At the transcontinental scale, an inverse and lagged correlation has been identified for river flow in autumn between eastern North America and northern Europe (Kingston; Hannah; Lawler; McGregor). These trans-Atlantic teleconnections are stronger than the temporal autocorrelation of autumn European river flow and suggest potential for using North American river flow as a harbinger (lead-time predictor) of European river flow.
Composite 500hPa geopotential height anomaly between October high and low river flow years for rivers in eastern North America, which is indicative of inverse correlation of river flow between eastern North America and northern Europe.
Innovative methods have also been developed to analyse:
River Seine precipitation and discharge variability over the last half-century have been quantified and links were assessed with the North Atlantic Oscillation (NAO). LOESS filtering associated with continuous wavelet transform revealed the presence of a long-term trend, and 5-9 year and 17 year fluctuations(Massei and Laignel);
the role of basin properties as a modifier of the climate signal in river flows. River flow data across mainland Great Britain showed that regional climate variables (precipitation, potential evaporation, soil moisture deficit) have stronger association with seasonal flows than atmospheric circulation (NAO) (Laizé; Hannah). Ongoing research on large-scale climate-hydrology interactions is focuses the UK (Lavers, Prudhomme, Hannah), Turkey (Şaris, Hannah, Eastwood) and around the Mediterranean (Kordomenidi, Hannah). At an even larger spatial scale, climate-river flow links have been assessed across lowland and montane environments of northern Europe (Kingston, Hannah), and
association between circulation types (CTs) and flood occurrence across Europe. Relationships were assessed for 488 river basins, including data from EWA, using CTs from 64 weather type catalogues developed within COST733 Action (Prudhomme, Genevier). As well as floods, the association between CT frequencies and the development of regional hydrological drought has been investigated for Great Britain and Denmark (Fleig, Tallaksen, Hisdal, Hannah).