The position of the gulf stream during quaternary glaciations.


Journal Article

Ocean general circulation theories predict that the position of the boundary between subtropical and subpolar gyres (and therefore the position of the Gulf Stream-North Atlantic Current system and the subpolar-subtropical front) is set by the line of zero "Ekman pumping," where there is no convergence or divergence of water in the directly wind-forced surface layer of the ocean. In the present-day North Atlantic Ocean this line runs southwest to northeast, from off the Carolinas to off Ireland. However, during the last ice age (18,000 years ago) the subpolar-subtropical boundary ran more zonally, directly toward Gibraltar. A numerical atmospheric general circulation model indicates that the field of Ekman pumping 18,000 years ago was modified by the presence of a continental ice cap more than 3 kilometers thick such that the line of zero Ekman pumping overlaid the paleogyre boundary. These results demonstrate that the presence of a thick continental ice sheet could have caused changes in sea surface temperatures in the North Atlantic during Quaternary glaciations by altering wind patterns.

Full Text

Duke Authors

Cited Authors

  • Keffer, T; Martinson, DG; Corliss, BH

Published Date

  • July 1988

Published In

Volume / Issue

  • 241 / 4864

Start / End Page

  • 440 - 442

PubMed ID

  • 17792608

Pubmed Central ID

  • 17792608

Electronic International Standard Serial Number (EISSN)

  • 1095-9203

International Standard Serial Number (ISSN)

  • 0036-8075

Digital Object Identifier (DOI)

  • 10.1126/science.241.4864.440


  • eng