I worked as a project scientist for the
U.S. National Assessment
of the potential consequences of climate variability
and change. I served as the
climate scenarios
coordinator for the National Assessment Working Group
and the National Assessment Coordination Office in Washington
D C. I was located with the
Climate and Global Dynamics Division
at the National Center
for Atmospheric Research
in Boulder, Colorado. The simulations used in
the U.S. National Assessment all involve coupled atmosphere-ocean
general circulation models (GCMs) with transient greenhouse
gases and sulfate aerosols. These simulations include
the CCCma
CGCM1
(Canadian) model and the Hadley
HADCM2
model (British). Data from the
MPI/DKRZ
ECHAM4/OPYC3 (German) model, using
similar emissions scenarios, are also available.
NCAR has completed several new simulations that include
a) multiple greenhouse gases b) more realistic sulfate
emissions scenario c) actual sulfate chemistry model
and a d) coupled atmosphere-ocean GCM that is not flux-corrected.
The VEMAP
project has downscaled the historical station
data from NOAA's National Climatic Data Center's U.S.
Historical Climate Network (
HCN)
and other cooperative network stations, plus USFS and
BLM SnoTel stations for high elevation precipitation
to account for elevational effects.
The future GCM data is applied to this data set to produce
a downscaled version of the GCM output.
Emissions
Scenarios: These
figures are the equivalent CO2 concentrations and
sulfate emissions that were used to force the GCM simulations
used in the U.S. National Assessment
.
Intermodel Comparisons: These figures are the global and U.S. temperature and precipitation trends for several GCMs using an approximately 1% increase in greenhouse gases plus sulfate aerosols.
Time Series: These figures are the minimum temperature, maximum temperature, and precipitation time series averaged over the U.S. for the HCN and VEMAP-processed data.
Maps: These figures are the temperature and precipitation trends observed over the 20th century and projected for the 21st century by the Canadian and Hadley models.