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| Titel |
Reliability of regional climate model trends |
| VerfasserIn |
Geert Jan van Oldenborgh, Francisco Doblas-Reyes, Sybren Drijfhout, Ed Hawkins |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250073645
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| Zusammenfassung |
| A necessary condition for a good probabilistic forecast is that the forecast system is shown to
be reliable: forecast probabilities should equal observed probabilities verified over a large
number of cases. As climate change trends are now emerging from the natural variability, we
can apply this concept to climate predictions and compute the reliability of simulated local
and regional temperature and precipitation trends (1950–2011) in a recent multi-model
ensemble of climate model simulations prepared for the Intergovernmental Panel on Climate
Change (IPCC) fifth assessment report (AR5). With only a single verification time, the
verification is over the spatial dimension. The local temperature trends appear reliable.
However, when the global mean climate response is factored out, the ensemble is
overconfident: the observed trend is outside the range of modelled trends in many more
regions than would be expected by natural variability and model spread. Precipitation trends
are overconfident for all trend definitions. This implies that for near-term local climate
forecasts the CMIP5 ensemble cannot simply be used as a reliable probabilistic forecast. |
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