Assimilation of drifter observations for the reconstruction of the Eulerian circulation field

Anne Molcard, Leonid I. Piterbarg, Annalisa Griffa, Tamay M Ozgokmen, Arthur J Mariano

Research output: Contribution to journalArticle

67 Citations (Scopus)

Abstract

In light of the increasing number of drifting buoys in the ocean and recent advances in the realism of ocean general circulation models toward oceanic forecasting, the problem of assimilation of Lagrangian observations data in Eulerian models is investigated. A new and general rigorous approach is developed based on optimal interpolation (OI) methods, which takes into account directly the Lagrangian nature of the observations. An idealized version of this general formulation is tested in the framework of identical twin experiments using a reduced gravity, quasi-geostrophic model. An extensive study is conducted to quantify the effectiveness of Lagrangian data assimilation as a function of the number of drifters, the frequency of assimilation, and the uncertainties associated with the forcing functions driving the ocean model. The performance of the Lagrangian assimilation technique is also compared to that of conventional methods of assimilating drifters as moving current meters, and assimilation of Eulerian data, such as fixed-point velocities. Overall, the results are very favorable for the assimilation of Lagrangian observations to improve the Eulerian velocity field in ocean models. The results of our assimilation twin experiments imply an optimal sampling frequency for oceanic Lagrangian instruments in the range of 20-50% of the Lagrangian integral timescale of the flow field.

Original languageEnglish (US)
Pages (from-to)1
Number of pages1
JournalJournal of Geophysical Research C: Oceans
Volume108
Issue number3
StatePublished - Mar 15 2003

Fingerprint

drifter
assimilation
ocean
ocean models
Buoys
oceans
oceanic general circulation model
Eulerian analysis
buoys
Flow fields
Interpolation
Gravitation
data assimilation
flow field
Experiments
interpolation
microgravity
Sampling
forecasting
experiment

Keywords

  • Drifters
  • Eulerian velocity
  • Lagrangian assimilation
  • Lagrangian velocity
  • Numerical model

ASJC Scopus subject areas

  • Earth and Planetary Sciences (miscellaneous)
  • Atmospheric Science
  • Geochemistry and Petrology
  • Geophysics
  • Oceanography
  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Assimilation of drifter observations for the reconstruction of the Eulerian circulation field. / Molcard, Anne; Piterbarg, Leonid I.; Griffa, Annalisa; Ozgokmen, Tamay M; Mariano, Arthur J.

In: Journal of Geophysical Research C: Oceans, Vol. 108, No. 3, 15.03.2003, p. 1.

Research output: Contribution to journalArticle

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