Large Scale Oceanic Circulation and Fluxes of Freshwater, Heat, Nutrients and Oxygen
Abstract
A new, global inversion is used to estimate the large scale oceanic circulation based on the World Ocean Circulation Experiment and JADE hydrographic data. A linear inverse "box" model is used to combine consistently the transoceanic sections. The circulation is geostrophic with an Ekman layer at the surface. Near conservation of mass, salt and top-to-bottom silica is required and, in addition, heat and the phosphate-oxygen combination (170PO4+O2) are conserved in isopycnal layers that are not in contact with the surface. A globally-consistent solution is obtained for the circulation and freshwater flux divergences. A detailed error budget permits calculation of statistical uncertainties, taking into account the temporal oceanic variability. The estimated water mass transports during the WOCE period (1985-1996) are generally similar to previous published estimates. However, differences are found. Noticeably, the inflow of bottom waters into the Pacific Ocean is smaller than most previous estimates. Significant dianeutral diffusivities are found in deep layers, 21 with a global average of 3 plus or minus 1 cm squared/s north of 30 degrees South. Ocean-atmosphere heat fluxes are diagnosed in each regions; nutrient and oxygen divergences are analyzed in light of their respective biogeochemical cycles.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2000
- Accession Number
- ADA384765
Entities
People
- Alexandre Ganachaud
Organizations
- Massachusetts Institute of Technology