Middle- to late-Holocene storminess in Brittany (NW France): Part II – The chronology of events and climate forcing
Brigitte van Vliët-Lanoé|Aurélie Penaud|Alain Hénaff|Christophe Delacourt|Assia Fernane|Jérôme Goslin|Bernard Hallégouët|Erwan Le Cornec
This study focuses on the recurring climate conditions required for largest storms occurring in NW France (Brittany). It is based analysed records of storm events along Western Brittany coast (see Part I). In this manuscript (Part II), recurrence explored with forcing mechanisms. Periods more frequent over two last centuries are first order to link these possible mechanisms (North Atlantic Oscillation (NAO) and Multidecadal (AMO) modes) triggering most destructive storms. Then, palaeostorm discussed at Holocene scale, from 6000 yr BP present, verify Most recorded appear be linked cooling episodes, mostly winter, a transition or negative winter NAO mode, positive AMO mode. Extreme occur immediately prior ‘Medieval Warm Period’ (MWP). Maximum effects reached onset MWP during Maunder Dalton solar minima. Low activity occurred Spörer Minimum an acceleration Meridional Overturning Circulation (AMOC). Main triggers seem correspond mode unstable jetstream configuration driving NAO. study, four specific weather configurations were defined explain each type storminess. The strongest low decennial-negative modes (e.g. ‘Little Ice Age’), high association dominant modes, as early Middle Age present-day period. Fresh warm oceans stormy but very sting frequency. Although agreement orbital glacial history, increasing frequency intensity probably partly biased by continuous sea-level rise resulting erosion.
The Holocene