1. R.W. Arritt for the NARCCAP Team December 2006
North American Regional Climate Change Assessment Program (NARCCAP):
Phase I Preliminary Results
R.W. Arritt for the NARCCAP Team
December 2006

2. Some preliminary results
RCMs currently are completing the reanalysis-driven runs.
Results are shown here for from three RCMs.
Configuration:
common North America domain (some differences due to horizontal coordinates)
horizontal grid spacing 50 km
boundary data from NCEP/DOE Reanalysis 2
boundaries, SST and sea ice updated every 6 hours

3. Analysis Regions
Northern Plains: flat terrain, early summer precip maximum
Pacific Northwest: mountainous terrain, winter precip maximum

4. Precipitation,

5. Mean annual cycle of precipitation

6. January 1981 monthly mean 500 mb height
January 1980 – ENSO neutral
reanalysis

7. July 1982 monthly mean 500 mb height
reanalysis
reanalysis

8. Summary NARCCAP goals are:
to explore propagation of uncertainties as AOGCM results are downscaled using regional models, and
to provide multiple realizations of future climates for impacts analysis.
Preliminary results from a limited set of initial RCM output suggest:
precipitation in northern Great Plains is reasonably predicted in the RCMs
maritime influence in Pacific Northwest may extend too far inland (but need to look at other precip obs)