System and method for nesting a nonhydrostatic model in a hydrostatic model

摘要

System and method for adjusting the values of the prognostic variables near the interface between a nonhydrostatic, high resolution model embedded in a hydrostatic, coarser resolution model. The system and method condition the outer domain lateral boundary values to enforce conservation of volume when the variables are interpolated onto the inner domain grid. The conditioning adjusts the baroclinic normal velocities at the open boundaries before interpolation. The system and method also include a relaxation scheme which matches the values of the prognostic variables across a zone near the open boundaries of the submesoscale inner domain to prevent the development of discontinuities, reflections and perimeter currents at the periphery of the inner domain.

主权项

1. An automated method for correcting the baroclinic normal velocity on an inner domain comprising the steps of:
obtaining transport values that are archived by a numerical model during a plurality of forecasts, wherein the numerical model includes an inner grid of the inner domain and an outer grid of an outer domain for representing a plurality of features; bilinearly interpolating the transport values of the outer domain to the inner grid of the inner domain at points along lateral boundaries of the inner domain, the outer domain encompassing the inner domain; interpolating sea surface height η from the outer grid of the outer domain to the inner grid; correcting the interpolated transport values by setting an average of the interpolated transport values to zero for every time interval between each boundary value of the outer domain; determining a total kinetic energy averaged over the inner domain for each of a plurality of coefficient values; selecting an absorption coefficient from the plurality of coefficient values based on the total kinetic energy, wherein the absorption coefficient is a hyperbolic tangent profile that varies spatially across a relaxation zone; setting the relaxation zone adjacent to the lateral boundaries, the relaxation zone having a predetermined width and the absorption coefficient of a predetermined value at an outer edge of the relaxation zone, the relaxation zone enabling outwardly directed fluxes to exit smoothly and without reflection and without generation of artificial perimeter currents, and the relaxation zone enabling fluxes from the outer domain to enter and affect a solution in the inner domain without creating a discontinuity and without being excessively damped; computing the corrected baroclinic normal velocity based on the corrected interpolated transport values, the interpolated sea surface height, and the relaxation zone; and representing a feature of the plurality of features in the numerical model based on the corrected baroclinic normal velocity, wherein the feature is represented in a smaller scale of the inner domain that is not resolved in the outer domain.