Atmospheric Chemistry and Physics
www.atmos-chem-phys.net
1680-7316
1680-7324
6
12
2006
10.5194/acp-6-5445-2006
http://www.atmos-chem-phys.net/6/5445/2006/
http://www.atmos-chem-phys.net/6/5445/2006/acp-6-5445-2006.html
http://www.atmos-chem-phys.net/6/5445/2006/acp-6-5445-2006.pdf
5445
5474
2006-12-05
The ASSET intercomparison of ozone analyses: method and first results
A. J. Geer
alan.geer@ecmwf.int
W. A. Lahoz
S. Bekki
N. Bormann
Q. Errera
H. J. Eskes
D. Fonteyn
D. R. Jackson
M. N. Juckes
S. Massart
V.-H. Peuch
S. Rharmili
A. Segers
Data Assimilation Research Centre, University of Reading, Reading, UK
CNRS Service Aeronomie, Université Pierre et Marie Curie, Paris, France
European Centre for Medium-Range Weather Forecasts, Reading, UK
Institut d'Aéronomie Spatiale de Belgique, Brussels, Belgium
Royal Netherlands Meteorological Institute, De Bilt, The Netherlands
Met Office, Exeter, UK
British Atmospheric Data Centre, Rutherford Appleton Laboratory, Chilton, nr Didcot, UK
CERFACS, Toulouse, France
CNRM-GAME, Météo-France and CNRS URA 1357, Toulouse, France
Now at European Centre for Medium-Range Weather Forecasts, Reading, UK
This paper aims to summarise the current
performance of ozone data assimilation (DA) systems, to show where they can be
improved, and to quantify their errors. It examines 11 sets of ozone
analyses from 7 different DA systems. Two are numerical weather
prediction (NWP) systems based on general circulation models (GCMs); the
other five use chemistry transport models (CTMs). The systems examined
contain either linearised or detailed ozone chemistry, or no chemistry at
all. In most analyses, MIPAS (Michelson
Interferometer for Passive Atmospheric Sounding) ozone data are assimilated;
two assimilate SCIAMACHY (Scanning Imaging Absorption Spectrometer
for Atmospheric Chartography) observations instead.
Analyses are compared to independent ozone observations covering the
troposphere, stratosphere and lower mesosphere during the period July to
November 2003.
<br><br>
Biases and standard deviations are largest, and show the largest divergence
between systems, in the troposphere, in the
upper-troposphere/lower-stratosphere, in the upper-stratosphere and
mesosphere, and the Antarctic ozone hole region. However, in any particular
area, apart from the troposphere, at least one system can be found that
agrees well with independent data. In general, none of the differences can be
linked to the assimilation technique (Kalman filter, three or four
dimensional variational methods, direct inversion) or the system (CTM or NWP
system). Where results diverge, a main explanation is the way ozone is
modelled. It is important to correctly model transport at the tropical
tropopause, to avoid positive biases and excessive structure in the ozone
field. In the southern hemisphere ozone hole, only the analyses which
correctly model heterogeneous ozone depletion are able to reproduce the
near-complete ozone destruction over the pole. In the upper-stratosphere and
mesosphere (above 5 hPa), some ozone photochemistry schemes caused large but
easily remedied biases. The diurnal cycle of ozone in the mesosphere is not
captured, except by the one system that includes a detailed treatment of
mesospheric chemistry. These results indicate that when good observations are
available for assimilation, the first priority for improving ozone DA systems
is to improve the models.
<br><br>
The analyses benefit strongly from the good quality of the MIPAS ozone
observations. Using the analyses as a transfer standard, it is seen that
MIPAS is ~5% higher than HALOE (Halogen Occultation Experiment) in the
mid and upper stratosphere and mesosphere (above 30 hPa), and of order 10%
higher than ozonesonde and HALOE in the lower stratosphere (100 hPa to
30 hPa). Analyses based on SCIAMACHY total column are almost as good as the
MIPAS analyses; analyses based on SCIAMACHY limb profiles are worse in some
areas, due to problems in the SCIAMACHY retrievals.
