HR: 13:40h
AN: OS33D-01    [Abstracts]
TI: Strength and Trends in Modern Oceanic Fluxes of Mass and Heat
AU: * Wunsch, C
EM: cwunsch@mit.edu
AF: Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences Room 54-1524, Cambridge, MA 02130 United States
AU: Heimbach, P
EM: heimbach@mit.edu
AF: Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences Room 54-1524, Cambridge, MA 02130 United States
AB: A one degree, 23 layer general circulation model has been least-squares fit to approximately 410 million direct oceanic observations in the interval 1992-2004 (ECCO Group). The model/data misfits are generally within the estimated a priori error bars. Data constraints include mean and time-varying altimetric data, CTD sections, the ARGO float temperature and salinity profiles, hydrographic climatologies, NCEP/NCAR reanalysis surface fluxes, XBTs, etc. One can therefore estimate in a dynamically consistent way the time-varying ocean circulation over this period including both its mean values, trends, and higher frequency fluctuations and assert that the result is also consistent with most observations. Apart from the Southern Ocean, only slight and marginally statistically significant trends can be found in any of the net mass or heat fluxes anywhere, including the North Atlantic, although as expected, redistributions of water mass fluxes do occur on all time scales. As with any use of a numerical model, inferences are only as reliable as the model itself. Here the overall fit to strongly constraining observations and the general insensitivity to perturbations in weights suggests a robust result, but model resolution and subgrid scale parameterizations remain concerns.
UR: http://ocean.mit.edu/~cwunsch
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 4512 Currents
DE: 4532 General circulation (1218, 1222)
SC: Ocean Sciences [OS]
MN: Fall Meeting 2005