Performance of an upper-ocean model coupled to an atmospheric GCM: preliminary results. Vol. 2
A global dynamical model of the upper ocean and sea ice is coupled to the OSU atmospheric general circulation model. Preliminary results are described from a 16-month simulation with seasonally-varying insolation, and compared with both observations and the results from two earlier experiments with simpler upper-ocean models. The present ocean model consists of two vertically homogeneous layers of variable thickness: the upper layer represents the well-mixed layer and can entrain or detrain fluid locally with the lower layer, as in standard mixed-layer models. The second layer typically has thicknesses of approx.100 to approx.400 meters and crudely represents the seasonal thermocline and the part of the main thermocline involved in the subtropical gyres; it rests immiscibly on deep water of no motion where the density contrast is prescribed. Horizontal advection is predicted in both layers by the primitive momentum equations. Sea ice can form if the upper-layer temperature (SST) drops to freezing, after which the local ice thickness is predicted thermo-dynamically with ice dynamics neglected. The 16-month simulation is started from relatively realistic conditions obtained by spinning up the atmospheric and oceanic models separately. After several months of the coupled run, errors of up to 4/sup 0/C in the SST appear in the western oceans, probably due to the underestimate of the western boundary currents inherent in coarse-grid oceanic models. Equatorial upwelling and undercurrents are simulated but extend basin-wide, producing SSTs up to 6/sup 0/C too cold in the western equatorial Pacific. The large-scale seasonal variation of sea-ice thickness and extent are fairly realistic. Surface heat fluxes are compared with observations and with an earlier control integration of the atmospheric GCM, in an effort to distinguish between errors in the SST caused by the upper-ocean model and those caused by the atmospheric model. 38 refs., 11 figs.
- Research Organization:
- Oregon State Univ., Corvallis (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5447503
- Report Number(s):
- UCRL-15704-Vol.2; ON: DE85017265
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products. Report No. 31
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CLIMATES
MATHEMATICAL MODELS
SEAS
TEMPERATURE DISTRIBUTION
AIR-WATER INTERACTIONS
BOUNDARY CONDITIONS
COMPUTERIZED SIMULATION
EARTH ATMOSPHERE
ERRORS
GLOBAL ASPECTS
PERFORMANCE
UPWELLING
WATER CURRENTS
CURRENTS
SIMULATION
SURFACE WATERS
520100* - Environment
Aquatic- Basic Studies- (-1989)
500100 - Environment
Atmospheric- Basic Studies- (-1989)