Synthesis & Modeling Project
Scott C. Doney
The impact of interannual variability on air-sea CO2 fluxes and oceanic dissolved inorganic carbon fields: numerical experiments in the NCAR CSM Ocean Model (NCOM)

NOAA/DOE OACES, 36 months

PROJECT DESCRIPTION: The preliminary analysis of the WOCE/JGOFS global ocean carbon survey has contributed greatly to an improved understanding of the mean and perturbed state of the ocean carbon cycle.  The global carbon data set and associated new data analysis techniques have helped to clarify among other issues the air-sea CO2 flux fields, the natural dissolved inorganic carbon background distributions, and the long-term uptake patterns of anthropogenic carbon.  A decade long, one-time global survey, however, is less useful for constraining the temporal variability of the ocean, for which we will have to turn to more directed measurement programs and numerical models.  Here, I propose to evaluate the impact of interannual climate variability on the ocean carbon system using a state of the art numerical global ocean circulation model, the NCAR CSM Ocean Model (NCOM), driven with synoptic atmospheric forcing data sets either from the NCEP reanalysis (1957-1996) or the coupled NCAR Climate System Model.

The analysis of the resulting model variability in the air-sea CO2 flux and subsurface dissolved inorganic carbon distribution will be focused on two related questions: 

  1. what is the oceanic contribution to the observed variability in the atmospheric CO2 growth rate?, and 
  2. what type of sampling strategy is needed to quantify the long-term uptake of anthropogenic carbon given the natural background variability? 
Particular emphasis will be given to examining the physical and biological mechanisms governing variability in the model and their relevance to the real ocean.  Oceanic and atmospheric carbon observations will be used extensively to validate both the mean state and variability of the ocean carbon model in collaboration with a number of co-investigators (D. Schimel, NCAR; I. Fung, UC Berkeley; R. Wanninkhof, NOAA/AOML).  This study will provide also a framework for interpreting the WOCE/JGOFS global CO2 survey and designing optimal future sampling networks.


DATA: Model results of 1-D global mixed layer depth ecosystem model, by Keith Moore and Scott Doney
PUBLICATIONS: Moore, J. Keith, Scott C. Doney, Joan A. Kleypas, David M. Glover, and Inez Y. Fung. 2002. An intermediate complexity marine ecosystem model for the global domain. DSR II 49 (1-3):403-462.

Moore, J. Keith, Scott C. Doney, David M. Glover, and Inez Y. Fung.  2002. Iron cycling and nutrient limitation patterns in surface waters of the world ocean. DSR II 49 (1-3): 463-508.

RELATED PROJECTS: - no related projects listed -


Scott Doney
Climate and Global Dynamics
National Center for Atmospheric Research
P.O. Box 3000
Boulder, CO 80307
tel: (303) 497-1639
fax: (303) 497-1700