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Observation Operators for the Assimilation of Occultation Data Into Atmospheric Models: A Review

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Atmosphere and Climate

Abstract

During the past decade, researchers have been working to develop methods for the assimilation of Global Positioning System (GPS) radio occultation data into numerical weather prediction (NWP) models. Until recently, two strategies have received the most attention: 1) assimilation of the retrieved bending angle profiles, and 2) assimilation of the retrieved refractivity profiles. The assimilation of retrieved bending angle profiles, e.g., via a ray tracing model, has the advantage that horizontal refractivity gradients, affecting the observations, can be accounted for. However, accurate computation of ray paths through a NWP model is very time consuming in an operational system, and approximations to the ray tracing have to be made. In contrast, the assimilation of retrieved refractivity profiles, interpreted as being representative of the local vertical structure in the atmosphere (also known as assimilation of local refractivity), is simple and fast, but this approach does not account for the influence of the horizontal gradients. Recently, some new observation operators have been developed which are both fast and, to a large degree, capable of taking into account the influence of the horizontal gradients. These new observation operators rely on predefined ray trajectories, and could also become useful for future assimilation of other kinds of occultation data, e.g., ionospheric GPS occultation data, absorption data from low earth orbit constellations, or data from solar/stellar occultation experiments. In this review, a brief account of past and present efforts to develop efficient observation operators for the assimilation of GPS occultation data into atmospheric models will be given, ranging from early suggestions to the recently developed observation operators.

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References

  1. Ahmad B (1998) Accuracy and resolution of atmospheric profiles obtained from radio occultation measurements. PhD thesis, Center for Radar Astronomy, Stanford University, California

    Google Scholar 

  2. Ahmad B, Tyler GL (1998) The two-dimensional resolution kernel associated with retrieval of ionospheric and atmospheric refractivity profiles by Abelian inversion of radio occultation phase data. Radio Sci 33:129–142

    Article  Google Scholar 

  3. Amstrup B, Mogensen KS, Huang XY (2000) Use of GPS observations in an optimum interpolation based data assimilation system. Scientific Report 00-14, Danish Meteorological Institute, Copenhagen, Denmark

    Google Scholar 

  4. Collard AD, Healy SB (2003) The combined impact of future space-based atmospheric sounding instruments on numerical weather-prediction analysis fields: A simulation study. Quart J Roy Meteorol Soc 129:2741–2760

    Article  Google Scholar 

  5. Danmarks Meteorologiske Institut (2003) SAF Training Workshop: 2nd GRAS SAF User Workshop, EUMETSAT, Darmstadt, Germany

    Google Scholar 

  6. Eyre JR (1994) Assimilation of radio occultation measurements into a numerical weather prediction system. Technical Memorandum No 199, European Centre for Medium-Range Weather Forecasts

    Google Scholar 

  7. Eyre JR (1997) Variational assimilation of remotely-sensed observations of the atmosphere. J Meteorol Soc Japan 75:331–338

    Google Scholar 

  8. Fjeldbo G, Kliore AJ, Eshleman VR (1971) The neutral atmosphere of Venus as studied with the Mariner V radio occultation experiments. Astron J 76:123–140

    Article  Google Scholar 

  9. Foelsche U, Kirchengast G (2004) Sensitivity of GNSS occultation profiles to horizontal variability in the troposphere: A simulation study. In: Kirchengast G, Foelsche U, Steiner AK (eds) Occultations for Probing Atmosphere and Climate, Springer, Berlin, pp:127–136

    Google Scholar 

  10. Gobiet A, Kirchengast G (2004) Advancements of Global Navigation Satellite System radio occultation retrieval in the upper stratosphere for optimal climate monitoring utility. J Geophys Res 109:D24110, doi:10.1029/2004JD005117

    Article  Google Scholar 

  11. Gorbunov ME (1996) Three-dimensional satellite refractive tomography of the atmosphere: Numerical simulation. Radio Sci 31:95–104

    Article  Google Scholar 

  12. Gorbunov ME (2002) Ionospheric correction and statistical optimization of radio occultation data. Radio Sci 37:1084, doi:10.1029/2000RS002370

    Article  Google Scholar 

  13. Gorbunov ME, Kornblueh L (2003) Principles of variational assimilation of GNSS radio occultation data. Report No 350, Max-Planck-Institute for Meteorology, Hamburg, Germany

    Google Scholar 

  14. Gorbunov ME, Sokolovskiy SV (1993) Remote sensing of refractivity from space for global observations of atmospheric parameters. Report No 119, Max-Planck-Institute for Meteorology, Hamburg, Germany

