Start Submission Become a Reviewer

Reading: An observation operator for ground-based GPS slant delays

Download

A- A+
Alt. Display

Original Research Papers

An observation operator for ground-based GPS slant delays

Authors:

Reima Eresmaa,

Finnish Meteorological Institute, Vuorikatu 24, FIN-00100 Helsinki, FI
X close

Heikki Järvinen

Finnish Meteorological Institute, Vuorikatu 24, FIN-00100 Helsinki, FI
X close

Abstract

An observation operator for the Global Positioning System (GPS) Slant Total Delay (STD) observations is developed. The operator is implemented in the High Resolution Limited Area Model (HIRLAM) for data assimilation of tropospheric humidity information contained in the geodetic estimates of microwave signal phase delays.

The observation operator integrates refractivity along the signal path between the satellite and the receiver to obtain STD. The signal path is solved using the geometrical path, as given by the geometrical azimuth and zenith angles of the satellite as viewed at the receiver, as the starting point. The tropospheric effect on the signal path is accounted for.

A preliminary validation of the operator has been performed against observational data. Model counterparts are compared with the geodetic estimates of Zenith Total Delay (ZTD) and STD. The bias and standard deviation between modelled and observed STD are −1.0 and 1.7 cm, respectively, at zenith, and −7.2 and 8.6 cm, respectively, at zenith angle 80°.

How to Cite: Eresmaa, R. and Järvinen, H., 2006. An observation operator for ground-based GPS slant delays. Tellus A: Dynamic Meteorology and Oceanography, 58(1), pp.131–140. DOI: http://doi.org/10.1111/j.1600-0870.2006.00154.x
  Published on 01 Jan 2006
 Accepted on 22 Aug 2005            Submitted on 10 Dec 2004

References

  1. Alber , C. , Ware , R. , Rocken , C. and Braun , J. 2000 . Obtaining single path phase delays from GPS double differences . Geophys. Res. Lett . 27 , 2661 – 2664 .  

  2. Andersson , E. , Pailleux , J. , Thepaut , J.-N. , Eyre , J. R. , McNally , A. P. and co-authors. 1994 . Use of cloud-cleared radiances in three/four-dimensional variational data assimilation . Q. J. R. MeteoroL Soc . 120 , 627 – 653 .  

  3. Bevis , M. , Businger , S. , Chiswell , S. , Herring , T. A. , Anthes , R. A. and co-authors. 1994 . GPS meteorology: Mapping zenith wet delays onto precipitable water . J. AppL MeteoroL 33 , 379 – 386 .  

  4. Bevis , M. , Businger , S. , Herring , T. , Rocken , C. , Anthes , R. and co-authors. 1992 . GPS meteorology: Remote sensing of atmospheric water vapor using the Global Positioning System . J. Geophys. Res . 97 ( D14 ), 15787 – 15801 .  

  5. Braun , J. , Rocken , C. and Ware , R. 2001 . Validation of line-of-sight water vapor measurements with GPS . Radio Sc i . 36 , 459 – 472 .  

  6. de Haan , S. , van der Marel , H. and Barlag , S. 2002 . Comparison of GPS slant delay measurements to a numerical model: Case study of a cold front passage . Phys. Chem. Earth (A/13/C ) 27 , 317 – 322 .  

  7. De Pondeca , M. and Zou , X. 2001 . A case study of the variational as-similation of GPS zenith delay observations into a mesoscale model . J. AppL MeteoroL 40 , 1559 – 1576 .  

  8. Elosegui , P. and Davis , J. 2004 . Accuracy assessment of GPS slant-path determinations. In: Proceedings of the International Workshop on GPS Meteorology, Tsukuba, Japan, 14-17 Jan 2003 (eds. T. Iwabuchi and Y. Shoji ).  

  9. Eresmaa , R. and Järvinen , H. 2005 . Estimation of spatial GPS Zenith Delay observation error covariance . Tellus 57A , 194 – 203 .  

  10. Guo , Y.-R. , Kuo , Y.-H. , Dudhia , J. and Parsons , D. 2000 . Four-dimensional variational data assimilation of heterogeneous mesoscale observations for a strong convective case. Mon. Weather Re v . 128 , 619 – 643 .  

  11. Gustafsson , N. 2002 . Assimilation of ground-based GPS data in HIRLAM 3D-Var. In: Proceedings of the HIRLAM Workshop on Variational Data Assimilation and Remote Sensing, Finnish Mete-orological Institute, Helsinki 21-23 Jan 2002, 89-96. Available from the HIRLAM Project, do Per Unden, SMHI, S-60176 Norrkoping, Sweden.  

  12. Gustafsson , N. , Berre , L. , Hörnquist , S. , Huang , X.-Y. , Lindskog , M. and co-authors. 2001. Three-dimensional variational data assimilation for a limited area model. Part I: General formulation and the background error constraint. Tellus 53A , 425 – 446 .  

  13. Ha , S.-Y. , Kuo , Y.-H. , Guo , Y.-R. and Lim , G.-H. 2003 . Variational assimilation of slant path wet delay measurements from a hy-pothetical ground-based GPS network. Part I: Comparison with precipitable water assimilation. Mon. Weather Re v . 131 , 2635 – 2655 .  

