Challenges of Increased Resolution for the Local Ensemble Tangent Linear Model
Douglas R Allen, Sergey Frolov, Rolf Langland, Craig H Bishop, Karl W Hoppel, David D Kuhl, Max Yaremchuk
Monthly Weather Review | American Meteorological Society | Published : 2020
An ensemble-based linearized forecast model has been developed for data assimilation applications for numerical weather prediction. Previous studies applied this local ensemble tangent linear model (LETLM) to various models, from simple one-dimensional models to a low-resolution (~2.5°) version of the Navy Global Environmental Model (NAVGEM) atmospheric forecast model. This paper applies the LETLM to NAVGEM at higher resolution (~1°), which required overcoming challenges including 1) balancing the computational stencil size with the ensemble size, and 2) propagating fast-moving gravity modes in the upper atmosphere. The first challenge is addressed by introducing a modified local influence v..View full abstract
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This work was funded by the U.S. Office of Naval Research. NAVGEM analyses and forecasts as well as LETLM and TLM forecasts were produced under a grant of computer time from the Department of Defense High Performance Computing Modernization Program. This work also benefitted from the helpful comments and suggestions by two anonymous reviewers.