A Time-Splitting Scheme for the Elastic Equations Incorporating Second-Order Runge–Kutta Time Differencing

Louis J. Wicker Department of Meteorology, Texas A&M University, College Station, Texas

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William C. Skamarock National Center for Atmospheric Research,* Boulder, Colorado

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Abstract

A forward-in-time splitting method for integrating the elastic equations is presented. A second-order Runge–Kutta time integrator (RK2) for the large-time-step integration is combined with the forward–backward scheme in a manner similar to the Klemp and Wilhelmson method. The new scheme produces fully second-order-accurate integrations for advection and gravity wave propagation. The RK2 scheme uses upwind discretizations for the advection terms and is easily combined with standard vertically semi-implicit techniques so as to improve computational efficiency when the grid aspect ratio becomes large. A stability analysis of the RK2 split-explicit scheme shows that it is stable for a wide range of advective and acoustic wave Courant numbers.

The RK2 time-split scheme is used in a full-physics nonhydrostatic compressible cloud model. The implicit damping properties associated with the RK2’s third-order horizontal differencing allows for a significant reduction in the value of horizontal filtering applied to the momentum and pressure fields, while qualitatively the solutions appear to be better resolved than solutions from a leapfrog model.

Corresponding author address: Dr. Louis J. Wicker, 1204 Eller O&M Bldg., College Station, TX 77843-3150.

Abstract

A forward-in-time splitting method for integrating the elastic equations is presented. A second-order Runge–Kutta time integrator (RK2) for the large-time-step integration is combined with the forward–backward scheme in a manner similar to the Klemp and Wilhelmson method. The new scheme produces fully second-order-accurate integrations for advection and gravity wave propagation. The RK2 scheme uses upwind discretizations for the advection terms and is easily combined with standard vertically semi-implicit techniques so as to improve computational efficiency when the grid aspect ratio becomes large. A stability analysis of the RK2 split-explicit scheme shows that it is stable for a wide range of advective and acoustic wave Courant numbers.

The RK2 time-split scheme is used in a full-physics nonhydrostatic compressible cloud model. The implicit damping properties associated with the RK2’s third-order horizontal differencing allows for a significant reduction in the value of horizontal filtering applied to the momentum and pressure fields, while qualitatively the solutions appear to be better resolved than solutions from a leapfrog model.

Corresponding author address: Dr. Louis J. Wicker, 1204 Eller O&M Bldg., College Station, TX 77843-3150.

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  • Carpenter, R. L., Jr., K. K. Droegemeier, P. R. Woodward, and C. E. Hane, 1990: Application of the piecewise parabolic method (PPM) to meteorological modeling. Mon. Wea. Rev.,118, 586–612.

  • Haltiner, G. J., and R. T. Williams, 1980: Numerical Prediction and Dynamic Meteorology. John Wiley and Sons, 447 pp.

  • Hundsdorfer, W., B. Koren, M. van Loon, and J. G. Verwer, 1995: A positive finite difference advection scheme. J. Comput. Phys.,117, 35–46.

  • Klemp, J. B., and R. B. Wilhelmson, 1978: The simulation of three-dimensional convective storm dynamics. J. Atmos. Sci.,35, 1070–1096.

  • Marchuk, G. I., 1974: Numerical Methods in Weather Prediction. Academic Press, 227 pp.

  • Mesinger, F. M., 1977: Forward–backward scheme, and its use in a limited area model. Contrib. Atmos. Phys.,50, 200–210.

  • Pielke, R. A., 1984: Mesoscale Meteorological Modeling. Academic Press, 612 pp.

  • Press, W. H., B. F. Flannery, S. A. Teukolsky, and W. T. Vetterling, 1986: Numerical Recipes. Cambridge University Press, 818 pp.

  • Skamarock, W. C., and J. B. Klemp, 1992: The stability of time-split numerical methods for the hydrostatic and nonhydrostatic elastic equations. Mon. Wea. Rev.,120, 2109–2127.

  • ——, and ——, 1994: Efficiency and accuracy of the Klemp–Wilhelmson time-splitting technique. Mon. Wea. Rev.,122, 2623–2630.

  • Smolarkiewicz, P. K., 1984: A fully multidimensional positive definite advective transport algorithm with small implicit diffusion. J. Comput. Phys.,54, 325–362.

  • Tremback, C. J., J. Powell, W. R. Cotton, and R. A. Pielke, 1987: The forward-in-time upstream advection scheme: Extension to higher orders. Mon. Wea. Rev.,115, 540–555.

  • Wicker, L. J., and R. B. Wilhelmson, 1995: Simulation and analysis of tornado development and decay within a three-dimensional supercell thunderstorm. J. Atmos Sci.,52, 2675–2703.

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