Linking North Atlantic ocean-atmosphere teleconnection patterns and hydrogeological responses in temperate groundwater systems

Climate signals exhibit periodicity over a range of frequencies (e.g. diurnal, seasonal, annual and longer term climate phenomena) that are modified as they propagate through the terrestrial water cycle. Much of both our present understanding and modelling of temperate hydrological and hydrogeological systems relies on the preservation of high-frequency signals (e.g. diurnal and seasonal cycles: Holman et al., 2009; Alley et al., 2002). However, there is evidence to suggest that low-frequency oscillations in rainfall, temperature and evapotranspiration are linked to the El Ni ˜no Southern Oscillation (Jones and Banner, 2003), Pacific Decadal Oscillation (Gurdak et al., 2007), North Atlantic Oscillation (NAO) (Schroder and Rosbjerg, 2004; Qian and Saunders, 2003) and other ocean–climate cycles.