Tuesday, 16 January 2007: 1:45 PM
Improved monitoring of hemispheric snow cover extent
214B (Henry B. Gonzalez Convention Center)
It has been 40 years since satellite-derived maps of Northern Hemisphere snow cover extent (SCE) began being produced by National Oceanic and Atmospheric Administration meteorologists. No other environmental variable has been mapped from satellite data in a generally consistent manner for such a long period. Information generated from these maps has been used in international assessments of climate variability and change, and in numerous investigations regarding the role of snow cover in the climate system. Despite their proven climate utility, meteorological forecasting has long been the driving force behind producing these maps. As such, changes (documented and undocumented) in mapping methodologies have occurred over time, without a focus on their climatological continuity. In particular, 1999 brought a change from weekly to daily maps and a greatly increased resolution to the map's digitized grid. Members of our Global Snow Lab, as well as others elsewhere, have kept a watchful eye on changes in this satellite environmental data record (EDR). We saw the need to thoroughly scrutinize the EDR and to develop a satellite SCE climate data record (CDR). This presentation will discuss efforts within the Global Snow Lab to do just that, and will introduce this CDR. Comparisons of climatologies and time series between the new CDR and the past EDR will be presented, along with estimates of CDR error limits. Updated time series analyses of regional to hemispheric SCE through 2006 will also be discussed, along with efforts underway that will integrate visible and microwave satellite and station-observed estimates of extent and depth into valuable new CDRs.