    Google Scholar 

  15. Gorbunov ME, Gurvich AS, Bengtson L (1996) Advanced algorithms of inversion of GPS/MET satellite data and their application to reconstruction of temperature and humidity. Report No 211, Max-Planck-Institute for Meteorology, Hamburg, Germany

    Google Scholar 

  16. Gorbunov ME, Sokolovsky SV, Bengtsson L (1996) Space refractive tomography of the atmosphere: Modeling of direct and inverse problems. Report No 210, Max-Planck-Institute for Meteorology, Hamburg, Germany

    Google Scholar 

  17. Healy SB (1998) A statistical comparison of GPS/MET radio occultation data with numerical weather prediction analyses. Technical Report No 247, UK Meteorological Office, Bracknell, UK

    Google Scholar 

  18. Healy SB (2001) Radio occultation bending angle and impact parameter errors caused by horizontal refractive index gradients in the troposphere: A simulation study. J Geophys Res 106:11875–11889

    Article  Google Scholar 

  19. Healy SB (2001) Smoothing radio occultation bending angles above 40 km. Ann Geophys 19:459–468

    Article  Google Scholar 

  20. Healy SB, Eyre JR (2000) Retrieving temperature, water vapour and surface pressure information from refractive-index profiles derived by radio occultation: A simulation study. Quart J Roy Meteorol Soc 126:1661–1683

    Article  Google Scholar 

  21. Healy SB, Thépaut JN (2005) Assimilation experiments with CHAMP GPS radio occultation measurements. Quart J Roy Meteorol Soc (in press)

    Google Scholar 

  22. Healy SB, Jupp AM, Offiler D, Eyre J (2003) The assimilation of radio occultation measurements. In: Reigber C, Lühr H, Schwintzer P (eds) First CHAMP Mission Results for Gravity, Magnetic and Atmospheric Studies, Springer, Berlin pp:453–461

    Google Scholar 

  23. Healy SB, Jupp AM, Marquardt C (2005) Forecast impact experiment with GPS radio occultation measurements. Geophys Res Lett 32:L03804, doi:10.1029/2004GL020806

    Article  Google Scholar 

  24. Huang XY (2000) Variational analysis using spatial filters. Mon Weather Rev 128:2588–2600

    Article  Google Scholar 

  25. Huang XY, Vedel H (2003) An introduction to data assimilation. In: SAF Training Workshop: 2nd GRAS SAF User Workshop, EUMETSAT, Darmstadt, Germany, 25–37

    Google Scholar 

  26. Kuo YH, Zou X, Huang W (1997) The impact of Global Positioning System data on the prediction of an extratropical cyclone: an observing system simulation experiment. Dynam Atmos Oceans 27:439–470

    Article  Google Scholar 

  27. Kuo YH, Sokolovskiy SV, Anthes RA, Vandenberghe F (2000) Assimilation of GPS radio occultation data for numerical weather prediction. Terrestrial, Atmospheric and Oceanic Sciences 11:157–186

    Google Scholar 

  28. Kuo YH, Wee TK, Sokolovskiy S, Rocken C, Schreiner W, Hunt D, Anthes RA (2004) Inversion and error estimation of GPS radio occultation data. J Meteorol Soc Japan 82:507–531

    Article  Google Scholar 

  29. Kursinski ER, Hajj GA, Schofield JT, Linfield RP, Hardy KR (1997) Observing Earth’s atmosphere with radio occultation measurements using the Global Positioning System. J Geophys Res 102:23429–23465

    Article  Google Scholar 

  30. Kursinski ER, Healy SB, Romans LJ (2000) Initial results of combining GPS occultations with ECMWF global analyses within a 1DVar framework. Earth Planets Space 52:885–892

    Google Scholar 

  31. Lee LC, Rocken C, Kursinski R (eds) (2000) Applications of Constellation Observing System for Meteorology, Ionosphere & Climate. Springer, Hong Kong

    Google Scholar 

  32. Liu H, Zou X, Shao H, Anthes RA, Chang JC, Tseng JH, Wang B (2001) Impact of 837 GPS/MET bending angle profiles on assimilation and forecasts for the period June 20–30, 1995. J Geophys Res 106:31771–31786

    Article  Google Scholar 

  33. Liu H, Zou X (2003) Improvements to a GPS radio occultation ray-tracing model and their impacts on assimilation of bending angle. J Geophys Res 108:4548, doi:10.1029/2002JD003160

    Article  Google Scholar 

  34. Lohmann MS (2005) Application of dynamical error estimation for statistical optimization of radio occultation bending angles. Radio Sci 40:RS3011, doi:10.1029/2004RS003117

