P1.46
CO2outgassing continued in an upwelling area off northern Chile during the development phase of El Niņo 97-98
Rodrigo Torres-Saavedra, Univ. of Göteborg, Göteborg, Sweden; and D. Turner and J. A. Rutllant
continues. High positive SST and sea level anomalies observed off northern Chile since approximately April-May 1997 indicated the onset of El Niņo 97-98 in this region. A survey carried out off northern Chile at ca. 23.5°S during July 1997 (austral-winter) showed that the entire water column that feeds the coastal upwelling was anomalously warm and salty compared with non-El Niņo winters. Vertical distributions of pH, total alkalinity, calculated fCO2 (fugacity of CO2) and O2 suggested that below 20m depth the coastal water column was more oxygenated and with lower fCO2 than the colder water that occupied this stratum during the non-El Niņo years (e.g. July 1989). Nevertheless the entire water column remained largely CO2 supersaturated during July 1997.
During the study period as well as during others winters (i.e. 1972, 1983) when the sea temperature anomalies were strongly positive (> +2°C) the main portion of the oxycline remained over 100m depth, consequently low oxygen and CO2 rich water (oxygen-poor waters are invariably CO2 supersaturated) can reach the surface due events of enhanced upwelling forcing. In fact under active upwelling during july 1997 we found coastal fCO2 levels between 400-600ĩatm. We conclude that the coastal CO2 outgassing continues during El Niņo periods as long as coastal upwelling
Poster Session 1, Oceanography: Satellite Data, Applied Meteorology, Atmospheric Chemistry, Urban Climate
Saturday, 3 April 1999, 1:15 PM-3:00 PM
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