Links between multidecadal and interdecadal climatic oscillations in the North Atlantic and regional climate variability of northern France and England since the 17th century

Bastien Dieppois (1) , Alain Durand (1) , Matthieu Fournier (1) , Nicolas Massei (1)

1 M2C - Morphodynamique Continentale et Côtière

Knowledge of the variability of climate in the past is essential for understanding current climatic changes. Therefore, we investigated two temperature indices and seven rainfall time series of northwestern Europe since the 17th century. Trends and multidecadal to interdecadal variability are similar in England and northern France for temperature, whereas a strong regional contrast is evident between the two regions for rainfall. Multidecadal and interdecadal variability displays several periods of enhanced amplitude for both temperature and rainfall that may be related to large-scale climate control. On these scales, temperatures in both England and France display phase opposition with the Atlantic Multidecadal Oscillation (AMO) before 1800, while they are in-phase afterward, as determined by wavelet coherence. On the other hand, the relationships between temperature and the North Atlantic Oscillation (NAO) are weak across multidecadal and interdecadal scales for the whole period under study. For rainfall, coherence with the AMO is observed for scales at around 30-60 years, whereas coherence with the NAO is detected on 50-80 year scales and interdecadal 16-23 year scales. However, relationships between rainfall variability and North Atlantic climate indices are highly contrasted depending on the region considered. Finally, the results of a mixed spectral/empirical orthogonal function analysis of mean sea level pressure on these co-oscillation time scales highlight not only NAO regimes but also other patterns, explaining a nonnegligible amount of variance during certain time periods.

Domaines: Interfaces continentales, environnement; Milieux et Changements globaux

Bastien Dieppois, Alain Durand, Matthieu Fournier, Nicolas Massei. Links between multidecadal and interdecadal climatic oscillations in the North Atlantic and regional climate variability of northern France and England since the 17th century. Journal of Geophysical Research: Atmospheres, 2013, 118, pp.4359-4372. ⟨10.1002/jgrd.50392⟩. ⟨hal-02327491⟩