Drought Analysis in Long and Short Term Periods: Bursa Case

Öz

Natural disasters are important in human life. Drought is a disaster that depends on climatic and regional characteristics and affects all lives negatively. A detailed analysis of the region is necessary to determine the drought and take necessary measures. The researchers used different drought indices to determine drought. Standardized Precipitation Index (SPI) is one of the most commonly used drought indices that accounts different time scales. In this study, Bursa, Iznik, Keles, Mustafakemalpaşa, Uludag stations with long-term precipitation data in Bursa were examined for 1969-2015. The trend of precipitation data was determined by linear regression analysis. Precipitation data were standardized and evaluated according to the runs analysis. Lastly, drought analysis was performed for the periods 1, 3, 6, 9, 12, 24 and 48 months by the Standard Precipitation Index (SYI) method, which is widely used in our country and in the world. There was no significant trend in annual and monthly rainfall data. It was found that the monthly precipitation showed downward trend at Iznik, Keles, Uludag stations in December and at Bursa station in October. A statistically significant trend (5% risk) was not found in other months. Results of Standardized Precipitation Index are showed similarity which drought, normal and wet period rations in all stations. However, while normal or mild droughts are more frequent in short-term periods (3-6 months), severe or very severe droughts have been observed over long-term periods (12-24-48 months).

Anahtar Kelimeler

• Drought,Standard Precipitation Index,Runs Analysis,Bursa

Uzun ve Kısa Süreli Periyotlarda Kuraklık Analizi: Bursa Örneği

Öz

İnsan yaşamında doğal afetler önemli yer alır. Kuraklık, iklimsel ve bölgesel özelliklere bağlı olan ve tüm canlı yaşamını olumsuz etkileyen bir afettir. Kuraklığın belirlenmesi ve gerekli tedbirlerin alınabilmesi için bölgenin ayrıntılı analizi gerekmektedir. Araştırmacılar, kuraklığı saptamak için farklı kuraklık indislerini kullanmışlardır. Standart Yağış İndisi (SYİ), farklı zaman ölçeklerinde hesapların yapılabildiği ve literatürde en sık kullanılan kuraklık indislerinden biridir. Bu çalışmada, Bursa ilinde uzun süreli yağış verisi bulunan Bursa, İznik, Keleş, Mustafakemalpaşa ve Uludağ istasyonları 1969-2015 dönemi için incelenmiştir. Yağış verilerinin eğilimi olup olmadığı lineer regresyon analiziyle belirlenmiştir. Yağış verileri standardize edilerek gidişler analizine göre değerlendirilmiştir. Son olarak da ülkemizde ve dünyada yaygın olarak kullanılan Standart Yağış İndisi (SYİ) yöntemi ile 1, 3, 6, 9, 12, 24 ve 48 aylık zaman periyotları için kuraklık analizi yapılmıştır. Yıllık ve aylık yağış verilerinde önemli bir eğilim saptanmamıştır. Aralık ayında İznik, Keleş, Uludağ istasyonları azalma eğilimi; Ekim ayında Bursa istasyonu azalma eğilimi gösterdiği bulunmuştur. İstatistiksel olarak anlamlı eğilim (%5 risk) diğer aylarda saptanmamıştır. Standart Yağış İndisi (SYİ) analizi sonuçlarında istasyonların kurak, normal veya sulak periyot oranları benzerlik göstermiştir. Bununla birlikte, kısa süreli periyotlarda (3-6 ay) normal veya hafif kuraklıklara daha sık rastlanırken, uzun süreli periyotlarda (12-24-48 ay) şiddetli ve çok şiddetli kuraklık gözlenmiştir.

Anahtar Kelimeler

• Kuraklık,Standart Yağış İndisi,Gidişler Analizi,Bursa

Kaynakça

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