Water in Celtic Countries: Quantity, Quality and Climate Variability (Proceedings of the Fourth InterCeltic Colloquium on Hydrology and Management of Water Resources, Guimarães, Portugal, July 2005). IAHS Publ. 310, 2007, 86-93.

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The impact of changes in the weather on the surface temperatures of Lake Windermere (UK) and Lough Feeagh (Ireland)

GLEN GEORGE¹, DIANE HEWITT², ELEANOR JENNINGS³, NORMAN ALLOTT³ & PHILIP McGINNITY⁴

1 CEH Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP, UK

dgg@ceh.ac.uk

2 Freshwater Biological Association, The Ferry House, Far Sawrey, Ambleside, Cumbria LA22 OLP, UK

3 Trinity College, College Green, Dublin 2, Ireland

4 Marine Institute, Newport, County Mayo, Ireland

Abstract The surface temperatures of Lake Windermere (UK) and Lough Feeagh (Ireland) have been recorded every day since 1960. Here, we examine the factors influencing these measurements and their associated weekly variability. At both sites there was a progressive increase in the measured temperature, but the rate of increase was very much greater in Lake Windermere. The variance of the Lake Windermere temperatures was negatively correlated with the cloud cover, but there was no corresponding relationship in Lough Feeagh. Comparisons with the Lamb system of weather classification showed that the lake temperatures were closely correlated with these synoptic conditions. The highest winter temperatures were recorded during “westerly” conditions and the highest summer temperatures under “southerly” conditions. The most striking difference between the lakes was their response to cold winters and windy summers. Such results demonstrate that lakes that are topographically different “filter” the imposed climate signal in subtly different ways.

Key words climate change; Ireland; lake temperatures; UK; weather patterns

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