Effect of the north Atlantic oscillation on water level fluctuations in lakes of northern Poland

Dariusz Wrzesiński,Mariusz Ptak,Katarzyna Plewa

doi:10.7163/gpol.0119

Abstract

The paper presents an analysis of correlations between water levels in Polish lakes and the rate of the North Atlantic Oscillation (NAO) in the years 1976-2010. The detailed analysis of the spatial variability of the effect of NAO on water levels in lakes concerned 19 lakes with statistically uniform hydrometric material. Two matrices were obtained for each of the lakes, composed of 156 coefficients of correlation calculated between monthly water stages and monthly and seasonal NAO indices. They provided the basis for performing two variants of classification of lakes by Ward’s method. Four typological classes were distinguished for each variant. It was determined that stronger correlations occur in the case of water stages in lakes with seasonal than those with monthly NAO indices. The strongest effect of NAO on water stages is observed in the winter-spring period. Spatial variability of the effect has been recorded, resulting from the climatic conditions of a given region. Lakes located in the south-western part of the studied area constitute an evidently separate group. In the negative phase of NAO, they are distinguished by higher water stages in the winter-spring period. This may be associated with more frequent thaws during winters, and increased supply to lakes in the period.

Highlights

Water level fluctuations in lakes are a good indicator of changes in natural and anthropogenic factors determining the hydrological conditions in catchments
The strongest effect of the North Atlantic Oscillation on water stages in the lakes is observed in the winterspring period, and coefficients of correlation with water stages in lakes in February and March are statistically significant at the level of p < 0.05 – Fig. 4
The applied research procedure and assessment of the effect of North Atlantic Oscillation (NAO) on water stages based on correlation analysis suggests that more important coefficients of correlation were obtained in the case of correlation of seasonal NAO indices with monthly water stages in lakes

Summary

Introduction

Water level fluctuations in lakes are a good indicator of changes in natural and anthropogenic factors determining the hydrological conditions in catchments. The former include precipitation amount and air temperature, influencing evaporation volume. The latter involve all kinds of hydrotechnical activities aimed at the adaptation of lakes to human economic activity. Molinos et al (2015) emphasise that water level fluctuations may cause evident socio-economic as well as environmental effects. They include among others the variability of physico-chemical water parameters, biotic changes, etc. They include among others the variability of physico-chemical water parameters, biotic changes, etc. (Stefanidis & Papastergiadou 2013; Šikić et al 2013; Cantonati et al 2014; Dembkowski et al 2014)

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Conclusion