The winter Arctic Oscillation and the timing of snowmelt in Europe

Abstract

Observations indicate earlier spring snowmelt in the northern hemisphere. We hypothesize that increased temperatures and decreased precipitation due to a positive trend in the winter Arctic Oscillation (AO) have advanced the date of snowmelt. To test this, we modeled snowmelt using the Simple Biosphere model, Version 2 (SiB2) and the National Centers for Environmental Prediction (NCEP) reanalysis from 1958-2002. The simulated snowmelt dates are consistent with dates derived from National Oceanic and Atmospheric Administration (NOAA) weekly snow charts. The winter AO exerts the strongest influence on the timing of snowmelt in northern Europe, with a weaker influence in eastern Siberia and almost no influence in North America. The winter AO trend can statistically explain 20-70% of simulated snowmelt trends in northern Europe. Copyright 2004 by the American Geophysical Union.