Publication Date:
2019
Description:
Abstract
Most global models employ a vertical coordinate based on the moist hydrostatic pressure, and therefore do not conserve dry air mass. Such issue should be seriously taken into account, especially in developing global high‐resolution atmospheric model to explicitly address non‐hydrostatic motions. In this paper, we present a modified non‐hydrostatic moist global spectral dynamical core using a dry‐mass vertical coordinate, which conserves the mass of dry air naturally. In addition to the vertical coordinate, the modified dynamical core differs from the original Aladin‐NH like dynamical kernel in the employed state variables. Specifically, a new temperature variable is introduced to formulate the governing equations and the mass continuity equation is expressed in terms of the dry air density. To assess its performance, an idealized splitting supercell test is conducted. Simulation results from both the modified and original dynamical cores are presented and compared. The results indicate that only the modified dynamic core is able to simulate the splitting supercell with good accuracy comparable to reference solutions from the Model for Prediction Across Scales (MPAS).
Print ISSN:
0035-9009
Electronic ISSN:
1477-870X
Topics:
Geography
,
Physics
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