Many thanks are due to the predictability group at KNMI for a pleasant and stimulating atmosphere. I am grateful to Theo Opsteegh, head of this group, for his continuous support and help during this research.
Achatz, U., G. Schmitz, and K. M. Greisiger, 1995: Principal interaction patterns in baroclinic wave cycles. J. Atmos. Sci.,52, 3201–3213.
Faller, A. J., and C. E. Schemm, 1977: Statistical corrections to numerical prediction equations. Mon. Wea. Rev.,105, 37–56.
Hasselman, K., 1988: PIPS and POPS: The reduction of complex dynamical systems using principal interaction and oscillation patterns. J. Geophys. Res.,93 (D9), 11 015–11 021.
Illari, L., and J. C. Marshall, 1983: On the interpretation of eddy fluxes during a blocking period. J. Atmos. Sci.,40, 2232–2242.
Kwasniok, F., 1996: The reduction of complex dynamical systems using principal interactions patterns. Physica D,92, 28–60.
Leith, C. E., 1978: Objective methods for weather prediction. Annu. Rev. Fluid Mech.,10, 107–128.
Machenhauer, B., 1991: Spectral methods. Proc. Numerical Methods in Atmospheric Models, Reading, United Kingdom, European Centre for Medium-Range Weather Forecasts, 3–85.
MacVean, M. K., 1983: The effects of horizontal diffusion on baroclinic development in a spectral model. Quart. J. Roy. Meteor. Soc.,109, 771–783.
Press, W. H., B. P. Flannery, S. A. Teukolsky, and W. T. Vetterling, 1986: Numerical Recipes—The Art of Scientific Computing. Cambridge University Press, 818 pp.
Selten, F. M., 1993: Toward an optimal description of atmospheric flow. J. Atmos. Sci.,50, 861–877.
——, 1995: An efficient description of the dynamics of barotropic flow. J. Atmos. Sci.,52, 915–936.