreceğini ve bu çerçevede bölgesel uyum stratejilerinin geliştirilmesinin kaçınılmaz olduğunu ortaya koymaktadır.

Keywords

• İklim değişikliği
• CMIP6
• GCM
• CMhyd
• Diyarbakır

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