DOĞU AKDENİZ YÜZEY AKINTILARININ UÇ DEĞER ANALİZİ, YÖNSELLİĞİ VE ZAMANSAL KARAKTERİSTİKLERİ

Year 2025, Volume: 30 Issue: 1, 201 - 220, 28.04.2025

Tahsin Görmüş

https://doi.org/10.17482/uumfd.1590330

Abstract

Çalışmada Doğu Akdeniz’de yer alan seçili noktalarda akıntı hızlarının uzun dönem ve uç değer istatistiklerine yer verilmiştir. 1987 ile 2022 arasındaki 36 yılı kapsayan saatlik deniz yüzeyi akıntı hızı zaman serisi, yönden bağımsız analizin yanı sıra sekiz temel yönde akıntı hızı büyüklüklerinin ayrıştırılmasıyla da incelenmiş ve uzun dönemle birlikte uç değer istatistiği için de yöne bağlı bir analiz gerçekleştirilmiştir. Yıllık maksimum değerlere dayalı Gumbel dağılımı ile eşik üstü tepe değerler ile hesaplanan Genelleştirilmiş Pareto Dağılımı (GPD) iki yöntem olarak seçilmiş ve karşılaştırılmalarına yer verilmiştir. Uzun dönem akıntı gülleri incelendiğinde en yüksek akıntı hızı değerlerinin genellikle Kuzey Ege’de görüldüğü ve en yüksek aralığı gösteren 0,3 m/s üzeri akıntıların en çok P1 (Kuzey Ege), P5 (Ege) ve P10 (Doğu Akdeniz) noktalarında görüldüğü ve sırasıyla Güney, Kuzeybatı ve Batı yönlü olduğu anlaşılmıştır. 100 yıllık tekerrür değerlerinin analiz noktalarında Gumbel dağılımı için 0,9 ile 1,5 m/s, GPD için ise 0,8 ile 1,5 m/s arasında değiştiği ve uç değer istatistiğindeki analiz noktaları arasında en çok görülen baskın yönün Kuzeydoğu olduğu anlaşılmıştır. Akıntı hızlarının yönselliği incelendiğinde uzun dönem ve uç değer istatistiklerinden elde edilen baskın yönlerin her durumda örtüşmeyebileceği sonucuna varılmıştır. İki yöntem ile elde edilen tekerrür değerlerinin farkı analiz noktaları baz alındığında %18’e kadar çıkmaktadır.

Keywords

Yüzey Akıntıları , Akdeniz , Ege Denizi , Uç Değer İstatistiği , Yönsel Analiz

Extreme Value Analysis, Directionality and Temporal Characteristics of Surface Currents in the Eastern Mediterranean Sea

Abstract

In this study, long term and extreme value analysis of current velocities at selected points in the Eastern Mediterranean are presented. The hourly current velocity time series covering 36 years between 1987 and 2022 were analyzed by decomposing the magnitudes of the current velocity in eight directions, and a direction-dependent analysis was performed for the long term and extreme value statistics. Gumbel Distribution and Generalized Pareto Distribution (GPD) are selected as two methods. It was found that the highest current velocity values were generally observed in the North Aegean. The currents above 0,3 m/s were mostly observed at P1 (North Aegean), P5 (Aegean) and P10 (Eastern Mediterranean) analysis points and the South, Northwest and West directions, respectively. The 100-year values ranged between 0,9 and 1,5 m/s for the Gumbel distribution and between 0,8 and 1,5 m/s for the GPD at the analysis points, and the dominant direction among the points in the extreme value statistics was found to be Northeast. It is concluded that the dominant directions obtained from the long-term and extreme value statistics may not coincide in all cases. The difference in return values between the two methods reaches up to 18% in the analysis points.

Keywords

Surface Currents , Mediterranean Sea , Aegean Sea , Extreme Value Analysis , Directional Analysis

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