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A note on using the accelerated convergence method in climate models


Dailin Wang

International Pacific Research Center*, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, 2525 Correa Road, Honolulu, Hawaii 96822, US
About Dailin
International Pacific Research Centre is partly sponsored by the Frontier Research System for Global Change.
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Application of the accelerated convergence (or asynchronous integration) method of Bryan (1984) to climate problems with time-dependent forcing is investigated using an ocean general circulation model (GCM), with an idealized box ocean and forced with an idealized seasonal restoring surface temperature. Numerical experiments consist of a control experiment, which is integrated synchronously for 9000 years, and 2 experiments with asynchronous integration, one with depth dependent acceleration and one with depth independent acceleration. The latter 2 cases were integrated synchronously for 9000 years after asynchronous equilibria are reached. It is found that a few thousand years of synchronous integration is needed to reach a new equilibrium after asynchronous equilibrium is obtained, consistent with a scaling argument. However, at the new equilibrium, temperature in the deep ocean only differs from that of the early stage of synchronous adjustment by about 0.01°C. So for practical purposes, 50 years of synchronous integration beyond asynchronous equilibrium is sufficient. A simple interpretation of the accelerated convergence method of Bryan is also presented.

How to Cite: Wang, D., 2001. A note on using the accelerated convergence method in climate models. Tellus A: Dynamic Meteorology and Oceanography, 53(1), pp.27–34. DOI:
  Published on 01 Jan 2001
 Accepted on 10 Jul 2000            Submitted on 6 Sep 1999


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