Andersson, E. and Järvinen, H.: Variational quality control, Q. J. R. Meteorol. Soc., 125, 697–722, 1999.
Austin, J., Shindell, D., Beagley, S R., Brühl, C., Dameris, M., Manzini, E., Nagashima, T., Newman, P., Pawson, S., Pitari, G., Rozanov, E., Schnadt, C., and Shepherd, T G.: Uncertainties and assessments of chemistry-climate models of the stratosphere, Atmos. Chem. Phys., 3, 1–27, 2003
Bhartia, P K., McPeters, R D., Mateer, C L., Flynn, L E., and Wellemeyer, C.: Algorithm for the estimation of vertical ozone profiles from the backscattered ultraviolet technique, J. Geophys. Res., 101, 18 793–18 806, 1996.
Bhatt, P P., Remsberg, E E., Gordley, L L., McInerney, J M., Brackett, V G., and Russell, J M.: An evaluation of the quality of Halogen Occultation Experiment ozone profiles in the lower stratosphere, J. Geophys. Res., 104, 9261–9275, 1999.
Bregman, A., Krol, M C., Teyssedre, H., Norton, W A., Iwi, A., Chipperfield, M., Pitari, G., Sundet, J K., and Lelieveld, J.: Chemistry-transport model comparison with ozone observations in the midlatitude lowermost stratosphere, J. Geophys. Res., 106, 17 479–17 496, 2001.
Bregman, B., Meijer, E., and Scheele, R.: Key aspects of stratospheric tracer modeling, Atmos. Chem. Phys. Discuss., 6, 4375–4414, 2006
Cariolle, D. and Déqué, M.: Southern-Hemisphere Medium-Scale Waves and Total Ozone Disturbances in a Spectral General Circulation Model, J. Geophys. Res., 91, 10 825–10 846, 1986.
Cariolle, D. and Morcrette, J.-J.: A linearized approach to the radiative budget of the stratosphere: influence of the ozone distribution, Geophys. Res. Lett., 33, L05806, doi:10.1029/2005GL025597, 2006.
Carslaw, K S., Luo, B., and Peter, T.: An analytic expression for the composition of aqueous \chemHNO_3-H_2SO_4 stratospheric aerosols including gas phase removal of \chemHNO_3, Geophys. Res. Lett., 22, 1877–1880, 1995.
Cathala, M.-L., Pailleux, J., and Peuch, V.-H.: Improving global simulations over the upper troposphere-lower stratosphere with sequential assimilation of MOZAIC data, Tellus, 55B, 1–10, 2003.
Chipperfield, M P., Khattatov, B V., and Lary, D J.: Sequential assimilation of stratospheric chemical observations in a three-dimensional model, J. Geophys. Res., 107, 4585, doi:10.1029/2002JD002110, 2002.
Courtier, P., Freydier, C., Geleyn, J.-F., Rabier, F., and Rochas, M.: The ARPEGE project at Météo-France, ECMWF seminar proceedings, Reading, 9–13 Sept. 1991, vol. II, pp. 193–231, 1991.
Davies, T., Cullen, M J P., Malcolm, A J., Mawson, M H., Staniforth, A., White, A A., and Wood, N.: A new dynamical core for the Met Office's global and regional modelling of the atmosphere, Q. J. R. Meteorol. Soc., 131, 1759–1782, 2005.
Daerden, F., Larsen, N., Chabrillat, S., Errera, Q., Bonjean, S., Fonteyn, D., Hoppel, K., and Fromm, M.: A 3D-CTM with detailed online PSC-microphysics: analysis of the Antarctic winter 2003 by comparison with satellite observations, Atmos. Chem. Phys. Discuss., 6, 8511–8552, 2006.
Dethof, A.: Assimilation of ozone retrievals from the MIPAS instrument on board ENVISAT, ECMWF Technical Memoranda, 428, http://www.ecmwf.int/publications/, 2003a.
Dethof, A.: Monitoring of retrievals from the MIPAS and SCIAMACHY instruments on board ENVISAT, Contract Report to the European Space Agency, European Centre for Medium-Range Weather Forecasts, available from http://www.ecmwf.int, 2003b.
