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| Titel |
Bias correction can modify climate model simulated precipitation changes without adverse effect on the ensemble mean |
| VerfasserIn |
E. P. Maurer, D. W. Pierce |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 18, no. 3 ; Nr. 18, no. 3 (2014-03-07), S.915-925 |
| Datensatznummer |
250120298
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| Publikation (Nr.) |
 copernicus.org/hess-18-915-2014.pdf |
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| Zusammenfassung |
| When applied to remove climate model biases in precipitation, quantile
mapping can in some settings modify the simulated difference in mean
precipitation between two eras. This has important implications when the
precipitation is used to drive an impacts model that is sensitive to
changes in precipitation. The tendency of quantile mapping to alter
model-predicted changes is demonstrated using synthetic precipitation
distributions and elucidated with a simple theoretical analysis, which shows
that the alteration of model-predicted changes can be controlled by the
ratio of model to observed variance. To further evaluate the effects of
quantile mapping in a more realistic setting, we use daily precipitation
output from 11 atmospheric general circulation models (AGCMs), forced by
observed sea surface temperatures, over the conterminous United States to
compare precipitation differences before and after quantile mapping bias
correction. The effectiveness of the bias correction is not assessed, only
its effect on precipitation differences. The change in seasonal mean
(winter, DJF, and summer, JJA) precipitation between two historical periods
is compared to examine whether the bias correction tends to amplify or
diminish an AGCM's simulated precipitation change. In some cases the trend
modification can be as large as the original simulated change, though the
areas where this occurs varies among AGCMs so the ensemble median shows
smaller trend modification. Results show that quantile mapping improves the
correspondence with observed changes in some locations and degrades it in
others. While not representative of a future where natural precipitation
variability is much smaller than that due to external forcing, these results
suggest that at least for the next several decades the influence of quantile
mapping on seasonal precipitation trends does not systematically degrade
projected differences. |
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