Increased greenhouse gases enhance regional climate response to aMaunder Minimum

摘要

[1] The climate responses to the Maunder Minimum-typetotal solar irradiance (TSI) decrease in the pre-industrial (PI)era and IPCC B1 global warming scenario are examinedusing the NCAR CAM3 coupled with a mixed-layer slabocean model. The TSI reduction shifts the AO/NAO state toa more negative index, resulting in regional surface airtemperature (SAT) change in the model. In addition, thepositive sea ice-solar radiation feedback amplifies thesurface cooling due to the TSI decrease. The globalannual average cooling effect induced by the TSI decreaseis reduced to 0.254°C in the B1 scenario from 0.347°C inthe PI epoch, this difference being due to both thesuppressed sea ice-solar radiation feedback and thestronger greenhouse effect associated with the increase ofgreenhouse gases. However, regional SAT changes in theB1 scenario are strengthened markedly due to the enhancednegative AO/NAO. The warming in the western Greenland,Central Asia and East Asia will be enhanced in the B1global warming scenario when the TSI decreases. Thesedifferences in response between the B1 and PI scenariosillustrate that the impact of multi-decadal solar variation onclimate depends on the atmospheric background trace gascomposition. A future solar grand minimum does not offsetthe CO2-induced warming in the B1 scenario, but throughthe enhanced negative AO/NAO may indeed amplify thewarming in certain regions.