Dethof, A.: Monitoring and assimilation of MIPAS, SCIAMACHY and GOMOS retrievals at ECMWF, Contract Report to the European Space Agency, European Centre for Medium-Range Weather Forecasts, available from http://www.ecmwf.int, 2004.
Dethof, A. and Hólm, E V.: Ozone assimilation in the ERA-40 reanalysis project, Q. J. R. Meteorol. Soc., 130, 2851–2872, 2004.
Dufour, A., Amodei, M., Ancellet, G., and Peuch, V.-H.: Observed and modelled `chemical weather' during ESCOMPTE, Atmos. Res., 74, 161–189, 2004.
El Amraoui, L., Ricaud, P., Urban, J., Theodore, B., Hauchecorne, A., Lautie, N., De La Noe, J., Guirlet, M., Le Flochmoen, E., Murtagh, D., Dupuy, E., Frisk, U., and d'Andon, O F.: Assimilation of Odin/SMR \chemO_3 and \chemN_2O measurements in a three-dimensional chemistry transport model, J. Geophys. Res., 109, D22304, doi:10.1029/2004JD004796, 2004.
Elbern, H. and Schmidt, H.: Ozone episode analysis by four-dimensional variational chemistry data assimilation, J. Geophys. Res., 106, 3569–3590, 2001.
Eskes, H J., Van Velthoven, P F J., Valks, P J M., and Kelder, H M.: Assimilation of GOME total-ozone satellite observations in a three-dimensional tracer-transport model, Q. J. R. Meteorol. Soc., 129, 1663–1681, 2003.
Eskes, H J., Segers, A J., and Van Velthoven, P F J.: Ozone Forecasts of the Stratospheric Polar Vortex Splitting Event in September 2002, J. Atmos. Sci., 62, 812–821, 2005a.
Eskes, H J., van der A, R J., Brinksma E J., Veefkind, J P., de Haan, J F., and Valks, P J M.: Retrieval and validation of ozone columns derived from measurements of SCIAMACHY on Envisat, Atmos. Chem. Phys. Discuss., 5, 4429–4475, 2005b.
Errera, Q. and Fonteyn, D.: Four-dimensional variational chemical assimilation of CRISTA stratospheric measurements, J. Geophys. Res., 106, 12 253–12 265, 2001.
European Space Agency: MIPAS Product Handbook, issue 1.2, available from http://envisat.esa.int/dataproducts, 2004.
Fierli, F., Hauchecorne, A., Bekki, S., Theodore, B., and Fanton D'Andon, O.: Data assimilation of stratospheric ozone using a high-resolution transport model, Geophys. Res. Lett., 29, doi:10.1029/2001GL014272, 2002.
Fischer, H. and Oelhaf, H.: Remote sensing of vertical profiles of atmospheric trace constituents with MIPAS limb-emission spectrometers, Appl. Opt., 35, 2787–2796, 1996.
Fischer, H. and Oelhaf, H.: Summary of the MIPAS validation results, Proceedings of the Second Workshop on the Atmospheric Chemistry Validation of Envisat (ACVE-2), 3–7 May 2004, ESA-ESRIN, Frascati, Italy, ESA SP-562, http://envisat.esa.int/workshops/acve2/contents.html, 2004.
Fisher, M.: Background error covariance modelling, Proceedings of the ECMWF Seminar on recent developments in data assimilation from atmosphere and ocean, 8–12 September 2003, ECMWF, Reading, UK, pp. 45–64, 2003.
Fisher, M. and Andersson, E.: Developments in 4D-Var and Kalman Filtering, ECMWF Technical Memoranda, 347, 2001.
Fisher, M. and Lary, D J.: Lagrangian 4-dimensional variational data assimilation of chemical-species, Q. J. R. Meteorol. Soc., 121, 1681–1704, 1995.
Fortuin, J P F. and Kelder, H.: An ozone climatology based on ozonesonde and satellite measurements, J. Geophys. Res., 103, 31 709–31 734, 1998.
