• Login
     
    View Item 
    •   ORFEO Home
    • Royal Belgian Institute for Space Aeronomy
    • BIRA-IASB publications
    • View Item
    •   ORFEO Home
    • Royal Belgian Institute for Space Aeronomy
    • BIRA-IASB publications
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    The ASSET intercomparison of stratosphere and lower mesosphere humidity analyses

    Thumbnail
    View/Open
    Thornton(2009).pdf (8.607Mb)
    Authors
    Thornton, H.E.
    Jackson, D.R.
    Bekki, S.
    Bormann, N.
    Errera, Q.
    Geer, A.J.
    Lahoz, W.A.
    Rharmili, S.
    Show allShow less
    Discipline
    Physical sciences
    Subject
    atmospheric modeling
    complexity
    covariance analysis
    data assimilation
    Envisat-1
    matrix
    mesosphere
    numerical model
    relative humidity
    satellite data
    satellite imagery
    stratosphere
    water vapor
    Audience
    Scientific
    Date
    2009
    Metadata
    Show full item record
    Description
    This paper presents results from the first detailed intercomparison of stratosphere-lower mesosphere water vapour analyses; it builds on earlier results from the EU funded framework V "Assimilation of ENVISAT Data" (ASSET) project. Stratospheric water vapour plays an important role in many key atmospheric processes and therefore an improved understanding of its daily variability is desirable. With the availability of high resolution, good quality Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) water vapour profiles, the ability of four different atmospheric models to assimilate these data is tested. MIPAS data have been assimilated over September 2003 into the models of the European Centre for Medium Range Weather Forecasts (ECMWF), the Belgian Institute for Space and Aeronomy (BIRA-IASB), the French Service d'Áeronomie (SA-IPSL) and the UK Met Office. The resultant middle atmosphere humidity analyses are compared against independent satellite data from the Halogen Occultation Experiment (HALOE), the Polar Ozone and Aerosol Measurement (POAM III) and the Stratospheric Aerosol and Gas Experiment (SAGE II). The MIPAS water vapour profiles are generally well assimilated in the ECMWF, BIRA-IASB and SA systems, producing stratosphere-mesosphere water vapour fields where the main features compare favourably with the independent observations. However, the models are less capable of assimilating the MIPAS data where water vapour values are locally extreme or in regions of strong humidity gradients, such as the southern hemisphere lower stratosphere polar vortex. Differences in the analyses can be attributed to the choice of humidity control variable, how the background error covariance matrix is generated, the model resolution and its complexity, the degree of quality control of the observations and the use of observations near the model boundaries. Due to the poor performance of the Met Office analyses the results are not included in the intercomparison, but are discussed separately. The Met Office results highlight the pitfalls in humidity assimilation, and provide lessons that should be learnt by developers of stratospheric humidity assimilation systems. In particular, they underline the importance of the background error covariances in generating a realistic troposphere to mesosphere water vapour analysis.
    Citation
    Thornton, H.E.; Jackson, D.R.; Bekki, S.; Bormann, N.; Errera, Q.; Geer, A.J.; Lahoz, W.A.; Rharmili, S. (2009). The ASSET intercomparison of stratosphere and lower mesosphere humidity analyses. , Atmospheric Chemistry and Physics, Vol. 9, Issue 3, 995-1016,
    Identifiers
    uri: https://orfeo.belnet.be/handle/internal/3259
    scopus: 2-s2.0-77950292504
    Type
    Article
    Peer-Review
    Yes
    Language
    eng
    Links
    NewsHelpdeskBELSPO OA Policy

    Browse

    All of ORFEOCommunities & CollectionsBy Issue DateAuthorsTitlesDisciplinesThis CollectionBy Issue DateAuthorsTitlesDisciplines
     

    DSpace software copyright © 2002-2016  DuraSpace
    Send Feedback | Cookie Information
    Theme by 
    Atmire NV