The Assimilation of Envisat data (ASSET) project W. A. Lahoz1, A. J. Geer1,*, S. Bekki2, N. Bormann3, S. Ceccherini4, H. Elbern5, Q. Errera6, H. J. Eskes7, D. Fonteyn6, D. R. Jackson8, B. Khattatov9, M. Marchand2, S. Massart10, V.-H. Peuch11, S. Rharmili2, M. Ridolfi12, A. Segers7, O. Talagrand13, H. E. Thornton8, A. F. Vik14, and T. von Clarmann15 1Data Assimilation Research Centre, University of Reading, Reading, UK 2Service Aeronomie, Universite Pierre et Marie Curie, Paris, France 3ECMWF, Reading, UK 4CNR-IFAC, Florence, Italy 5RIU, University of Köln, Köln, Germany 6BIRA-IASB, Brussels, Belgium 7KNMI, De Bilt, The Netherlands 8Met Office, Exeter, UK 9Fusion Numerics, Boulder, CO, USA 10CERFACS, Toulouse, France 11Météo-France, Toulouse, France 12University of Bologna, Bologna, Italy 13LMD, Paris, France 14NILU, Kjeller, Norway 15Forschungszentrum Karlsruhe, IMK, Germany *now at: ECMWF, Reading, UK
Abstract. This paper discusses the highlights of the EU-funded "Assimilation of
Envisat data" (ASSET) project, which has involved assimilation of Envisat
atmospheric constituent and temperature data into systems based on Numerical
Weather Prediction (NWP) models and chemical transport models (CTMs).
Envisat was launched in 2002 and is one of the largest Earth Observation
(EO) satellites ever built. It carries several sophisticated EO instruments
providing insights into chemistry and dynamics of the atmosphere. In this paper
we focus on the assimilation of temperature and constituents from Envisat.
The overarching theme of the ASSET project has been to bring together experts
from all aspects of the data assimilation problem. This has allowed ASSET to
address several themes comprehensively: enhancement of NWP analyses by
assimilation of research satellite data; studies of the distribution of
stratospheric chemical species by assimilation of research satellite data
into CTM systems; objective assessment of the quality of ozone analyses;
studies of the spatial and temporal evolution of tropospheric pollutants;
enhanced retrievals of Envisat data; and data archival and dissemination.
Among the results from the ASSET project, many of which are firsts in their
field, we can mention: a positive impact on NWP analyses from assimilation
of height-resolved stratospheric humidity and temperature data, and
assimilation of limb radiances; the extraction of temperature information
from the assimilation of chemical species into CTMs; a first intercomparison
between ozone assimilation systems; the extraction of information on
tropospheric pollution from assimilation of Envisat data; and the large
potential of the Envisat MIPAS dataset. This paper discusses these, often
novel, developments and results. Finally, achievements of, and
recommendations from, the ASSET project are presented.
Citation: Lahoz, W. A., Geer, A. J., Bekki, S., Bormann, N., Ceccherini, S., Elbern, H., Errera, Q., Eskes, H. J., Fonteyn, D., Jackson, D. R., Khattatov, B., Marchand, M., Massart, S., Peuch, V.-H., Rharmili, S., Ridolfi, M., Segers, A., Talagrand, O., Thornton, H. E., Vik, A. F., and von Clarmann, T.: The Assimilation of Envisat data (ASSET) project, Atmos. Chem. Phys., 7, 1773-1796, doi:10.5194/acp-7-1773-2007, 2007.