EGU General Assembly 2021
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Enhanced humidity in SW Iberia driven by the combination of insolation and ice-sheet forcing during MIS 13 interglacial

Dulce Oliveira1,2, Stéphanie Desprat3,4, Qiuzhen Yin5, Teresa Rodrigues1,2, Filipa Naughton1,2, Ricardo Trigo6, Qianqian Su5, Joan O. Grimalt7, Montserrat Alonso-Garcia8, Antje H.L. Voelker1,2, Fátima Abrantes1,2, and Maria Fernanda Sánchez Goñi3,4
Dulce Oliveira et al.
  • 1CCMAR, Centro de Ciências do Mar, Universidade do Algarve. NIF: 506197760, Faro, Portugal (
  • 2Divisão de Geologia e Georecursos Marinhos, Instituto Português do Mar e da Atmosfera (IPMA), Av. Doutor Alfredo Magalhães Ramalho 6, 1495-165 Algés, Portugal
  • 3Ecole Pratique des Hautes Etudes (EPHE, PSL University), F-33615 Pessac, France
  • 4Université Bordeaux, EPOC, UMR 5805, F-33615 Pessac, France
  • 5Georges Lemaître Center for Earth and Climate Research, Université catholique de Louvain, Belgium
  • 6Instituto Dom Luiz, Universidade de Lisboa, 1749-016 Lisboa, Portugal
  • 7Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA), Spanish Council for Scientific Research (CSIC), 08034 Barcelona, Spain
  • 8Department of Geology- Paleontology, University of Salamanca, Pza. de los Caídos, 37008 Salamanca, Spain

Marine Isotope Stage (MIS) 13, ~500 ky ago, represents a Quaternary interglacial of primary interest due to the unexpected enhancement of monsoon systems under a cool climate characterised by low atmospheric CO2 and larger ice volume than the present interglacial. Yet, key questions remain about its regional expression (intensity, climate variability, length) and underlying forcing factors. Here we examine the SW Iberian vegetation and terrestrial climate during MIS 13 directly compared with the sea surface temperatures using sediments from IODP Site U1385, and combine those terrestrial-marine profiles with climate-model experiments. We show for the first time that MIS 13 stands out for its large forest expansions with a reduced Mediterranean character alternating with muted forest contractions, indicating that this stage is marked by a cool-temperate climate regime with high levels of humidity. Results of our data-model approach reveal that that the dominant effect of MIS 13 insolation forcing on the regional vegetation and precipitation regime in SW Iberia is amplified by the relatively large extent of the ice-sheets in high northern latitudes. In qualitative agreement with the pollen-based evidence, model results show that ice-sheet forcing triggers an increase in the SW Iberian tree fraction along with both intensified winter and summer rainfall. We propose that the interactions between ice-sheets and major atmospheric circulation systems may have resulted in the persistent influence of the mid-latitude cells over the SW Iberian region, which led to intensified moisture availability and reduced seasonality, and, in turn, to a pronounced expansion of the temperate forest.

How to cite: Oliveira, D., Desprat, S., Yin, Q., Rodrigues, T., Naughton, F., Trigo, R., Su, Q., Grimalt, J. O., Alonso-Garcia, M., Voelker, A. H. L., Abrantes, F., and Sánchez Goñi, M. F.: Enhanced humidity in SW Iberia driven by the combination of insolation and ice-sheet forcing during MIS 13 interglacial, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-11408,, 2021.

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