Title: The GEOS ozone data assimilation system: Specification of error statistics
Abstract: Quarterly Journal of the Royal Meteorological SocietyVolume 127, Issue 573 p. 1069-1094 Article The GEOS ozone data assimilation system: Specification of error statistics Ivanka Štajner, Corresponding Author Ivanka Štajner [email protected] NASA Goddard Space Flight Center, USA General Sciences Corporation, USAData Assimilation Office, Code 910.3, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USASearch for more papers by this authorLars Peter Riishøjgaard, Lars Peter Riishøjgaard NASA Goddard Space Flight Center, USA University of Maryland Baltimore County, USASearch for more papers by this authorRichard B. Rood, Richard B. Rood NASA Goddard Space Flight Center, USASearch for more papers by this author Ivanka Štajner, Corresponding Author Ivanka Štajner [email protected] NASA Goddard Space Flight Center, USA General Sciences Corporation, USAData Assimilation Office, Code 910.3, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USASearch for more papers by this authorLars Peter Riishøjgaard, Lars Peter Riishøjgaard NASA Goddard Space Flight Center, USA University of Maryland Baltimore County, USASearch for more papers by this authorRichard B. Rood, Richard B. Rood NASA Goddard Space Flight Center, USASearch for more papers by this author First published: April 2001 Part A https://doi.org/10.1002/qj.49712757320Citations: 60AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract A global three-dimensional ozone data assimilation system has been developed at the Data Assimilation Office of the NASA Goddard Space Flight Center. The Total Ozone Mapping Spectrometer (TOMS) total ozone data and the Solar Backscatter Ultraviolet/2 (SBUV/2) partial ozone profile observations are assimilated. The assimilation, into an off-line ozone transport model, is done using the global Physical-space Statistical Analysis Scheme. This system became operational in December 1999. A detailed description of the statistical analysis scheme and, in particular, of the forecast- and observation-error covariance models is given. A new global anisotropic horizontal forecast-error correlation model accounts for a varying distribution of observations with latitude. Correlations are largest in the zonal direction in the tropics where data are sparse. Forecast-error variance is assumed to be proportional to the ozone field. The forecast-error covariance parameters were determined by maximum-likelihood estimation. The error covariance models are validated using χ2 statistics. The analysed ozone fields in the winter 1992 are validated against independent observations from ozone sondes and the Halogen Occultation Experiment (HALOE). The difference between the mean HALOE observations and the analysis fields is less than 10% at pressure levels between 70 and 0.2 hPa. The global root-mean-square difference between TOMS observed and forecast values is less than 4%. The global root-mean-square difference between SBUV observed and analysed ozone between 50 and 3 hPa is less than 15%. Citing Literature Volume127, Issue573April 2001 Part APages 1069-1094 RelatedInformation