Evaluating simulated climate patterns from the CMIP archives using satellite and reanalysis datasets using the Climate Model Assessment Tool (CMATv1)
<p>An objective approach is presented for scoring coupled climate simulations through an evaluation against satellite and reanalysis datasets during the satellite era (i.e., since 1979). The approach is motivated, described, and applied to available Coupled Model Intercomparison Project (CMIP)...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2020-08-01
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| Series: | Geoscientific Model Development |
| Online Access: | https://gmd.copernicus.org/articles/13/3627/2020/gmd-13-3627-2020.pdf |
| Summary: | <p>An objective approach is presented for scoring coupled climate simulations through an evaluation
against satellite and reanalysis datasets during the satellite era (i.e., since 1979). The approach
is motivated, described, and applied to available Coupled Model Intercomparison Project (CMIP)
archives and the Community Earth System Model (CESM) Version 1 Large Ensemble archives with the
goal of robustly benchmarking model performance and its evolution across CMIP generations. A
scoring system is employed that minimizes sensitivity to internal variability, external forcings,
and model tuning. Scores are based on pattern correlations of the simulated mean state, seasonal
contrasts, and ENSO teleconnections. A broad range of feedback-relevant fields is considered and
summarized on discrete timescales (climatology, seasonal, interannual) and physical realms (energy
budget, water cycle, dynamics). Fields are also generally chosen for which observational
uncertainty is small compared to model structural differences.</p>
<p>Highest mean variable scores across models are reported for well-observed fields such as sea level
pressure, precipitable water, and outgoing longwave radiation, while the lowest scores are reported
for 500 <span class="inline-formula">hPa</span> vertical velocity, net surface energy flux, and precipitation minus
evaporation. The fidelity of models is found to vary widely both within and across CMIP
generations. Systematic increases in model fidelity in more recent CMIP generations are
identified, with the greatest improvements occurring in dynamic and energetic fields. Such
examples include shortwave cloud forcing and 500 <span class="inline-formula">hPa</span> eddy geopotential height and relative
humidity. Improvements in ENSO scores with time are substantially greater than for climatology or
seasonal timescales.</p>
<p>Analysis output data generated by this approach are made freely available online from a broad range
of model ensembles, including the CMIP archives and various single-model large ensembles. These
multimodel archives allow for an expeditious analysis of performance across a range of
simulations, while the CESM large ensemble archive allows for estimation of the influence of
internal variability on computed scores. The entire output archive, updated and expanded
regularly, can be accessed at <span class="uri">http://webext.cgd.ucar.edu/Multi-Case/CMAT/index.html</span> (last access: 18 August 2020).</p> |
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| ISSN: | 1991-959X 1991-9603 |