Premium
P eru‐ C hile upwelling dynamics under climate change
Author(s) -
Oerder Véra,
Colas Francois,
Echevin Vincent,
Codron Francis,
Tam Jorge,
Belmadani Ali
Publication year - 2015
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2014jc010299
Subject(s) - upwelling , climatology , environmental science , wind stress , mesoscale meteorology , geostrophic wind , oceanography , forcing (mathematics) , climate model , downscaling , ocean current , atmospheric sciences , climate change , geology
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 CO 2 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.