A comparative study of 4D-VAR and a 4D Ensemble Kalman Filter: Perfect model simulations with Lorenz-96

Elana J. Fertig, John Harlim, Brian R. Hunt

Research output: Contribution to journalArticle

74 Scopus citations

Abstract

We formulate a four-dimensional Ensemble Kalman Filter (4D-LETKF) that minimizes a cost function similar to that in a 4D-VAR method. Using perfect model experiments with the Lorenz-96 model, we compare assimilation of simulated asynchronous observations with 4D-VAR and 4D-LETKF. We find that both schemes have comparable error when 4D-LETKF is performed sufficiently frequently and when 4D-VAR is performed over a sufficiently long analysis time window. We explore how the error depends on the time between analyses for 4D-LETKF and the analysis time window for 4D-VAR.

Original languageEnglish (US)
Pages (from-to)96-100
Number of pages5
JournalTellus, Series A: Dynamic Meteorology and Oceanography
Volume59
Issue number1
DOIs
StatePublished - Jan 1 2007

All Science Journal Classification (ASJC) codes

  • Oceanography
  • Atmospheric Science

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