North Atlantic Oscillation influences on Turkish lake levels

• Published in: Hydrological Processes
• Main Authors: Küçük, Murat, Kahya, Ercan, Cengiz, Taner Mustafa, Karaca, Mehmet
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2009
• Subjects: North Atlantic Oscillation; lake level; wavelet transform; periodicity; hydroclimatology; teleconnection; Turkey; El-Nino; Climate; Streamflow; Fluctuations; Variability; Signals; Van; Four Lakes; North Atlantic; North Atlantic oscillation
• Online Access: https://hdl.handle.net/20.500.11776/6500; https://doi.org/10.1002/hyp.7225

The North Atlantic Oscillation (NAO) is a large-scale mode of natural climate variability governing the path of Atlantic mid-latitude storm tracks and precipitation regimes in the Atlantic and Mediterranean sectors. The primary focus of this study is to investigate the variability of lake levels in seven lakes scattered across Turkey using the method of continuous Wavelet transforms and global spectra. The long winter (December, January, February and March) lake-level series and the NAO index (NAOI) series were subjected to wavelet transform. The global wavelet spectrum (energy spectrum of periodicities) of lake levels and winter NAOI anomalies, in most cases, revealed a significant correlation. It was shown that the Tuz, Sapanca, and Uluabat lakes reflect much stronger influences of the NAO than the other four lakes. In contrast, weak correlations were found in the coastal areas of the Mediterranean and eastern Turkey. The periodic structures Of Turkish lake levels in relation to the NAO revealed a spectrum between the 1-year and 10-year scale level. Although the periodicities of more than 10-year scale levels were detected, explaining significant relations between the NAO and these long-term periodicities remains a challenging task. The results of this study are consistent with the earlier studies concerning the teleconnection between the NAO and climate variables in Turkey. Copyright (C) 2009 John Wiley & Sons, Ltd. Istanbul Technical University Research Activities Secretariat [PN 30280] This work is supported by Istanbul Technical University Research Activities Secretariat (PN# 30280). The authors are grateful to Dr S. Kalayci (Selcuk University) for reviewing the manuscript. Dr O. Anwar Beg (Leeds Metropolitan University, UK) also helped with the final manuscript. During the preparation of this paper, the first: author (Dr Murat Kucuk) lost his life in a heartbreaking traffic accident. As a wonderful, ambitious, hard working and outgoing young scientist, his death is certainly a grievous loss to the ...