In order to better understand the synoptic-scale evolution of individual fall snow events over Siberia, an analysis of the synoptic structure of both select individual snow events and composites for the 1979-2010 period is conducted.  The motivation of this research is to aid in work exploring the large-scale response to changes in Eurasian snow cover and related changes to the surface energy balance.  Case studies for October 2009, which was a period of rapid and large changes in Eurasian snow cover, suggest that the synoptic structure of the storms is the result of the interaction of propagating short wave features with the quasi-stationary mean circulation.  Relatively modest precipitation amounts appear to be associated with large changes in snow cover in this season, although it is not yet clear whether this is a general relationship.  The 2009 case studies are  compared with long-term synoptic composites, to assess how the structure and interactions observed in the case studies correlate to the general relationships.

In addition to an examination of synoptic structure, trajectory analysis using the NOAA HYSPLIT model is also used to better understand the sources of moisture for these snow-producing systems.  We hypothesize that the coastal Arctic Ocean is a moisture source for the region and that, therefore, decreases in fall sea ice provide a greater source of moisture and more snowfall over the continent.  Preliminary analysis for the 2009 case studies does indeed show moisture originating over the Arctic Sea, and composites for 1979-2010 are being conducted.