    Article  Google Scholar 

  35. Lorenc AC (1986) Analysis methods for numerical weather prediction. Quart J Roy Meteorol Soc 112:1177–1194

    Article  Google Scholar 

  36. Marquardt C, Eyre JR, Healy SB, Jupp A, Offiler D (2003) Use of GPS radio occultation data in meteorological services. In: Stauning P, Lühr H, Ultré-Guérard P, LaBrecque J, Purucker M, Primdahl F, Jørgensen JL, Christiansen F, Høeg P, Lauritsen KB (eds) OIST-4 Proceedings, 4’th Oersted International Science Team Conference, Narayana Press, Denmark, 261–268

    Google Scholar 

  37. Palmer PI, Barnett JJ, Eyre JR, Healy SB (2000) A nonlinear optimal, estimation inverse method for radio occultation measurements of temperature, humidity, and surface pressure. J Geophys Res 105:17513–17526

    Article  Google Scholar 

  38. Poli P (2003) A fast forward model for simulating GPS radio occultation bending angles and refractivity in a two dimensional plane: Implementation and simulations. In: SAF Training Workshop: 2nd GRAS SAF User Workshop, EUMETSAT, Darmstadt, Germany, 38–48

    Google Scholar 

  39. Poli P (2004) Effects of horizontal gradients on GPS radio occultation observation operators. II: A Fast Atmospheric Refractivity Gradient Operator (FARGO). Quart J Roy Meteorol Soc 130:2807–2825

    Article  Google Scholar 

  40. Poli P, Joiner J (2003) Assimilation experiments of one-dimensional variational analyses with GPS/MET refractivity. In: Reigber C, Lühr H, Schwintzer P (eds) First CHAMP Mission Results for Gravity, Magnetic and Atmospheric Studies, Springer, Berlin, pp:515–520

    Google Scholar 

  41. Poli P, Joiner J (2004) Effects of horizontal gradients on GPS radio occultation observation operators. I: Ray tracing. Quart J Roy Meteorol Soc 130:2787–2805

    Article  Google Scholar 

  42. Poli P, Joiner J, Kursinski ER (2002) 1DVAR analysis of temperature and humidity using GPS radio occultation refractivity data. J Geophys Res 107:4448, doi:10.1029/2001JD000935

    Article  Google Scholar 

  43. Rhodin A (2003) Assimilation of radio occultation data at DWD. In: SAF Training Workshop: 2nd GRAS SAF User Workshop, EUMETSAT, Darmstadt, Germany, 80–84

    Google Scholar 

  44. Rieder MJ, Kirchengast G (2001) Error analysis and characterization of atmospheric profiles retrieved from GNSS occultation data. J Geophys Res 106:31755–31770

    Article  Google Scholar 

  45. Rubek F, Sørensen MB (2003) GRAS-SAF system, products, and archive. In: SAF Training Workshop: 2nd GRAS SAF User Workshop, EUMETSAT, Darmstadt, Germany, 60–72

    Google Scholar 

  46. Schlatter TW (2000) Variational assimilation of meteorological observations in the lower atmosphere: a tutorial on how it works. J Atmos Solar-Terr Phys 62:1057–1070

    Article  Google Scholar 

  47. Shao H, Zou X (2002) The impact of observational weighting on the assimilation of GPS/MET bending angle. J Geophys Res 107:4717, doi:10.1029/2001JD001552

    Article  Google Scholar 

  48. Smith EK, Weintraub S (1953) The constants in the equation for atmospheric refractive index at radio frequencies. Journal of Research of the National Bureau of Standards 50:39–41

    Google Scholar 

  49. Sokolovskiy S, Kuo YH, Wang W (2004) Evaluation of a linear phase observation operator with CHAMP radio occultation data and high-resolution regional analysis. Mon Weather Rev (in press)

    Google Scholar 

  50. Sokolovskiy S, Kuo YH, Wang W (2005) Assessing the accuracy of a linearized observation operator for assimilation of radio occultation data: case simulations with a high-resolution weather model. Mon Weather Rev 133:2200–2212

    Article  Google Scholar 

  51. Sokolovskiy SV (2001) Tracking tropospheric radio occultation signals from low Earth orbit. Radio Sci 36:483–498

    Article  Google Scholar 

  52. Steiner AK, Kirchengast G (2004) Ensemble-based analysis of errors in atmospheric profiles retrieved from GNSS occultation data. In: Kirchengast G, Foelsche U, Steiner AK (eds) Occultations for Probing Atmosphere and Climate, Springer, Berlin, pp:149–160

    Google Scholar 

  53. Syndergaard S (1999) Retrieval analysis and methodologies in atmospheric limb sounding using the GNSS radio occultation technique. Scientific Report 99-6, Danish Meteorological Institute, Copenhagen, Denmark

