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@ARTICLE{Elbern:6304,
      author       = {Elbern, H. and Strunk, A. and Schmidt, H. and Talagrand,
                      O.},
      title        = {{E}mission rate and chemical state estimation by
                      4-dimensional variational inversion},
      journal      = {Atmospheric chemistry and physics},
      volume       = {7},
      issn         = {1680-7316},
      address      = {Katlenburg-Lindau},
      publisher    = {EGU},
      reportid     = {PreJuSER-6304},
      pages        = {3749 - 3769},
      year         = {2007},
      note         = {Record converted from VDB: 12.11.2012},
      abstract     = {This study aims to assess the potential and limits of an
                      advanced inversion method to estimate pollutant precursor
                      sources mainly from observations. Ozone, sulphur dioxide,
                      and partly nitrogen oxides observations are taken to infer
                      source strength estimates. As methodology, the
                      four-dimensional variational data assimilation technique has
                      been generalised and employed to include emission rate
                      optimisation, in addition to chemical state estimates as
                      usual objective of data assimilation. To this end, the
                      optimisation space of the variational assimilation system
                      has been complemented by emission rate correction factors of
                      19 emitted species at each emitting grid point, involving
                      the University of Cologne mesoscale EURAD model. For
                      validation, predictive skills were assessed for an August
                      1997 ozone episode, comparing forecast performances of pure
                      initial value optimisation, pure emission rate optimisation,
                      and joint emission rate/initial value
                      optimisation.Validation procedures rest on both measurements
                      withheld from data assimilation and prediction skill
                      evaluation of forecasts after the inversion procedures.
                      Results show that excellent improvements can be claimed for
                      sulphur dioxide forecasts, after emission rate optimisation.
                      Significant improvements can be claimed for ozone forecasts
                      after initial value and joint emission rate/initial value
                      optimisation of precursor constituents. The additional
                      benefits applying joint emission rate/initial value
                      optimisation are moderate, and very useful in typical cases,
                      where upwind emission rate optimisation is essential. In
                      consequence of the coarse horizontal model grid resolution
                      of 54 km, applied in this study, comparisons indicate that
                      the inversion improvements can rest on assimilating ozone
                      observations only, as the inclusion of NOx observations does
                      not provide additional forecast skill. Emission estimates
                      were found to be largely independent from initial guesses
                      from emission inventories, demonstrating the potential of
                      the 4D-var method to infer emission rate improvements. The
                      study also points to the need for improved horizontal model
                      resolution to more efficient use of NOx observations.},
      keywords     = {J (WoSType)},
      cin          = {ICG-2},
      ddc          = {550},
      cid          = {I:(DE-Juel1)VDB791},
      pnm          = {Atmosphäre und Klima},
      pid          = {G:(DE-Juel1)FUEK406},
      shelfmark    = {Meteorology $\&$ Atmospheric Sciences},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000248733100005},
      url          = {https://juser.fz-juelich.de/record/6304},
}