Solar forcing synchronizes decadal North Atlantic climate variability

• Published in: Nature Communications
• Main Authors: Thieblemont, Remi, Matthes, Katja, Omrani, Nour-Eddine, Kodera, Kunihiko, Hansen, Felicitas
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Publishing Group 2015
• Subjects: North Atlantic; North Atlantic oscillation
• Online Access: https://oceanrep.geomar.de/id/eprint/29890/; https://oceanrep.geomar.de/id/eprint/29890/1/ncomms9268.pdf; https://doi.org/10.1038/ncomms9268

Quasi-decadal variability in solar irradiance has been suggested to exert a substantial effect on Earth’s regional climate. In the North Atlantic sector, the 11-year solar signal has been proposed to project onto a pattern resembling the North Atlantic Oscillation (NAO), with a lag of a few years due to ocean-atmosphere interactions. The solar/NAO relationship is, however, highly misrepresented in climate model simulations with realistic observed forcings. In addition, its detection is particularly complicated since NAO quasi-decadal fluctuations can be intrinsically generated by the coupled ocean-atmosphere system. Here we compare two multi-decadal ocean-atmosphere chemistry-climate simulations with and without solar forcing variability. While the experiment including solar variability simulates a 1–2-year lagged solar/NAO relationship, comparison of both experiments suggests that the 11-year solar cycle synchronizes quasi-decadal NAO variability intrinsic to the model. The synchronization is consistent with the downward propagation of the solar signal from the stratosphere to the surface.