Abrupt fluctuations in intra-seasonal snow extent

Northern Hemisphere (NH) continental snow cover during the 2009/10 winter was the second most extensive during the satellite era and most extensive over North America (NA). This was followed by the 4th least extensive spring 2010 NH extent and least extensive NA cover. Such abrupt fluctuations within the NH snow cycle will be examined using a newly-completed snow cover extent (SCE) climate data record (CDR).

The SCE CDR was derived from a thorough reanalysis of NOAA satellite-derived maps of NH continental SCE, maps that date back to late 1966. We relied on comparisons between climatologies of the first 33 years of coarse-scale weekly NOAA maps and the most recent nine years of finer daily maps produced by NOAA, currently at the multi-agency National Ice Center. The reanalysis also benefited from a two-year overlap of the independently-produced daily and weekly products and the expertise of the Rutgers Global Snow Lab staff and colleagues elsewhere who were consulted throughout the project.

With this improved long-term satellite product we will document abrupt fluctuations of SCE on a variety of scales. This will include intra-seasonal variations within a snow season (such as described above), within season variability between Eurasia and North America and temporal trends associated with both. A preliminary assessment of associations of these results with large-scale atmospheric patterns (e.g. surface air temperature, mid-troposphere geopotential height) will be touched on here and discussed more fully in a companion paper at this meeting.