  14. Haase , J. , Ge , M. , Vedel , H. and Calais , E. 2003 . Accuracy and variability of GPS tropospheric delay measurements of water vapor in the Western Mediterranean . J. AppL MeteoroL 42 , 1547 – 1568 .  

  15. Healy , S. 2001 . Radio occultation bending angle and impact parame-ter errors caused by horizontal refractive index gradients in the tro-posphere: A simulation study . J. Geophys. Res ., 106 ( D11 ), 11 857 – 11889 .  

  16. Higgins , M. 2001 . Progress in 3D-variational assimilation of total zenith delay . Phys. Chem. Earth (A) 26 , 445 – 449 .  

  17. Hofmann-Wellenhof , B. , Lichtenegger , H. and Collins , J. 2001 . GPS. Theory and practice 5th Edition . Springer, New York, ISBN 3-211-83534-2 , 384 pp .  

  18. Kuo , Y.-H. , Zou , X. and Guo , Y.-R. 1996 . Variational assimilation of precipitable water using a nonhydrostatic mesoscale adjoint model. Part I: Moisture retrieval and sensitivity experiments . Mon. Weather Rev . 124 , 122 – 147 .  

  19. Lindskog , M. , Gustafsson , N. , Navascues , B. , Mogensen , K. S., Huang , X.-Y. and co-authors . 2001. Three-dimensional variational data as-similation for a limited area model. Part H: Observation handling and assimilation experiments. Tellus 53A , 447 – 468 .  

  20. Lorene , A. C. 1986 . Analysis methods for numerical weather prediction . Q. J. R. Meteorol. Soc . 112 , 1177 – 1194 .  

  21. McClatchey , R. A. , Fenn , R. W. , Selby , J. E. A. , Volz , F. E. and Garing , J. S. 1971 . Optical properties of the atmosphere. Report AFCRL-71-0279, Air Force Cambridge Research Laboratories . Available from Air Force Geophysics Laboratory, Hanscom Air Force Base, MA 01731, USA , 85 pp .  

  22. Majewslci , D. 1985 . Balanced initial and boundary values for a limited area model . Beitr. Phys. Atmos . 58 , 147 – 159 .  

  23. Niell , A. 1996 . Global mapping functions for the atmosphere delay at radio wavelengths . J. Geophys. Res . 101 ( B2 ), 3227 – 3246 .  

  24. Pacione , R. , Sciarretta , C. , Faccani , C. , Ferretti , R. and Vespe , F. 2001 . GPS PW assimilation into MM5 with the nudging technique . Phys. Chem. Earth (A) 26 , 481 – 485 .  

  25. Pacione , R. and Vespe , F. 2003 . GPS zenith total delay estimation in the Mediterranean area for climatological and meteorological appli-cations . J. Atmos. Oceanic TechnoL 20 , 1034 – 1042 .  

  26. Pany , T. 2002 . Measuring and modeling the slant wet delay with GPS and the ECMWF NWP model . Phys. Chem. Earth (A/13/C) 27 , 347 – 354 .  

  27. Poli , P. and Joiner , J. 2004 . Effects of horizontal gradients on GPS radio occultation observation operators. I: Ray tracing . Q. J. R. Meteorol. Soc . 130 , 2787 – 2805 .  

  28. Saastamoinen , J. 1972 . Atmospheric correction for the troposphere and stratosphere in radio ranging of satellites. In: The Use of Artificial Satellites for Geodesy Volume 15 , (eds. S. W. Henriksen et al.) Geo-phys. Monogr. Ser., AGU , 247 – 251 .  

  29. Simmons , A. J. and Burridge , D. M. 1981 . An energy and angular mo-mentum conserving vertical finite difference scheme and hybrid ver-tical coordinates . Mon. Weather Rev . 109 , 758 – 766 .  

  30. Stoew , B. and Elgered , G. 2004 . Characterization of atmospheric param-eters using a ground based GPS network in North Europe . J. Meteorol. Soc. Jpn . 58 ( 1B ), 587 – 596 .  

  31. Stoew , B. , Jarlemark , P. , Johansson , J. and Elgered , G. 2001 . Real-time processing of GPS data delivered by SWEPOS . Phys. Chem. Earth (A) 26 , 493 – 496 .  

  32. Und´en , P. , Rontu , L., Järvinen , H. , Lynch , P. , Calvo , J. and co-authors . 2002 . HIRLAM-5 Scientific Documentation. Available from Hirlam-5 Project, do Per Unden, SMHI, S-60176, Norrkoping, Sweden , 144 pp .  

  33. Ware , R. , Alber , C. , Rocken , C. and Solheim , F. 1997 . Sensing integrated water vapor along GPS ray paths . Geophys. Res. Lett . 24 , 417 – 420 .  

  34. Zou , X. , Vandenberghe , F. , Wang , B. , Gorbunov , M. E., Kuo , Y.-H. and co-authors. 1999 . A ray-tracing operator and its adjoint for the use of GPS/MET refraction angle measurements. J. Geophys. Res . 104 ( D18 ), 22301 – 22318 .  

comments powered by Disqus