Fortuin, J P F. and Langematz, U.: An update on the global ozone climatology and on concurrent ozone and temperature trends, SPIE Proceedings Series, Atmos. Sens. Modeling, Vol. 2311, pp. 207–216, 1995.
Gates, W L.: AMIP: The Atmospheric Model Intercomparison Project, Bull. Am. Met. Soc., 73, 1962–1970, 1992.
Gauthier, P., Chouinard, C., and Brasnett, B.: Quality control: Methodology and applications, Data Assimilation for the Earth System, edited by: Swinbank, R., Shutyaev, V., and Lahoz, W. A.: Kluwer Academic Publications, Dordrecht, The Netherlands, pp. 177–187, 2003.
Geer, A J., Lahoz, W A., Jackson, D R., Cariolle, D., and McCormack, J P.: Evaluation of linear ozone photochemistry parametrizations in a stratosphere-troposphere data assimilation system, Atmos. Chem. Phys. Discuss., 6, 7427–7469, 2006a.
Geer, A J., Peubey, C., Bannister, R N., Brugge, R., Jackson, D R., Lahoz, W A., Migliorini, S., O'Neill, A., and Swinbank, R.: Assimilation of stratospheric ozone from MIPAS into a global general circulation model: the September 2002 vortex split, Q. J. R. Meteorol. Soc., 132, 231–257, 2006b.
Hervig, M. and McHugh, M.: Cirrus detection using HALOE measurements, Geophys. Res. Lett., 26, 719–722, 1999.
Hudson, R D., Frolov, A D., Andrade, M F., and Follette, M B.: The total ozone field separated into meteorological regimes. Part I: defining the regimes, J. Atmos. Sci., 60, 1669–1677, 2003.
Jackson, D R.: Improvements in data assimilation at the Met Office, Met Office Forecasting Research Technical Report, 454, 2004.
Jackson, D R. and Saunders, R.: Ozone Data Assimilation: Preliminary System, Met Office Forecasting Research Technical Report, 394, 2002.
Josse, B., Simon, P., and Peuch V.-H.: Radon global simulations with the multiscale chemistry and transport model MOCAGE, Tellus, 56B, 339–356, 2004.
Juckes, M N.: Evaluation of MIPAS ozone fields assimilated using a new algorithm constrained by isentropic tracer advection, Atmos. Chem. Phys., 6, 1549–1565, 2006a.
Juckes, M N.: An annual cycle of long lived stratospheric gases from MIPAS, Atmos. Chem. Phys. Discuss., 6, 9389–9429, 2006b.
Kalnay, E.: Atmospheric modeling, data assimilation and predictability, Cambridge University Press, UK, 2003.
Khattatov, B V., Lamarque, J F., Lyjak, L V., Ménard, R., Levelt, P., Tie, X X., Brasseur, G P., and Gille, J C.:, Assimilation of satellite observations of long-lived chemical species in global chemistry transport models, J. Geophys. Res., 105, 29 135–29 144, 2000.
Komhyr, W D., Barnes, R A., Brothers, G B., Lathrop, J A., and Opperman, D P.: Electrochemical Concentration Cell Ozonesonde Performance Evaluation During STOIC 1989, J. Geophys. Res., 100, 9231–9244, 1995.
Lagarde, T., Piacentini, A., and Thual, O.: A New Representation of Data Assimilation Methods: the PALM Flow Charting Approach, Q. J. R. Meteorol. Soc., 127, 189–207, 2001.
Lahoz, W A., Geer, A J., and O'Neill, A.: Dynamical evolution of the 2003 southern hemisphere stratospheric winter using Envisat trace-gas observations, Q. J. R. Meteorol. Soc., 132, 1985–2008, 2006.
Larsen, N.: Polar Stratospheric Clouds. Microphysical and optical models, Scientific report 00-06, Danish Meteorological Institute, available from http://www.dmi.dk/, 2000.
Lefèvre, F., Brasseur, G P., Folkins, I., Smith, A K., and Simon, P.: Chemistry of the 1991–1992 stratospheric winter: three-dimensional model simulations, J. Geophys. Res., 99(D4), 8183–8195, 1994.
