Application of Thornthwaite moisture index to some areas in Türkiye

Öz

The source of water, the basic need of all living things in nature, is rainfall. When the same amount of rainfall is insufficient or does not fall globally, some regions experience drought problems. In some areas, floods occur due to excessive rainfall. Apart from the normal process of drought and flood, human interventions such as global warming also play an active role in the occurrence of both natural disasters. In order to track drought, several moisture indices have been developed in the literature. Moisture conditions and the extent of a water deficit in a particular area are usually ascertained using moisture indices, characterizing the equilibrium between water inflows and outflows. In this study, Thornthwaite moisture index (TMI) was used to evaluate moisture deficit. The study was conducted in the provinces of Tokat, Kayseri, Ankara, Konya, Karaman, Afyon, Denizli and Burdur. The first effort for this purpose was made according to the Innovative Polygon Trend Analysis (IPTA) of seasonal variation of rainfall and potential evapotranspiration (PET) values. Regular polygons were not obtained at any station in both data sets. Although precipitation data showed a general decreasing trend in all stations during the summer months except June, PET values had the opposite pattern. The monthly TMI index for all stations showed that there was a moisture deficit from April (except for the Afyon station) to October. A striking finding in the annual TMI results was that negative values were detected at all stations. These findings will contribute to relevant decision makers in water-related planning and awareness studies.

Anahtar Kelimeler

• Potential evapotranspiration
• rainfall
• Thornthwaite moisture index
• Innovative polygon trend analysis

Etik Beyan

There is no need to obtain permission from the ethics committee for this study.

Türkiye'deki bazı alanlara Thornthwaite nem indeksinin uygulanması

Öz

Doğadaki tüm canlıların temel ihtiyacı olan suyun kaynağı yağıştır. Küresel olarak aynı miktarda yağış yeterli olmadığında veya düşmediğinde bazı bölgelerde kuraklık sorunları yaşanmaktadır. Bazı bölgelerde aşırı yağış nedeniyle seller meydana gelmektedir. Kuraklık ve sel gibi normal süreçlerin dışında, küresel ısınma gibi insan müdahaleleri de her iki doğal afetin meydana gelmesinde etkin rol oynamaktadır. Kuraklığı takip etmek için literatürde çeşitli nem endeksleri geliştirilmiştir. Belirli bir bölgedeki nem koşulları ve su açığının boyutu genellikle su girişleri ve çıkışları arasındaki dengeyi karakterize eden nem endeksleri kullanılarak belirlenmektedir. Bu çalışmada nem açığını değerlendirmek için Thornthwaite nem endeksi (TMI) kullanılmıştır. Çalışma Tokat, Kayseri, Ankara, Konya, Karaman, Afyon, Denizli ve Burdur illerinde yürütülmüştür. Bu amaçla yapılan çalışmada ilk olarak, yağış ve PET değerlerinin aylık değişimi Yenilikçi Poligon Trend Analizi (IPTA)'ne göre yapılmıştır. Her iki veri setinde de hiçbir istasyonda düzenli poligonlar elde edilmemiştir. Yağış verileri yaz aylarında Haziran hariç tüm istasyonlarda genel bir azalan eğilim gösterse de potansiyel evapotraspirasyon (PET) değerleri tam tersi bir desene sahiptir. Tüm istasyonlar için aylık TMI sonuçları Nisan ayından (Afyon istasyonu hariç) Ekim ayına kadar bir nem açığı olduğunu göstermektedir. Yıllık TMI sonuçlarında tüm istasyonlarda negatif değerlerin tespit edilmesi ise dikkat çekici bir bulgudur. Bu bulgular su ile ilgili planlama ve farkındalık çalışmalarında ilgili karar vericilere katkı sağlayacaktır.

Anahtar Kelimeler

• Potansiyel evapotranspirasyon
• yağış
• Thornthwaite nem indeksi
• Yenilikçi poligon trend analizi

Kaynakça

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