Discrete wavelet analysis of the influence of the North Atlantic Oscillation on Baltic Sea level

Mean sea level (MSL) in the Baltic Sea is influenced by several factors and therefore presents a complex behaviour over a wide range of time-scales. This work performs a multi-scale analysis of MSL variability in the Baltic Sea using discrete wavelet analysis. The North Atlantic Oscillation (NAO) is...

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Bibliographic Details
Published in:Tellus A: Dynamic Meteorology and Oceanography
Main Authors: A. Bastos, R. M. Trigo, S. M. Barbosa
Format: Article in Journal/Newspaper
Language:English
Published: Stockholm University Press 2013
Subjects:
NAO
MSL
Online Access:https://doi.org/10.3402/tellusa.v65i0.20077
https://doaj.org/article/c1ade082173340bb88ab96114fa70bf6
Description
Summary:Mean sea level (MSL) in the Baltic Sea is influenced by several factors and therefore presents a complex behaviour over a wide range of time-scales. This work performs a multi-scale analysis of MSL variability in the Baltic Sea using discrete wavelet analysis. The North Atlantic Oscillation (NAO) is well known for having a strong influence in MSL variability over the Baltic; however, the relationship between MSL and NAO at different time-scales is still little understood. In this work a comparison of MSL and NAO variability is performed for a wide range of temporal scales, uncovering distinct relationships in high-frequency and long-term temporal variability. The annual and sub-annual scales are found to account for more than 50% of the total MSL variability. The MSL annual cycle is analysed and a shift from low to high amplitude values is identified in the 1970s for most stations. MSL is found to be anti-correlated to NAO at short time-scales while on the long-term NAO and MSL appear to be positively correlated for most stations. The physical mechanisms behind these distinct relationships deserve deeper study.