A note on using the accelerated convergence method in climate models

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Wang, Dailin (2011)

Application of the accelerated convergence (or asynchronous integration) method of Bryan(1984) to climate problems with time-dependent forcing is investigated using an ocean generalcirculation model (GCM), with an idealized box ocean and forced with an idealized seasonalrestoring surface temperature. Numerical experiments consist of a control experiment, which isintegrated synchronously for 9000 years, and 2 experiments with asynchronous integration, onewith depth dependent acceleration and one with depth independent acceleration. The latter 2cases 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 newequilibrium 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 theearly stage of synchronous adjustment by about 0.01°C. So for practical purposes, 50 years ofsynchronous integration beyond asynchronous equilibrium is sufficient. A simple interpretationof the accelerated convergence method of Bryan is also presented.DOI: 10.1034/j.1600-0870.2001.01134.x
  • References (8)

    Bryan, K. 1984. Accelerating the convergence to equilibrium of ocean-climate models. J. Phys. Oceanogr. 14, 666-673.

    Courant, R., Friedrichs, K. O. and Lewy, H. 1928. U¨ber die partiellen Differenzengleichungen der mathematischen Physik. Math. Ann. 100, 32.

    Cox, M. D. 1984. Geophysical Fluid Dynamics L aboratory T echnical Report no. 1, Princeton.

    Danabasoglu, G, McWilliams, J. C. and Large, W. G. 1996. Approach to equilibrium in accelerated global oceanic models. J. Climate 9, 1092-1110.

    Levitus, S. 1982. Climatological atlas of the world's oceans. NOAA Prof. Paper No. 13, US Govt. Printing Office.

    Marotzke, J. 1991. Influence of convective adjustment on the stability of the thermohaline circulation. J. Phys. Oceanogr. 21, 903-907.

    Semtner, A. J. 1974. An oceanic general circulation model with bottom topography. Tech. Rep. no. 9, Department of Meteorology, University of California, Los Angeles, CA, 99 pp.

    Wang, D. 1993. Modeling deep equatorial circulation. Ph.D. thesis, University of Hawaii at Manoa, 157 pp.

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