UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Impact of global SST gradients on the Mediterranean runoff changes across the Plio-Pleistocene transition

Colleoni, F; Cherchi, A; Masina, S; Brierley, CM; (2015) Impact of global SST gradients on the Mediterranean runoff changes across the Plio-Pleistocene transition. Paleoceanography , 30 (6) pp. 751-767. 10.1002/2015PA002780. Green open access

[thumbnail of Colleoni_et_al-2015-Paleoceanography.pdf]
Preview
Text
Colleoni_et_al-2015-Paleoceanography.pdf

Download (9MB) | Preview

Abstract

This work explores the impact of the development of global meridional and zonal sea surfacetemperature (SST) gradients on the Mediterranean runoff variability during the Plio-Pleistocene transition,about 3 Ma. Results show that total annual mean Pliocene Mediterranean runoff is about 40% larger thanduring the preindustrial period due to more increased extratropical specific humidity. As a consequenceof a weakened and extended Hadley cell, the Pliocene northwest Africa hydrological network producesa discharge 30 times larger than today. Our results support the conclusion that during the Pliocene, theMediterranean water deficit was reduced relative to today due to a larger river discharge. By means ofa stand-alone atmospheric general circulation model, we simulate the separate impact of extratropicaland equatorial SST cooling on the Mediterranean runoff. While cooling the equatorial SST does not implysignificant changes to the Pliocene Mediterranean hydrological budget, the extratropical SST coolingincreases the water deficit due to a decrease in precipitation and runoff. Consequently, river dischargefrom this area reduces to preindustrial levels. The main teleconnections acting upon the Mediterraneanarea today, i.e., the North Atlantic Oscillation during winter and the “monsoon-desert” mechanism duringsummer already have a large influence on the climate of our Pliocene simulations. Finally, our results alsosuggest that in a climate state significantly warmer than today, changes of the Hadley circulation couldpotentially lead to increased water resources in northwest Africa.

Type: Article
Title: Impact of global SST gradients on the Mediterranean runoff changes across the Plio-Pleistocene transition
Open access status: An open access version is available from UCL Discovery
DOI: 10.1002/2015PA002780
Publisher version: http://dx.doi.org/10.1002/2015PA002780
Language: English
Additional information: ©2015. American Geophysical Union. All Rights Reserved.
Keywords: Mediterranean runoff, Pliocene climate, climate modeling, SST gradient, Plio-Pleistocene transition
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL SLASH
UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS
UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS > Dept of Geography
URI: https://discovery.ucl.ac.uk/id/eprint/1474373
Downloads since deposit
66Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item