Holocene hydrological changes in the Eastern Equatorial Pacific
Résumé
The Eastern Equatorial Paci c region is marked by extreme latitudinal gradients in sea surface temperature and precipitation regimes, varying from the hyperhumid warm pool region North of Panama Basin to the hyperarid coast of southern Ecuador and northern Peru. In between those two regions lies a fresh pool, with the lowest mean and strongest seasonal cycle of sea surface salinity. The fresh pool building and erosion at the seasonal and interannual timescales are associated with changes in atmospheric circulation that cannot be easily tracked back in time. Yet, major changes in the central American monsoon intensity and in the El Niño/Southern Oscillation occurred during the Holocene, but it is still unclear if both climate phenomena have varied independantly or if they were intrinsically tied to each other. We will present preliminary results of a multiproxy study performed on a latitudinal transect of marine sediment cores to track changes in riverine runo and hydrological parameters such as sea surface temperature and salinity during the Holocene. Those results will allow re ning how the fresh pool dynamically responds to regional ocean-atmosphere-land interactions under natural climate variability.
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