Summary
The German CHAMP (CHAllenging Minisatellite Payload) satellite provides continuously GPS radio occultation data since February 2001. The measurements are analyzed by an operational satellite orbit and occultation processing system at GFZ. In total, more than 200,000 precise globally distributed vertical profiles of refractivity, temperature and water vapor are provided as of June 2005. The operational ground infrastructure from GFZ allows for the demonstration of a rapid data analysis since February 2003. A mean delay between measurement and provision of atmospheric excess phase data of ∼4 hours is continuously reached. Results of various validation studies with data from meteorological analyzes of the European Centre for Medium-Range Weather Forecasts (ECMWF) and the global radiosonde network indicate an excellent quality of the CHAMP data. But in the lower troposphere systematic deviations are observed, the known negative refractivity bias of the occultation data. It is most pronounced in the Tropics and is also observed by other GPS occultation instruments. The CHAMP data stimulated a number of studies to investigate the observed bias and to improve the GPS occultation data quality in the lower troposphere. First radio occultation measurements from the GRACE-B (Gravity Recovery And Climate Experiment) satellite are available for a 25 h period on July 28/29, 2004.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Ao, C. O., T. K. Meehan, G. A. Hajj, A. J. Mannucci, and G. Beyerle, Lower-troposphere refractivity bias in GPS occultation retrievals, J. Geophys. Res., 108(D18), doi:10.1029/2002JD003,216, 2003a.
Ao, C. O., W. B. Schreiner, and J. Wickert, First report on the CHAMP radio occultation intercomparison study, JPL Publication, 03-016, 2003b.
Beyerle, G., M. E. Gorbunov, and C. O. Ao, Simulation studies of GPS radio occultation measurements, Radio Sci., 38(5), doi:10.1029/2002RS002,800, 2003a.
Beyerle, G., J. Wickert, T. Schmidt, and C. Reigber, Atmospheric sounding by GNSS radio occultation: An analysis of the negative refractivity bias using CHAMP observations, J. Geophys. Res., p. doi:10.1029/2003JD003922, 2003b.
Beyerle, G., T. Schmidt, G. Michalak, J. Wickert, and C. Reigber, GPS radio occultation with GRACE: Atmospheric profiling utilizing the zero difference technique, Geophys. Res. Lett., in print, 2005a.
Beyerle, G., T. Schmidt, J. Wickert, S. Heise, C. Reigber, and G. König-Langlo, An analysis of refractivity biases detected in GPS radio occultation data: Results from simulation studies, aerological soundings and CHAMP satellite observations, paper available via www.arxiv.org/physics/0502052, 2005b.
Dunn, C., et al., Instrument of GRACE-GPS Augments Gravity Measurements, GPS World, Feb. 1, 2003.
Foelsche, U., G. Kirchengast, A. Gobiet, A. Steiner, A. Löscher, J. Wickert, and T. Schmidt, The CHAMPCLIM project: An overview, in Earth Observation with CHAMP: Results from Three Years in Orbit, edited by C. Reigber, P. Schwintzer, H. Lühr, and J. Wickert, pp. 615–620, Springer Verlag, 2005.
Gobiet, A., U. Foelsche, A. Steiner, M. Borsche, G. Kirchengast, and J. Wickert, Validation of stratospheric temperatures in ECMWF operational analyses with CHAMP radio occultation data, Geophys. Res. Lett., 32(12), doi:10.1029/2005GL022,617, 2005.
Hajj, G. A., L. C. Lee, X. Pi, L. J. Romans, W. S. Schreiner, P. R. Straus, and C. Wang, COSMIC GPS ionospheric sensing and space weather, Terrestrial, Atmospheric and Oceanic Science, 11, 2000.
Hajj, G. A., et al., CHAMP and SAC-C atmospheric occultation results and intercomparisons, J. Geophys. Res., 109(D06109), doi:10.1029/2003JD003,909, 2004.
Healy, S., and J. Eyre, Retrieving temperature, water vapor and surface pressure information from refractive-index profiles derived by radio occultation: A simulation study, Quart. J. Roy. Meteorol. Soc., 126, 1661–1683, 2000.
Healy, S., A. Jupp, and C. Marquardt, Forecast impact experiment with gps radio occultation measurements, Geophys. Res. Lett., 32(3), doi: 10.1029/2004GL020,806, 2005.
Healy, S. B., and J.-N. Thepaut, Assimilation experiments with CHAMP GPS radio occultation measurements, Q. J. R. Meteorol. Soc., subm., 2005.
Heise, S., J. Wickert, G. Beyerle, T. Schmidt, and C. Reigber, Global monitoring of tropospheric water vapor with GPS radio occultation aboard CHAMP, Adv. Space Res., in print, 2005.
Jakowski, N., A. Wehrenpfennig, S. Heise, C. Reigber, H. Lühr, L. Grunwaldt, and T. K. Meehan, GPS radio occultation measurements of the ionosphere from CHAMP: Early results, Geophys. Res. Lett., 29(10), doi:10.1029/2002RS002763, 2002.
König, R., G. Michalak, and K. Neumayer, Remarks on champ orbit products, in Observation of the Earth System from Space, edited by R. Rummel, C. Reigber, M. Rothacher, G. Boedecker, U. Schreiber, and J. Flury, Springer Verlag, 2005a.
König, R., G. Michalak, K. Neumayer, R. Schmidt, S. Zhu, H. Meixner, and C. Reigber, Recent developments in CHAMP orbit determination at GFZ, in Earth Observation with CHAMP: Results from Three Years in Orbit, edited by C. Reigber, P. Schwintzer, H. Lühr, and J. Wickert, Springer Verlag, 2005b.
