Tests of an ensemble Kalman filter for mesoscale and regional-scale data assimilation. Part III

Comparison with 3DVAR in a real-data case study

Zhiyong Meng, Fuqing Zhang

Research output: Contribution to journalArticle

114 Citations (Scopus)

Abstract

The feasibility of using an ensemble Kalman filter (EnKF) for mesoscale and regional-scale data assimilation has been demonstrated in the authors' recent studies via observing system simulation experiments (OSSEs) both under a perfect-model assumption and in the presence of significant model error. The current study extends the EnKF to assimilate real-data observations for a warm-season mesoscale convective vortex (MCV) event on 10-12 June 2003. Direct comparison between the EnKF and a three-dimensional variational data assimilation (3DVAR) system, both implemented in the Weather Research and Forecasting model (WRF), is carried out. It is found that the EnKF consistently performs better than the 3DVAR method by assimilating either individual or multiple data sources (i.e., sounding, surface, and wind profiler) for this MCV event. Background error covariance plays an important role in the performance of both the EnKF and the 3DVAR system. Proper covariance inflation and the use of different combinations of physical parameterization schemes in different ensemble members (the so-called multfseheme ensemble) can significantly improve the EnKF performance. The 3DVAR system can benefit substantially from using short-term ensembles to improve the prior estimate (with the ensemble mean). Noticeable improvement is also achieved by including some flow dependence in the background error covariance of 3DVAR.

Original languageEnglish (US)
Pages (from-to)522-540
Number of pages19
JournalMonthly Weather Review
Volume136
Issue number2
DOIs
StatePublished - Feb 1 2008

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Kalman filter
data assimilation
vortex
profiler
inflation
test
comparison
parameterization
weather
simulation
experiment

All Science Journal Classification (ASJC) codes

  • Atmospheric Science

Cite this

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Tests of an ensemble Kalman filter for mesoscale and regional-scale data assimilation. Part III : Comparison with 3DVAR in a real-data case study. / Meng, Zhiyong; Zhang, Fuqing.

In: Monthly Weather Review, Vol. 136, No. 2, 01.02.2008, p. 522-540.

Research output: Contribution to journalArticle

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