• Aart, E., and J. Korst, 1990: Simulated Annealing and Boltzmann Machine. John Wiley and Sons, 272 pp.

  • Anderson, J. L., 1992: Barotropic stationary states and persistent anomalies in the atmosphere. J. Atmos. Sci.,49, 1709–1722.

  • Barnston, A. G., and R. E. Livezey, 1987: Classification, seasonality, and persistence of low-frequency atmospheric circulation patterns. Mon. Wea. Rev.,115, 1083–1126.

  • Berry, F. A., E. Bollay, and N. R. Beers, 1973: Handbook of Meteorology. McGraw-Hill, 1068 pp.

  • Branstator, G., 1987: A striking example of the atmosphere’s leading travelling pattern. J. Atmos. Sci.,44, 2310–2323.

  • ——, and J. D. Opsteegh, 1989: Free solutions of the barotropic vorticity equation. J. Atmos. Sci.,46, 1799–1814.

  • Charney, J. G., and J. G. Devore, 1979: Multiple flow equilibria in the atmosphere and blocking. J. Atmos. Sci.,36, 1205–1216.

  • Dole, R. M., 1986: Persistent anomalies of the extratropical Northern Hemisphere wintertime circulation: Structure. Mon. Wea. Rev.,114, 178–207.

  • ——, and D. N. Gordon, 1983: Persistent anomalies of the extratropical Northern Hemisphere winter circulation: Geophysical distribution and regional persistent characteristics. Mon. Wea. Rev.,111, 1567–1586.

  • Duchon, C. E., 1979: Lanczos filtering in one and two dimensions. J. Appl. Meteor.,18, 1016–1022.

  • Everitt, B. S., and D. J. Hand, 1981: Finite Mixture Analysis. Chapmann and Hall, 143 pp.

  • Frederiksen, J. S., 1992: Towards a unified instability theory of large-scale atmospheric disturbances. Trends Atmos. Sci.,1, 239–261.

  • Haines, K., and J. Marshall, 1987: Eddy-forced coherent structures as a prototype of atmospheric blocking. Quart. J. Roy. Meteor. Soc.,113, 681–704.

  • ——, and A. Hannachi, 1995: Weather regimes in the Pacific from a GCM. J. Atmos. Sci.,52, 2444–2462.

  • Haltiner, J. G., and R. T. Williams, 1980: Numerical Prediction and Dynamic Meteorology. John Wiley and Sons, 477 pp.

  • Hannachi, A., and B. Legras, 1995: Simulated annealing and weather regimes classification. Tellus,47A, 955–973.

  • Hansen, A. R., 1986: Observational characteristics of atmospheric planetary waves with bimodal amplitude distributions. Advances in Geophysics, Vol. 29, Academic Press, 101–133.

  • ——, and A. Sutera, 1986: On the probability density distribution of large-scale atmospheric wave amplitude. J. Atmos. Sci.,43, 3250–3265.

  • Horel, J. D., 1981: A rotated principal component analysis of the interannual variability of the Northern Hemisphere 500 mb height field. Mon. Wea. Rev.,109, 2080–2092.

  • Hoskins, B. J., and D. J. Karoly, 1981: The steady linear response of a spherical atmosphere to thermal and orographic forcing. J. Atmos. Sci.,38, 1179–1196.

  • ——, I. N. James, and G. H. White, 1983: The shape, propagation and mean-flow interaction of large-scale weather systems. J. Atmos. Sci.,40, 1595–1612.

  • Illari, L., 1984: A diagnostic study of the potential vorticity in a warm blocking anticyclone. J. Atmos. Sci.,41, 3518–3526.

  • Kimoto, M., M. Mukougawa, and S. Yoden, 1992: Medium-range forecast skill variation and blocking transition: A case study. Mon. Wea. Rev.,120, 1616–1627.

  • Legras, B., and M. Ghil, 1985: Persistent anomalies, blocking and variations in atmospheric predictability. J. Atmos. Sci.,42, 433–471.

  • Lichtenberg, A. J., and M. A. Lieberman, 1983: Regular and Stochastic Motion. Springer-Verlag, 499 pp.

