Skip to main content
Have a personal or library account? Click to login
Four-dimensional variational data assimilation for a limited area model Cover

Four-dimensional variational data assimilation for a limited area model

Open Access
|Dec 2012

Abstract

A 4-dimensional variational data assimilation (4D-Var) scheme for the HIgh Resolution Limited Area Model (HIRLAM) forecasting system is described in this article. The innovative approaches to the multi-incremental formulation, the weak digital filter constraint and the semi-Lagrangian time integration are highlighted with some details. The implicit dynamical structure functions are discussed using single observation experiments, and the sensitivity to various parameters of the 4D-Var formulation is illustrated. To assess the meteorological impact of HIRLAM 4D-Var, data assimilation experiments for five periods of 1 month each were performed, using HIRLAM 3D-Var as a reference. It is shown that the HIRLAM 4D-Var consistently out-performs the HIRLAM 3D-Var, in particular for cases with strong mesoscale storm developments. The computational performance of the HIRLAM 4D-Var is also discussed.

The review process was handled by Subject Editor Abdel Hannachi

Language: English
Page range: 14985 - 14985
Submitted on: May 31, 2011
Accepted on: Dec 7, 2011
Published on: Dec 1, 2012
Published by: Stockholm University Press
In partnership with: Paradigm Publishing Services

© 2012 Nils Gustafsson, Xiang-Yu Huang, Xiaohua Yang, Kristian Mogensen, Magnus Lindskog, Ole Vignes, Tomas Wilhelmsson, Sigurdur Thorsteinsson, published by Stockholm University Press
This work is licensed under the Creative Commons Attribution 4.0 License.