    Google Scholar 

  54. Syndergaard S, Flittner D, Kursinski R, Herman B (2003) Simulating the influence of horizontal gradients on refractivity profiles from radio occultations. In: Stauning P, Lühr H, Ultré-Guérard P, LaBrecque J, Purucker M, Primdahl F, Jørgensen JL, Christiansen F, Høeg P, Lauritsen KB (eds) OIST-4 Proceedings, 4’th Oersted International Science Team Conference, Narayana Press, Denmark, 245–250

    Google Scholar 

  55. Syndergaard S, Flittner DE, Kursinski ER, Feng DD, Herman BM, Ward DM (2004) Simulating the influence of horizontal gradients on retrieved profiles from ATOMS occultation measurements-a promising approach for data assimilation. In: Kirchengast G, Foelsche U, Steiner AK (eds) Occultations for Probing Atmosphere and Climate, Springer, 221–232

    Google Scholar 

  56. Syndergaard S, Kursinski ER, Herman BM, Lane EM, Flittner DE (2005) A refractive index mapping operator for assimilation of occultation data. Mon Weather Rev 133:2650–2668

    Article  Google Scholar 

  57. von Engeln A, Nedoluha G (2005) Retrieval of temperature and water vapor profiles from radio occultation refractivity and bending angle measurements using an optimal estimation approach: a simulation study. Atmospheric Chemistry and Physics 5:1665–1677

    Article  Google Scholar 

  58. von Engeln A, Nedoluha G, Kirchengast G, Bühler S (2003) One-dimensional variational (1-D Var) retrieval of temperature, water vapor, and a reference pressure from radio occultation measurements: A sensitivity analysis. J Geophys Res 108:4337, doi:10.1029/2002JD002908

    Article  Google Scholar 

  59. Wee TK, Kuo YH (2004) Impact of a digital filter as a weak constraint in MM5 4DVAR: An observing system simulation experiment. Mon Weather Rev 132:543–559

    Article  Google Scholar 

  60. Zhang X, Liu Y, Wang B, Ji Z (2004) Parallel computing of a variational data assimilation model for GPS/MET observation using the ray-tracing method. Advances in Atmospheric Sciences 21:220–226

    Article  Google Scholar 

  61. Zou X, Kuo YH, Guo YR (1995) Assimilation of atmospheric radio refractivity using a nonhydrostatic adjoint model. Mon Weather Rev 123:2229–2249

    Article  Google Scholar 

  62. Zou X, Vandenberghe F, Wang B, Gorbunov ME, Kuo YH, Sokolovskiy S, Chang JC, Sela JG, Anthes RA (1999) A raytracing operator and its adjoint for the use of GPS/MET refraction angle measurements. J Geophys Res 104:22301–22318

    Article  Google Scholar 

  63. Zou X, Wang B, Liu H, Anthes RA, Matsumura T, Zhu YJ (2000) Use of GPS/MET refraction angles in three-dimensional variational analysis. Quart J Roy Meteorol Soc 126:3013–3040

    Article  Google Scholar 

  64. Zou X, Liu H, Anthes RA (2002) A statistical estimate of errors in the calculation of radio-occultation bending angles caused by a 2D approximation of ray tracing and the assumption of spherical symmetry of the atmosphere. J Atmos Ocean Technol 19:51–64

    Article  Google Scholar 

  65. Zou X, Liu H, Anthes RA, Shao H, Chang JC, Zhu YJ (2004) Impact of CHAMP radio occultation observations on global analysis and forecasts in the absence of AMSU radiance data. J Meteorol Soc Japan 82:533–549

    Article  Google Scholar 

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Authors and Affiliations

  1. COSMIC Project Office, University Corporation for Atmospheric Research, Boulder, CO, USA

    S. Syndergaard, Y.-H. Kuo & M. S. Lohmann

  2. Joint Center for Satellite Data Assimilation, NOAA/NESDIS, Camp Springs, MD, USA

    M. S. Lohmann

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  1. S. Syndergaard
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  2. Y.-H. Kuo
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Editors and Affiliations

  1. Wegener Center for Climate and Global Change (WegCenter), University of Graz, Leechgasse 25, 8010, Graz

    Ulrich Foelsche , Gottfried Kirchengast  & Andrea Steiner ,  & 

  2. Institute for Geophysics, Astrophysics, and Meteorology (IGAM), University of Graz, Universitätsplatz 5, 8010, Graz, Austria

    Ulrich Foelsche , Gottfried Kirchengast  & Andrea Steiner ,  & 

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Syndergaard, S., Kuo, YH., Lohmann, M.S. (2006). Observation Operators for the Assimilation of Occultation Data Into Atmospheric Models: A Review. In: Foelsche, U., Kirchengast, G., Steiner, A. (eds) Atmosphere and Climate. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-34121-8_18

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