  • Lorenz, E. N., 1963: Deterministic nonperiodic flow. J. Atmos. Sci.,20, 130–141.

  • ——, 1965: A study of the predictability of a 28-variable atmospheric model. Tellus,17, 321–333.

  • Marshall, J. C., and F. Molteni, 1993: Toward a dynamical understanding of planetary-scale flow regimes. J. Atmos. Sci.,50, 1792–1818.

  • Michelangeli, P. A., R. Vautard, and B. Legras, 1995: Weather regimes: Recurrence and quasi-stationarity. J. Atmos. Sci.,52, 1237–1256.

  • Mo, K. C., and M. Ghil, 1987: Statistics and dynamics of persistent anomalies. J. Atmos. Sci.,44, 877–901.

  • ——, and ——, 1988: Cluster analysis of multiple planetary flow regimes. J. Geophys. Res.,93, 927–952.

  • Molteni, F., S. Sutera, and N. Tronci, 1988: The EOFs of the geopotential eddies at 500 mb in winter and their probability density distributions. J. Atmos. Sci.,45, 3063–3080.

  • ——, S. Tibaldi, and T. N. Palmer, 1990: Regimes in the wintertime circulation over northern extratropics. I: Observational evidence. Quart. J. Roy. Meteor. Soc.,116, 31–67.

  • Mukougawa, H., 1987: Instability of topographically forced Rossby waves in a two layer model. J. Meteor. Soc. Japan,65, 13–25.

  • ——, 1988: A dynamical model of “quasi-stationary” states in large-scale atmospheric motions. J. Atmos. Sci.,45, 2868–2888.

  • Namias, J., 1950: The index cycle and its role in the general circulation. J. Meteor.,7, 130–139.

  • ——, 1964: Seasonal persistence and recurrence of European blocking during 1958–1960. Tellus,16, 94–407.

  • Neven, E. C., 1994: Baroclinic modons on a sphere. J. Atmos. Sci.,51, 1447–1464.

  • Nitsche, G., J. M. Wallace, and C. Kooperberg, 1994: Is there evidence of multiple equilibria in planetary wave amplitude statistics? J. Atmos. Sci.,51, 314–322.

  • Palmer, T. N., 1988: Medium and extended range predictability and stability of the Pacific/North American mode. Quart. J. Roy. Meteor. Soc.,114, 691–713.

  • ——, and D. L. T. Anderson, 1994: The prospects for seasonal forecasting—A review paper. Quart. J. Roy. Meteor. Soc.,120, 755–793.

  • Rex, D., 1950: Blocking action in the middle troposphere and its effect upon regional climate. Tellus,2, 196–211.

  • Shutts, G. J., 1983: The propagation of eddies in diffluent jet streams: Eddy forcing of blocking flow fields. Quart. J. Roy. Meteor. Soc.,109, 737–761.

  • Silverman, B. W, 1986: Density Estimation for Statistics and Data Analysis. Chapman and Hall, 175 pp.

  • Simmons, A. J., J. M. Wallace, and G. W. Branstator, 1983: Barotropic wave propagation and instability, and atmospheric teleconnection patterns. J. Atmos. Sci.,40, 1363–1392.

  • Thuburn, J., 1991: Data sampling strategies for general circulation models. Quart. J. Roy. Meteor. Soc.,117, 385–397.

  • Tung, K. K., and A. J. Rosenthal, 1985: Theories of multiple equilibria—A critical reexamination. Part I: Barotropic models. J. Atmos. Sci.,42, 2804–2819.

  • Vautard, R., 1990: Multiple weather regimes over the North Atlantic: Analysis of precursors and successors. Mon. Wea. Rev.,118, 2056–2081.

  • ——, and B. Legras, 1988: On the source of low frequency variability. Part II: Nonlinear equilibration of weather regimes. J. Atmos. Sci.,45, 2845–2867.

  • Wallace, J. M., and D. S. Gutzler, 1981: Teleconnections in the geopotential height field during the Northern Hemisphere winter. Mon. Wea. Rev.,109, 784–812.

