Externally forced and internal variability in ensemble climate simulations of the Maunder Minimum

The response of the climate system to natural, external forcing during the Maunder Minimum (ca. a.d. 1645–1715) is investigated using a comprehensive climate model. An ensemble of six transient simulations is produced in order to examine the relative importance of externally forced and internally ge...

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Bibliographic Details
Published in:Journal of Climate
Main Authors: Yoshimori, Masakazu, Stocker, Thomas F., Raible, Christoph C., Renold, Manuel
Format: Article in Journal/Newspaper
Language:English
Published: American Meteorological Society 2005
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Online Access:https://boris.unibe.ch/158286/1/yoshimori05jc.pdf
https://boris.unibe.ch/158286/
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Summary:The response of the climate system to natural, external forcing during the Maunder Minimum (ca. a.d. 1645–1715) is investigated using a comprehensive climate model. An ensemble of six transient simulations is produced in order to examine the relative importance of externally forced and internally generated variability. The simulated annual Northern Hemisphere and zonal-mean near-surface air temperature agree well with proxy-based reconstructions on decadal time scales. A mean cooling signal during the Maunder Minimum is masked by the internal unforced variability in some regions such as Alaska, Greenland, and northern Europe. In general, temperature exhibits a better signal-to-noise ratio than precipitation. Mean salinity changes are found in basin averages. The model also shows clear response patterns to volcanic eruptions. In particular, volcanic forcing is projected onto the winter North Atlantic Oscillation index following the eruptions. It is demonstrated that the significant spread of ensemble members is possible even on multidecadal time scales, which has an important implication in coordinating comparisons between model simulations and regional reconstructions.