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GLOBAL CLIMATE AND ATMOSPHERIC CARBON DIOXIDE :ROLE OF CIRCULATION

Objective

TO DETERMINE THE ROLE OF OCEANIC CIRCULATION IN CLIMATE.

IN THIS MULTINATIONAL PROJECT WE WOULD FOCUS ON THE ACQUISITION OF FORAMINIFERAL ISOTODIC DATA AND QUANTITATIVE MICROPALEONTOLOGY IN SEDIMENT CORES FROM THE HIGH LATITUDES OF BOTH HEMISPHERES. THE MOST IMPORTANT DATA WILL COME FROM VERTICAL TRANSECTS OF CORES IN THE FAR NORTHERN ATLANTIC (WHICH IS THE MAJOR SOURCE OF DEEP WATER) AND IN THE SOUTHERN OCEAN (WHERE DEEP WATER IS RECYCLED AND EXPORTED TO THE MAJOR OCEAN BASINS). IT WILL ALSO BE ESSENTIAL TO GENERATE DATA FROM DEPTH TRANSECTS IN THE NORTH PACIFIC, SINCE THE OCEAN DEEP CIRCULATION CAN ONLY BE MEANINGFULLY EXAMINED IN TERMS OF THE WHOLE OCEAN. FOR THE NORTHERMOST ATLANTIC, A SUITE OF CORES HAS ALREADY BEEN IDENTIFIED THAT REQUIRE WORK AND THREE OF THESE WILL BE ANALYZED IN DETAILS. FOR THE NORTH PACIFIC THERE ARE FEW POSSIBLE LOCATIONS BECAUSE OF THE PROBLEM THAT MOST OF THE NORTH PACIFIC IS TOO DEEP FOR THE PRESERVATION OF CARBONATE. SEVERAL CORES HAVE BEEN LOCATED THAT MAY FULFILL OUR REQUIREMENTS AND BECAUSE OF THEIR CRITICAL IMPORTANCE THESE WILL BE ANALYZED FOR SEVERAL BENTHIC SPECIES. FOUR CORES FROM THE SOUTHERN OCEAN WILL COMPLETE OUR COVERAGE FOR THE SOUTHERN HEMISPHERE.

THE GIF TANDETRON WILL BE USED TO PROVIDE AMS C-14 DATING FOR THE MOST IMPORTANT CORES, SELECTED AS THE STABLE ISOTOPE ANALYSIS IS COMPLETED. FOUR CORES WILL AT LEAST BE RUN FOR THIS PROJECT IN ORDER TO PROVIDE A RADIOMETRIC TIME SCALE FOR THE LAST 40,000 YEARS AND IMPROVE OUR KNOWLEDGE FOR THE RESIDENCE TIME OF THE OCEAN DEEP WATERS UNDER CLIMATIC CONDITIONS DIFFERENT FROM THOSE OF TODAY.
THE DATA FROM THESE FOUR LABORATORIES WILL CONSTITUTE AN UNIQUE DATA BASE TO COMPARE WITH THE SIMULATIONS PROVIDED BY THE HAMBURG OCEAN GCM.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Centre National de la Recherche Scientifique (CNRS)
Address
Avenue De La Terrasse
91190 Gif-sur-yvette
France

Participants (2)

MAX-PLANCK-INSTITUT F METEOROLOGIE
UNIV OF CAMBRIDGE