Northern Hemisphere atmospheric pattern enhancing Eastern Mediterranean Transient-type events during the past 1000 years

Aleix Cortina-Guerra (1) , Juan José Gomez-Navarro (2) , Belen Martrat (1) , Juan Pedro Montávez (2) , Alessandro Incarbona (3) , Joan O. Grimalt (1) , Marie-Alexandrine Sicre (4) , P. Graham Mortyn (5)

1 IDAEA - Institute of Environmental Assessment and Water Research
2 Universidad de Murcia
3 DiSTeM - Dipartimento di Scienze della Terra e del Mare [Palermo]
4 VOG - Variabilité de l'Océan et de la Glace de mer
5 ICTA - Institut de Ciencia i Tecnologia Ambientals

High-resolution climate model simulations for the last millennium were used to elucidate the main winter Northern Hemisphere atmospheric pattern during enhanced Eastern Mediterranean Transient (EMT-type) events, a situation in which an additional overturning cell is detected in the Mediterranean at the Aegean Sea. The differential upward heat flux between the Aegean Basin and the Gulf of Lion was taken as a proxy of EMT-type events and correlated with winter mean geopotential height at 500 mbar in the Northern Hemisphere (20–90∘ N and 100∘ W–80∘ E). Correlations revealed a pattern similar to the East Atlantic/Western Russian (EA/WR) mode as the main driver of EMT-type events, with the past 1000 years of EA/WR-like mode simulations being enhanced during insolation minima. Our model results are consistent with alkenone sea surface temperature (SST) reconstructions that documented an increase in the west–east basin gradients during EMT-type events.

Domaines: Climatologie; Océan, Atmosphère

Aleix Cortina-Guerra, Juan José Gomez-Navarro, Belen Martrat, Juan Pedro Montávez, Alessandro Incarbona, et al.. Northern Hemisphere atmospheric pattern enhancing Eastern Mediterranean Transient-type events during the past 1000 years. Climate of the Past, 2021, 17 (4), pp.1523 - 1532. ⟨10.5194/cp-17-1523-2021⟩. ⟨hal-03414828⟩