Content of presentation

1. Retrieval Analysis and Methodologies in Atmospheric Limb Sounding Using the GNSS Radio Occultation Technique PhD Defence by Stig Syndergaard

2. Content of presentation • The GNSS radio occultation principle • Data processing and exemplar results • ----------------------------------------------- • Violation of spherical symmetry assumption • Severe weather gradients • Earth’s oblateness • Ionosphere calibration of data • Conclusion and prospects

3. The GPS constellation • 24 satellites • Six 12 hour orbits • Altitude: 20200 km • Inclination: 55º • Transmit dual frequency signals

8. Content of presentation • The GNSS radio occultation principle • Data processing and exemplar results • ----------------------------------------------- • Violation of spherical symmetry assumption • Severe weather gradients • Earth’s oblateness • Ionosphere calibration of data • Conclusion and prospects

13. Content of presentation • The GNSS radio occultation principle • Data processing and exemplar results • ----------------------------------------------- • Violation of spherical symmetry assumption • Severe weather gradients • Earth’s oblateness • Ionosphere calibration of data • Conclusion and prospects

18. Content of presentation • The GNSS radio occultation principle • Data processing and exemplar results • ----------------------------------------------- • Violation of spherical symmetry assumption • Severe weather gradients • Earth’s oblateness • Ionosphere calibration of data • Conclusion and prospects

19. Correcting for the Earth’s oblateness

20. Earth’s oblateness Before correction After correction

21. Content of presentation • The GNSS radio occultation principle • Data processing and exemplar results • ----------------------------------------------- • Violation of spherical symmetry assumption • Severe weather gradients • Earth’s oblateness • Ionosphere calibration of data • Conclusion and prospects

24. Model calculation of retrievals of the temperature in the case of a typical day-time, solar maximum ionosphere

31. GPS/MET occultation no. 259, day 35, 1997

33. Content of presentation • The GNSS radio occultation principle • Data processing and exemplar results • ----------------------------------------------- • Violation of spherical symmetry assumption • Severe weather gradients • Earth’s oblateness • Ionosphere calibration of data • Conclusion and prospects

37. 14 days of GPS/MET occultations