Seasonal dynamics of sea surface salinity off Panama: The Far Eastern Pacific fresh pool

Type Article
Date 2012-04
Language English
Author(s) Alory Gael1, Maes Christophe2, Delcroix Thierry2, Reul NicolasORCID3, Illig Serena2, 4
Affiliation(s) 1 : Univ Toulouse, LEGOS, OMP, CNAP, F-31400 Toulouse, France.
2 : IRD, Univ Toulouse, LEGOS, F-31400 Toulouse, France.
3 : IFREMER, LOS, F-29280 Plouzane, France.
4 : IMARPE, Callao, Peru.
Source Journal Of Geophysical Research-oceans (0148-0227) (Amer Geophysical Union), 2012-04 , Vol. 117 , P. -
DOI 10.1029/2011JC007802
WOS© Times Cited 63
Abstract The freshest surface waters in the tropical Pacific are found at its eastern boundary. Using in situ observations, we depict the quasi-permanent presence of a far eastern Pacific fresh pool with Sea Surface Salinity (SSS) lower than 33, which is confined between Panama's west coast and 85W in December and extends westward to 95W in April. Strong SSS fronts are found at the outer edge of this fresh pool. We investigate the seasonal dynamics of the fresh pool using complementary satellite wind, rain, sea level and in situ oceanic current data at the surface, along with hydrographic profiles. The fresh pool appears off Panama due to the strong summer rains associated with the northward migration of the ITCZ over Central America in June. During the second half of the year, the eastward-flowing North Equatorial Counter Current keeps it trapped to the coast and strengthens the SSS front on its western edge. During winter, as the ITCZ moves southward, the north-easterly Panama gap wind creates a south-westward jet-like current in its path with a dipole of Ekman pumping/eddies on its flanks. As a result, upwelling in the Panama Bight brings to the surface cold and salty waters which erode the fresh pool on its eastern side while both the jet current and the enhanced South Equatorial Current stretch the fresh pool westward until it nearly disappears in May. New SMOS satellite SSS data proves able to capture the main seasonal features of the fresh pool and monitor its spatial extent.
Full Text
File Pages Size Access
Publisher's official version 13 2 MB Open access
Top of the page