Regional sensitivities of mean and peak river discharge to climate variability in Europe

• Published in: Journal of Geophysical Research
• Main Authors: Bouwer, L.M., Vermaat, J.E., Aerts, J.C.J.H.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2008
• Subjects: Arctic; North Atlantic; North Atlantic oscillation
• Online Access: https://research.vu.nl/en/publications/f398d0b3-4fb5-4801-bed3-13b73a2c8cc9; https://doi.org/10.1029/2008JD010301

Variability of atmospheric circulation is thought to be the most important factor causing annual and decadal variability of fresh water fluxes from the continents. Previous studies, however, have rarely established the sensitivity of the basins to atmospheric circulation variability. Here we present an analysis of long-term (>30 years) links between atmospheric forcing and winter (December-February) precipitation, and sensitivities of annual mean and maximum winter discharges observed at up to 608 stations across Europe. Links to four atmospheric indices are examined: the North Atlantic Oscillation (NAO) index, the Arctic Oscillation (AO) index, the frequency of west circulation (FWC) as described by the subjective Grofiwetterlagen classification, and the north to south sea level pressure difference across the European continent (SLPD). The results show that annual maximum discharges are more sensitive to variability of atmospheric circulation than mean discharges. Mean discharges vary on average between 8 and 44%, while peak discharges vary between 10 and 54% per unit index change. Discharges in Iberia and Scandinavia are more sensitive than those in central and northwest Europe. Discharge closely follows variability of atmospheric circulation. Compared with FWC and SLPD, the NAO and AO indices have only limited use for analyzing climate impacts in river basins in northwest Europe. Copyright 2008 by the American Geophysical Union.