Peru-Chile upwelling dynamics under climate change

VERA OERDER , Francois Colas, Vincent Echevin, Francis Codron, Jorge Tam, Ali Belmadani

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

Abstract

The consequences of global warming on the Peru-Chile Current System (PCCS) ocean circulation are examined with a high-resolution, eddy-resolving regional oceanic model. We performed a dynamical downscaling of climate scenarios from the IPSL-CM4 Coupled General Circulation Model (CGCM), corresponding to various levels of CO2 concentrations in the atmosphere. High-resolution atmospheric forcing for the regional ocean model are obtained from the IPSL atmospheric model run on a stretched grid with increased horizontal resolution in the PCCS region. When comparing future scenarios to preindustrial (PI) conditions, the circulation along the Peru and Chile coasts is strongly modified by changes in surface winds and increased stratification caused by the regional warming. While the coastal poleward undercurrent is intensified, the surface equatorial coastal jet shoals and the nearshore mesoscale activity are reinforced. Reduction in alongshore wind stress and nearshore wind stress curl drive a year-round reduction in upwelling intensity off Peru. Modifications in geostrophic circulation mitigate this upwelling decrease in late austral summer. The depth of the upwelling source waters becomes shallower in warmer conditions, which may have a major impact on the system's biological productivity.

Original languageEnglish
Pages (from-to)1152-1172
Number of pages21
JournalJournal of Geophysical Research: Oceans
Volume120
Issue number2
DOIs
StatePublished - 1 Jan 2015

Keywords

  • dynamical downscaling
  • Peru-Chile current system
  • regional climate change
  • upwelling dynamics

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