Lefèvre, F., Figarol, F., Carslaw, K S., and Peter, T.: The 1997 Arctic ozone depletion quantified from three-dimensional model simulations, Geophys. Res. Lett., 25, 2425–2428, 1998.
Li, D. and Shine K P.: A 4-dimensional ozone climatology for UGAMP models, UGAMP Int. Rep., 35, April 1995.
Logan, J A.: An analysis of ozonesonde data for the troposphere: Recommendations for testing 3-D models and development of a gridded climatology for tropospheric ozone, J. Geophys. Res., 104, 16 115–16 149, 1999.
Lorenc, A C., Ballard, S P., Bell, R S., Ingleby, N B., Andrews, P L F., Barker, D M., Bray, J R., Clayton, A M., Dalby, T D., Li, D., Payne, T J., and Saunders, F W.: The Met. Office global three-dimensional variational data assimilation scheme, Q. J. R. Meteorol. Soc., 126, 2991–3012, 2000.
McCormack, J P., Eckermann, S D., Coy, L., Allen, D R., Kim, Y.-J., Hogan, T., Lawrence, B., Stephens, A., Browell, E V., Burris, J., McGee, T., and Trepte, C R.: NOGAPS-ALPHA model simulations of stratospheric ozone during the SOLVE2 campaign, Atmos. Chem. Phys., 4, 2401–2423, 2004.
McLinden, C A., Olsen, S C., Hannegan, B., Wild, O., Prather, M J., and Sundet, J.: Stratospheric ozone in 3-D models: A simple chemistry and the cross-tropopause flux, J. Geophys. Res., 105, 14 653–14 665, 2000.
McPeters, R D., Bhartia, P K., Krueger, A J., Herman, J R., Wellemeyer, C G., Seftor, C J., Jaross, G., Torres, O., Moy, L., Labow, G., Byerly, W., Taylor, S L., Swissler, T., and Cebula, R P.: Earth Probe Total Ozone Mapping Spectrometer (TOMS) Data Products User's Guide, NASA Technical Publication 1998-206895, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, 1998.
Massart, S., Cariolle, D., and Peuch, V.-H.: Towards an improvement of the atmospheric ozone distribution and variability by assimilation of satellite data, C. R. Geosciences, 15, 1305–1310, 2005.
Migliorini, S., Piccolo, C., and Rodgers, C D.: Intercomparison of direct and indirect measurements: Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) versus sonde ozone profiles, J. Geophys. Res., 109, D19316, doi:10.1029/2004JD004988, 2004.
Morcrette, J J.: Ozone-radiation interactions in the ECMWF forecast system, ECMWF Technical Memoranda, 375, 2003.
Pawson, S., Kodera, K., Hamilton, K., Shepherd, T G., Beagley, S R., Boville, B A., Farrara, J D., Fairlie, T D A., Kitoh, A., Lahoz, W A., Langematz, U., Manzini, E., Rind, D H., Scaife, A A., Shibata, K., Simon, P., Swinbank, R., Takacs, L., Wilson, R J., Al-Saadi, J A., Amodei, M., Chiba, M., Coy, L., de Grandpré, J., Eckman, R S., Fiorino, M., Grose, W L., Koide, H., Koshyk, J N., Li, D., Lerner, J., Mahlman, J D., McFarlane, N A., Mechoso, C R., Molod, A., O'Neill, A., Pierce, R B., Randel, W J., Rood, R B., and Wu, F.: The GCM-Reality Intercomparison Project for SPARC (GRIPS): Scientific Issues and Initial Results, Bull. Am. Met. Soc., 81, 781–796, 2000.
Peuch, A., Thépaut, J.-N., and Pailleux, J.: Dynamical impact of total-ozone observations in a four-dimensional variational assimilation, Q. J. R. Meteorol. Soc., 126, 1641–1659, 2000.
Plumb, R A.: Stratospheric transport, J. Meteorol. Soc. Jpn., 80, 793–809, 2002.
