Historical Average Winter Temperature for Jan-Mar (1968-1999) from NCEP climate

Climate data (NCEP: Average Winter Temperature for Jan-Mar, 1968-1999) have been generated using a regional climate model called RegCM3 using boundary conditions from observations or general circulation models for historical conditions, and from GCM projections for future conditions.

Regional climate model description: RegCM3 is the third generation of the Regional Climate Model originally developed at the National Center for Atmospheric Research during the late 1980s and early 1990s. Details on current model components and applications of the model can be found in numerous publications (e.g., Giorgi et al, 2004a,b, Pal et al, 2007), the ICTP RegCNET web site (http://users.ictp.it/RegCNET/model.html), and the ICTP RegCM publications web site (http://users.ictp.it/~pubregcm/RegCM3/pubs.htm ). The Western North America domain has a horizontal grid spacing of 15 km and 18 vertical levels.

RegCM3 requires time-dependent lateral (wind, temperature, and humidity) and surface [surface pressure and sea surface temperature (SST)] boundary conditions that are updated every 6 hours of simulation. Lateral boundary conditions are derived from General Circulation Model (GCM) output or observations (e.g. NCEP).

Additional information: http://regclim.coas.oregonstate.edu/RCCV/RCCV_States_advanced.html for data visualization and http://regclim.coas.oregonstate.edu/ for detailed documentation.

The NCEP RegCM3 simulation is driven by atmospheric and surface fields derived from the NCEP-DOE/NCAR Reanalysis project from NOAA. The reanalysis project assimilates a large array of observed atmospheric and surface data into the NOAA Atmospheric-GCM which is run to produce spatially and temporally continuous global data sets. The NCEP Reanalysis data thus provides a gridded optimal estimate of climate variables constrained by observations. It is standard practice in regional climate modeling to use reanalysis products as driving boundary conditions because, in theory, the resulting simulations should be in the best agreement with observations. Additionally, the NCEP simulations provide a spatially complete and internally consistent gridded set of climate and surface variables that can be used 'off line' to calibrate process models.