Gates, W. L. 1995: An overview of AMIP results. Abstracts
of the First International AMIP Scientific Conference, Monterey, California,
9.
AMIP has been a useful start toward the adoption of community-wide
standards for the documentation, analysis and intercomparison of global
atmospheric climate models and for the identification of their systematic
errors. A preliminary analysis of the zonally-averaged results of the 30
participating AMIP models shows that: (1) Most models provide a credible
simulation of the mean seasonal structure of the large-scale circulation,
although a few models are outliers. (2) The models display a characteristic
spread in their simulations that is nearly independent of latitude and
season. (3) The seasonal differences among the models are greater than
the variability among ensemble simulations of a single model. (4) Outliers
aside, no single model performs best in all respects. (5) The reasons for
a particular model's behavior are difficult to determine from the AMIP
data alone, although there does not appear to be a strong dependence on
resolution. (6) There are common seasonal errors apparent in some variables,
although the observational data are of uncertain reliability in many cases.
(7) While models on the whole appear to be slowly improving, the lack of
systematic performance data prior to AMIP makes estimation of the rate
of improvement difficult. Other parts of the standard output and the preliminary
results from the diagnostic subprojects show that there are strong geographical
variations in the accuracy of the models' performance, and that both the
accuracy and agreement among the models generally decrease as smaller regions
and shorter time scales are examined. It is also clear that a single statistical
measure cannot adequately portray model performance. Any extension or expansion
of AMIP should include improvements in the experimental design and a wider
range of standardized output coordinated with reanalysis in order to permit
more insightful diagnosis and accelerated model improvement.