Rabier, F., Jarvinen, H., Klinker, E., Mahfouf, J. F., and Simmons, A.: The ECMWF operational implementation of four-dimensional variational assimilation. I: Experimental results with simplified physics, Q. J. R. Meteorol. Soc., 126, 1148–1170, 2000.
Randel, W., Udelhofen, P., Fleming, E., Geller, M., Gelman, M., Hamilton, K., Karoly, D., Ortland, D., Pawson, S., Swinbank, R., Wu, F., Baldwin, M., Chanin, M L., Keckhut, P., Labitzke, K., Remsberg, E., Simmons, A., and Wu, D.: The SPARC intercomparison of middle-atmosphere climatologies, J. Climate, 17, 986–1003, 2004.
Raspollini P., Belotti C., Burgess A., Carli B., Carlotti M., Ceccherini S., Dinelli B M., Dudhia A., Flaud J.-M., Funke B., Höpfner M., Lopez-Puertas M., Payne V., Piccolo C., Remedios J J., Ridolfi M., and Spang R.: MIPAS level 2 operational analysis, Atmos. Chem. Phys. Discuss., 6, 6525–6585, 2006.
Riish\ojgaard, L P.: On four-dimensional variational assimilation of ozone data in weather-prediction models, Q. J. R. Meteorol. Soc., 122, 1545–1571, 1996.
Rodgers, C D.: Inverse Methods for Atmospheric Sounding: Theory and Practice, World Scientific Publishing, Singapore, 2000.
Roelofs, G J., Kentarchos, A S., Trickl, T., Stohl, A., Collins, W J., Crowther, R A., Hauglustaine, D., Klonecki, A., Law, K S., Lawrence, M G., von Kuhlmann, R., and van Weele, M.: Intercomparison of tropospheric ozone models: Ozone transport in a complex tropopause folding event, J. Geophys. Res., 108, 8529, doi:10.1029/2003JD003462, 2003.
Russell, J M., Gordley, L L., Park, J H., Drayson, S R., Hesketh, W D., Cicerone, R J., Tuck, A F., Frederick, J E., Harries, J E., and Crutzen, P J.: The Halogen Occultation Experiment, J. Geophys. Res., 98, 10 777–10 797, 1993.
Sassi, F., Boville, B A., Kinnison, D., and Garcia, R R.: The effects of interactive ozone chemistry on simulations of the middle atmosphere, Geophys. Res. Lett., 32, L07811, doi:10.1029/2004GL022131, 2005.
Scheele, M P., Siegmund, P C., and van Velthoven, P F J.: Stratospheric age of air computed with trajectories based on various 3-D-Var and 4-D-Var data sets, Atmos. Chem. Phys., 5, 1–7, 2005.
Schoeberl, M R., Douglass, A R., Zhu, Z X., and Pawson, S.: A comparison of the lower stratospheric age spectra derived from a general circulation model and two data assimilation systems, J. Geophys. Res., 108, 4113, doi:10.1029/2002JD002652, 2003.
Segers, A J., Eskes, H J., Van Der A, R J., Van Oss, R F., and Van Velthoven, P F J.: Assimilation of GOME ozone profiles and a global chemistry transport model using a Kalman filter with anisotropic covariance, Q. J. R. Meteorol. Soc., 131, 477–502, 2005a.
Segers, A J., Von~Savigny, C., Brinksma, E J., and Piters, A J M.: Validation of IFE-1.6 SCIAMACHY limb ozone profiles, Atmos. Chem. Phys., 5, 3045–3052, 2005b.
Spiegel, M R. and Stephens, L J.: Schaum's Outline of Theory and Problems of Statistics, 3rd Ed., McGraw-Hill, New York, 538pp., 1999.
\uStajner, I., Riish\ojgaard , L P., and Rood, R B.: The GEOS ozone data assimilation system: Specification of error statistics, Q. J. R. Meteorol. Soc., 127, 1069–1094, 2001.
\uStajner, I., Winslow, N., Rood, R B., and Pawson, S.: Monitoring of observation errors in the assimilation of satellite ozone data, J. Geophys. Res., 109, D06309, doi:10.1029/2003JD004118, 2004.