  • Wiin-Nielsen, A., 1979: Steady states and stability properties of a low order barotropic system with forcing and dissipation. Tellus,31, 375–386.

  • Wolfe, J. H., 1970: Pattern clustering by multivariate mixture analysis. Multiv. Behav. Res.,5, 329–350.

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Low-Frequency Variability in a GCM: Three-Dimensional Flow Regimes and Their Dynamics

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  • 1 Department of Meteorology, University of Edinburgh, Edinburgh, United Kingdom
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Abstract

General circulation models (GCMs) can be used to develop diagnostics for identifying weather regimes. The author has looked for three-dimensional (3D) weather regimes associated with a 10-yr run of the U.K. UGAMP GCM with perpetual January boundary conditions; 3D low-pass empirical orthogonal functions (EOFs), using both the 500- and 250-mb streamfunctions (ψ) have been computed. These EOFs provide a low-order phase space in which weather regimes are studied.

The technique here is an extension to 3D of that of . They found, within the 500-mb ψ EOF phase space, two local minima of area-averaged ψ-tendency (based on barotropic vorticity dynamics), which were identified as ±Pacific–North America (PNA). In this work, the author demands that both the flow and its tendency be within the phase space spanned by the 3D EOFs. The streamfunction tendency is computed from the two-level quasigeostrophic potential vorticity equation and projected onto the EOF phase space. This projection produces a finite dynamical system whose singular points are identified as the quasi-stationary states. Two blocking solutions and one zonal solution are found over the Pacific. The first blocking solution is closer to the west coast of North America than the other blocking, which is shifted slightly westward and has a larger scale, rather similar to the +PNA pattern, indicating that blocking over the Pacific may have two phases in the model. Further investigation of the GCM trajectory within the EOF phase space using a mixture analysis shows the existence of realistic three-dimensional weather regimes similar to the singular points. The same solutions were found when the transient eddy contributions to the climatological quasigeostrophic potential vorticity budget were included. It is also shown that this extended technique allows a direct study of the stability of these quasi-stationary states and helps in drawing transition pictures and determining the transition times between them.

Corresponding author address: Dr. A. Hannachi, Dept. of Meteorology, University of Edinburgh, James Clerk Maxwell Building, King’s Buildings, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom.

Abstract

General circulation models (GCMs) can be used to develop diagnostics for identifying weather regimes. The author has looked for three-dimensional (3D) weather regimes associated with a 10-yr run of the U.K. UGAMP GCM with perpetual January boundary conditions; 3D low-pass empirical orthogonal functions (EOFs), using both the 500- and 250-mb streamfunctions (ψ) have been computed. These EOFs provide a low-order phase space in which weather regimes are studied.

The technique here is an extension to 3D of that of . They found, within the 500-mb ψ EOF phase space, two local minima of area-averaged ψ-tendency (based on barotropic vorticity dynamics), which were identified as ±Pacific–North America (PNA). In this work, the author demands that both the flow and its tendency be within the phase space spanned by the 3D EOFs. The streamfunction tendency is computed from the two-level quasigeostrophic potential vorticity equation and projected onto the EOF phase space. This projection produces a finite dynamical system whose singular points are identified as the quasi-stationary states. Two blocking solutions and one zonal solution are found over the Pacific. The first blocking solution is closer to the west coast of North America than the other blocking, which is shifted slightly westward and has a larger scale, rather similar to the +PNA pattern, indicating that blocking over the Pacific may have two phases in the model. Further investigation of the GCM trajectory within the EOF phase space using a mixture analysis shows the existence of realistic three-dimensional weather regimes similar to the singular points. The same solutions were found when the transient eddy contributions to the climatological quasigeostrophic potential vorticity budget were included. It is also shown that this extended technique allows a direct study of the stability of these quasi-stationary states and helps in drawing transition pictures and determining the transition times between them.

Corresponding author address: Dr. A. Hannachi, Dept. of Meteorology, University of Edinburgh, James Clerk Maxwell Building, King’s Buildings, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom.

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