Articles | Volume 15, issue 9
Atmos. Chem. Phys., 15, 5275–5303, 2015

Special issue: Monitoring atmospheric composition and climate, research in...

Special issue: Coupled chemistry–meteorology modelling: status and...

Atmos. Chem. Phys., 15, 5275–5303, 2015

Research article 13 May 2015

Research article | 13 May 2015

Data assimilation of satellite-retrieved ozone, carbon monoxide and nitrogen dioxide with ECMWF's Composition-IFS

A. Inness1, A.-M. Blechschmidt2, I. Bouarar3, S. Chabrillat4, M. Crepulja1, R. J. Engelen1, H. Eskes5, J. Flemming1, A. Gaudel6,7, F. Hendrick4, V. Huijnen5, L. Jones1, J. Kapsomenakis8, E. Katragkou9, A. Keppens4, B. Langerock4, M. de Mazière4, D. Melas10, M. Parrington1, V. H. Peuch1, M. Razinger1, A. Richter2, M. G. Schultz11, M. Suttie1, V. Thouret6,7, M. Vrekoussis8,12, A. Wagner13, and C. Zerefos8 A. Inness et al.
  • 1ECMWF, Reading, UK
  • 2Institute of Environmental Physics, University of Bremen, Germany
  • 3Max Planck Institute for Meteorology, Hamburg, Germany
  • 4Belgian Institute for Space Aeronomy (BIRA-IASB), Brussels, Belgium
  • 5Royal Netherlands Meteorological Institute, De Bilt, the Netherlands
  • 6Université de Toulouse, UPS, LA (Laboratoire d'Aérologie), Toulouse, France
  • 7CNRS, LA (Laboratoire d'Aérologie), UMR 5560, 31400 Toulouse, France
  • 8Research Center for Atmospheric Physics and Climatology, Academy of Athens, Athens, Greece
  • 9Department of Meteorology and Climatology, School of Geology, Aristotle University of Thessaloniki, Thessaloniki, Greece
  • 10Laboratory of Atmospheric Physics, School of Physics, Aristotle University of Thessaloniki, Thessaloniki, Greece
  • 11Forschungszentrum Jülich, Jülich, Germany
  • 12Energy, Environment and Water Research Center (EEWRC), The Cyprus Institute, Nicosia, Cyprus
  • 13Deutscher Wetterdienst, Meteorologisches Observatorium Hohenpeissenberg, Germany

Abstract. Daily global analyses and 5-day forecasts are generated in the context of the European Monitoring Atmospheric Composition and Climate (MACC) project using an extended version of the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF). The IFS now includes modules for chemistry, deposition and emission of reactive gases, aerosols, and greenhouse gases, and the 4-dimensional variational data assimilation scheme makes use of multiple satellite observations of atmospheric composition in addition to meteorological observations. This paper describes the data assimilation setup of the new Composition-IFS (C-IFS) with respect to reactive gases and validates analysis fields of ozone (O3), carbon monoxide (CO), and nitrogen dioxide (NO2) for the year 2008 against independent observations and a control run without data assimilation. The largest improvement in CO by assimilation of Measurements of Pollution in the Troposphere (MOPITT) CO columns is seen in the lower troposphere of the Northern Hemisphere (NH) extratropics during winter, and during the South African biomass-burning season. The assimilation of several O3 total column and stratospheric profile retrievals greatly improves the total column, stratospheric and upper tropospheric O3 analysis fields relative to the control run. The impact on lower tropospheric ozone, which comes from the residual of the total column and stratospheric profile O3 data, is smaller, but nevertheless there is some improvement particularly in the NH during winter and spring. The impact of the assimilation of tropospheric NO2 columns from the Ozone Monitoring Instrument (OMI) is small because of the short lifetime of NO2, suggesting that NO2 observations would be better used to adjust emissions instead of initial conditions. The results further indicate that the quality of the tropospheric analyses and of the stratospheric ozone analysis obtained with the C-IFS system has improved compared to the previous "coupled" model system of MACC.

Short summary
The paper presents results from data assimilation studies with the new Composition-IFS model developed in the MACC project. This system was used in MACC to produce daily analyses and 5-day forecasts of atmospheric composition and is now run daily in the EU’s Copernicus Atmosphere Monitoring Service. The paper looks at the quality of the CO, O3 and NO2 analysis fields obtained with this system, comparing them against observations, a control run and an older version of the model.
Final-revised paper