Air-sea CO2 flux estimates from two data-constrained ocean models for the NASA Carbon Monitoring Study Flux Pilot Project and their impact on atmospheric CO2 concentration variability
Abstract
The objective of the NASA Carbon Monitoring System (CMS) Surface Carbon Flux Pilot Project is to use NASA observational constraints and state-of-the-art assimilating models to estimate CO2 fluxes between the land, ocean, and atmosphere. Here we describe the two ocean components of this pilot study and evaluate impact of estimated ocean fluxes on the time-evolving atmospheric CO2 concentration. The first ocean component is the NASA Ocean Biogeochemistry Model (NOBM), which is comprised of a biogeochemical processes model, coupled to the Poseidon ocean model, and driven at the surface by the Modern Era Retrospective-analysis for Research and Applications (MERRA). Ocean color data is assimilated using the Ocean-Atmosphere Spectral Irradiance Model (OASIM). The second ocean component is based on a global, eddying physical ocean solution provided by the Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2), which is coupled to the Massachusetts Institute of Technology ecosystem model (Darwin), and to a marine carbon chemistry model. The ECCO2 ocean solution assimilates a variety of satellite and in-situ data, including Jason altimetry, AMSRE-E sea surface temperature, and Argo temperature and salinity profiles. The two CMS ocean components generate independent air-sea CO2 flux estimates and hence provide a means to probe system uncertainties. We document the similarities and differences between the two solutions and compare them to in-situ observations and to the Takahashi air-sea CO2 flux climatology. The two ocean solutions are used to drive two atmospheric carbon chemistry models, GEOS-5 and GEOS-Chem, in order to investigate impact of air-sea CO2 flux variability on atmospheric CO2 concentrations. Preliminary results, available at the time of writing of this abstract, suggest that large-scale biases between the two ocean solutions have a large, measurable impact on atmospheric CO2 variability. Impact of high frequency and wavenumber differences between the two solutions on atmospheric CO2 variability will also be investigated.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.A43H..08B
- Keywords:
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- 0428 BIOGEOSCIENCES / Carbon cycling;
- 3339 ATMOSPHERIC PROCESSES / Ocean/atmosphere interactions;
- 4255 OCEANOGRAPHY: GENERAL / Numerical modeling;
- Data Assimilation