Regional Climate Simulations
It is essential to determine the local and regional
impacts of global warming. Global climate models, driven by
increasing concentrations of greenhouse gases are useful, but are
typically run at grid spacings of 100-200 km and thus lack the
resolution to realistically simulate local weather features driven
by terrain, land-water contrasts, surface variability, and
Terrain maps of a typical global climate model (left) and weather
forecast model (12-km grid spacing) on the right.
To deal with this issue, this project is running a
high-resolution weather forecasting model (WRF) at 12-km or 4-km
grid spacing over a century or more for the western U.S. and other
regions (such as southeast China).
Importantly, we are running an ensemble of many of such
forecasts to determine the uncertainties and range of possible
regional climate projections. To do this, we have secured
all the CMIP-5 climate simulations that have 6-hr output and have
run 130-year simulations (1970-2000) for them (12 in all).
Such high-resolution dynamical downscaling of global climate
models, has produced a number of surprising results, suggesting
increased springtime low clouds over the coastal Pacific
Northwest, bands of enhanced warming from melting snowpack, drying
zones in the lee of major barriers, and decreasing easterly
winds. Substantial work is now ongoing for varying emission
scenarios, more global climate models, and in understanding the
local/regional impacts of global warming.