Relative impacts of Siberian and north American snow anomalies on the winter Arctic Oscillation

Numerical model mean climatic response to realistic land surface snow forcings is evaluated for two different forcing regions, Siberia and North America. The atmospheric teleconnection pathway and negative winter AO mode response produced by the Siberia forcing, described by the authors in previous studies, is not produced by the comparable-extent North America forcing. It is shown that the combination of a large snow-forced local diabatic heating anomaly over a region of substantial stationary wave activity is required to produce strong upward wave activity flux anomalies which initiate the teleconnection pathway. These features are unique to Siberia, making it a critical region for reproducing the snow - winter AO statistical relationship evident in the observational record.