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ZLF (Zero Lateral Flux): a simple mass conservation method for semi‐Lagrangian‐based limited‐area models
Author(s) -
Zerroukat M.,
Shipway B. J.
Publication year - 2017
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.3108
Subject(s) - simple (philosophy) , conservation of mass , scheme (mathematics) , advection , lagrangian , mathematical optimization , mathematics , conservation law , computer science , flux (metallurgy) , algorithm , mathematical analysis , physics , mechanics , philosophy , epistemology , thermodynamics , materials science , metallurgy
In this paper we outline a simple method to achieve mass conservation with semi‐Lagrangian‐based limited‐area models (SL‐LAMs). Imposing mass conservation with LAMs requires knowledge of advective fluxes across their lateral boundaries. Estimation of these fluxes within a semi‐Lagrangian scheme can be problematic. Methods have been devised to achieve this, however these require extra interpolations which increase the computational cost of the model. By exploiting the way these models are designed and under some mild assumptions, a simple scheme is proposed which avoids computing the lateral fluxes altogether. The scheme achieves the same objectives as the earlier methods, but with minimal extra computational cost. This scheme is validated in a simple one‐dimensional problem and then implemented in a full atmospheric model to show its effectiveness.