Several tests can be made of climate models against observed climate
behavior, both in the recent past and in paleoclimates Climate models can never be completely validated. (See Oreskes,
N., K. Shrader-Frechette, and K. Belitz, 1994: Verification
validation, and confirmation of numerical models in the earth
sciences. Science, 263, 641-645.)
Several tests can be made of climate models against observed climate
behavior, both in the recent past and in paleoclimates
Models show considerable skill in reproducing large-scale distribution
of surface pressure, temperature, wind, and precipitation in both summer
and winter.
On regional scales (sub-continent) all models show significant
departures from observations for both temperature and precipitation.
Soil moisture comparisons are limited by lack of data, but results,
where data are available, are in qualitative agreement.
Snow cover is reasonably well simulated, except where temperatures are
too high (e.g., high latitudes in NH)
Radiative fluxes at the top of the atmosphere are simulated well in some
models.
Daily and interannual variability is mixed. Most models show good
results for some locations, but not good in others.
Model response is good for slow changes in forcing such as El Nino, Mt.
Pinatubo, wet and dry periods in the Sahel, and select periods from the
last 18,000 years.
Ocean models reproduce large-scale features fairly well
Coupled atmosphere/ocean models do reasonably well in simulations of the last ice age.