Stohl, A., Cooper, O R., and James, P.: A cautionary note on the use of meteorological analysis fields for quantifying atmospheric mixing, J. Atmos. Sci., 61, 1446–1453, 2004.
Struthers, H., Brugge, R., Lahoz, W A., O'Neill, A., and Swinbank, R.: Assimilation of ozone profiles and total column measurements into a global general circulation model, J. Geophys. Res., 107, 4438, doi:10.1029/2001JD000957, 2002.
Talagrand, O.: A posteriori validation of assimilation algorithms, Data Assimilation for the Earth System, edited by: Swinbank, R., Shutyaev, V., and Lahoz, W. A., Kluwer Academic Publications, Dordrecht, The Netherlands, 85–95, 2003.
Tan, W W., Geller, M A., Pawson, S., and da Silva, A.: A case study of excessive subtropical transport in the stratosphere of a data assimilation system, J. Geophys. Res., 109, D11102, doi:10.1029/2003JD004057, 2004.
Thompson, A M., Witte, J C., McPeters, R D., Oltmans, S J., Schmidlin, F J., Logan, J A., Fujiwara, M., Kirchhoff, V W J H., Posny, F., Coetzee, G J R., Hoegger, B., Kawakami, S., Ogawa, T., Johnson, B J., Vomel, H., and Labow, G.: Southern Hemisphere Additional Ozonesondes (SHADOZ) 1998–2000 tropical ozone climatology – 1. Comparison with Total Ozone Mapping Spectrometer (TOMS) and ground-based measurements, J. Geophys. Res., 108, 8238, doi:10.1029/2001JD000967, 2003a.
Thompson, A M., Witte, J C., Oltmans, S J., Schmidlin, F J., Logan, J A., Fujiwara, M., Kirchhoff, V W J H., Posny, F., Coetzee, G J R., Hoegger, B., Kawakami, S J., Ogawa, T., Fortuin, J P F., and Kelder, H M.: Southern Hemisphere Additional Ozonesondes (SHADOZ) 1998–2000 tropical ozone climatology – 2. Tropospheric variability and the zonal wave-one, J. Geophys. Res., 108, 8241, doi:10.1029/2002JD002241, 2003b.
Uppala, S M., Kållberg, P W., Simmons, A J., Andrae, U., da Costa Bechtold, V., Fiorino, M., Gibson, J K., Haseler, J., Hernandez, A., Kelly, G A., Li, X., Onogi, K., Saarinen, S., Sokka, N., Allan, R P., Andersson, E., Arpe, K., Balmaseda, M A., Beljaars A C M., Van De Berg, L., Bidlot, J., Bormann, N., Caires, S., Chevallier, F., Dethof, A., Dragosavac, M., Fisher, M., Fuentes, M., Hagemann, S., Hólm, E., Hoskins, B J., Isaksen, L., Janssen, P A E M., Jenne, R., McNally, A P., Mahfouf, J-F., Morcrette, J-J., Rayner, N A., Saunders, R W., Simon, P., Sterl, A., Trenberth, K E., Untch, A., Vasiljevic, D., Viterbo, P., and Woollen, J.: The ERA-40 re-analysis, Q. J. R. Meteorol. Soc., 131, 2961–3012, 2005.
Wargan, K., \uStajner, I., Pawson, S., and Rood, R B.: Monitoring and Assimilation of Ozone Data from the Michelson Interferometer for Passive Atmospheric Sounding, Q. J. R. Meteorol. Soc., 131, 2713–2734, 2005.
Weaver, A. and Courtier, P.: Correlation modelling on the sphere using a generalized diffusion equation, Q. J. R. Meteorol. Soc., 127, 1815–1846, 2001.
World Meteorological Organisation: Scientific assessment of ozone depletion: 2002, Global Ozone Research and Monitoring Project-Report No. 47, 498 pp., Geneva, 2003.
\uZagar, N.: Assimilation of equatorial waves by line-of-sight wind observations, J. Atmos. Sci., 61, 1877–1893, 2004.