Kuo, Y.-H., S. V. Sokolovskiy, R. A. Anthes, and F. Vandenberghe, Assimilation of GPS radio occultation data for numerical weather prediction, Terrestrial, Atmospheric and Oceanic Sciences, 11(1), 157–186, 2000.
Kuo, Y.-H., T.-K. Wee, S. Sokolovskiy, C. Rocken, W. Schreiner, D. Hunt, and R. A. Anthes, Inversion and error estimation of GPS radio occultation data, J. Meteorol. Soc. Jpn., 1B(82), 507–531, 2004.
Kuo, Y.-H., W. S. Schreiner, J. Wang, D. L. Rossiter, and Y. Zhang, Comparison of GPS Radio occultation soundings with radiosondes, Geophys. Res. Lett., 32, l05817, doi:10.1029/2004GL021443, 2005.
Kursinski, E. R., G. A. Hajj, J. T. Schofield, R. P. Linfield, and K. R. Hardy, Observing Earth’s atmosphere with radio occultation measurements using Global Positioning System, J. Geophys. Res., 19(D19), 23,429–23,465, 1997.
Larsen, G., K. Lauritsen, F. Rubek, and M. Sørensen, Processing of CHAMP radio occultation data using GRAS SAF software, in Earth Observation with CHAMP: Results from Three Years in Orbit, edited by C. Reigber, P. Schwintzer, H. Lühr, and J. Wickert, pp. 543–548, Springer Verlag, 2005.
Loiselet, M., N. Stricker, Y. Menard, and J. Luntama, GRAS — MetOps GPS based atmospheric sounder, ESA Bulletin, May, 102, 38–44, 2000.
Marquardt, C., K. Schöllhammer, G. Beyerle, T. Schmidt, J. Wickert, and C. Reigber, Validation and data quality of CHAMP radio occultation data, in First CHAMP Mission Results for Gravity, Magnetic and Atmospheric Studies, pp. 384–396, Springer Verlag, 2003.
Randel, W. J., F. Wu, and W. R. Rios, Thermal variability of the tropical tropopause region derived from GPS/MET observations, J. Geophys. Res., 108(4024), doi: doi:10.1029/2002JD002595, 2003.
Reigber, C., P. Schwintzer, H. Lühr, and J. Wickert (Eds.), Earth Observation with CHAMP: Results from Three Years in Orbit, Springer Verlag, 2005.
Rocken, C., Y.-H. Kuo, W. Schreiner, D. Hunt, S. Sokolovskiy, and C. McCormick, COSMIC system description, Terrestrial, Atmospheric and Oceanic Sciences, 11, 21–52, 2000.
Rocken, C., et al., Analysis and validation of GPS/MET data in the neutral atmosphere, J. Geophys. Res., 102(D25), 29,849–29,866, 1997.
Sausen, R., and B. Santer, Use of changes in tropopause height to detect human influences on climate, Met. Zeitschrift, 12(3), 131–136, 2003.
Schmidt, T., J. Wickert, G. Beyerle, and C. Reigber, Tropical tropopause parameters derived from GPS radio occultation measurements with CHAMP, J. Geophys. Res., 109(D13105), doi:10.1029/2004JD004566, 2004.
Schmidt, T., S. Heise, J. Wickert, G. Beyerle, and C. Reigber, GPS radio occultation with CHAMP and SAC-C: global monitoring of thermal tropopause parameters, Atmosph. Chemistry and Physics, 5, 1473–1488, 2005a.
Schmidt, T., J. Wickert, G. Beyerle, R. König, R. Galas, and C. Reigber, The CHAMP atmospheric processing system for Radio occultation measurements, in Earth Observation with CHAMP: Results from Three Years in Orbit, edited by C. Reigber, P. Schwintzer, H. Lühr, and J. Wickert, Springer Verlag, 2005b.
Sokolovskiy, S. V., Tracking tropospheric radio occultation signals from low Earth orbit, Radio Sci., 36(3), 483–498, 2001.
Takahashi, H., et al., Scientific satellite EQUARS for remote sensing of the equatorial atmosphere, 7th Latin-American Conference on Space Geophysics, Atibaia, April, 2004.
Tapley, B., and C. Reigber, GRACE (Gravity Recovery and Climate Experiment), in McGraw-Hill Yearbook of Science & Technology, 2004.
Tett, S., et al., Estimation of natural and anthropogenic contributions to twentieth century temperature change, JGR, 107, 4306, 10.1029/2000JD000,028, 2002.
v. Engeln, A., J. Teixeira, J. Wickert, and S. Buehler, Detecting the planetary boundary layer using CHAMP data, Geophys. Res. Lett., 32, doi:10.1029/2004GL022,168, 2005.
Wang, D. Y., et al., Cross-validation of MIPAS/ENVISAT and GPS-RO/CHAMP temperature profiles, J. Geophys. Res., 109, doi:10.1029/2004JD004963, 2004.
Ware, R., et al., GPS sounding of the atmosphere from low Earth orbit: Preliminary results, Bull. Am. Meteorol. Soc., 77(1), 19–40, 1996.
Wickert, J., The CHAMP radio occultation experiment: Algorithms, Processing system, and First results (in German), Scientific Technical Report 02/07, GFZ Potsdam, 2002.
Wickert, J., Comparison of vertical refractivity and temperature profiles from CHAMP with radiosonde measurements, Scientific Technical Report 04/19, GFZ Potsdam, ISSN 1610-0956, 2004.
Wickert, J., A. Pavelyev, Y. A. Liou, T. Schmidt, C. Reigber, A. Pavelyev, K. Igarashi, and S. Matyugov, Amplitude variations in the GPS signals as a possible indicator of the ionospheric structures, Geophys. Res. Lett., 31, l24801, doi:10.1029/2004GL020607, 2004a.
Wickert, J., T. Schmidt, G. Beyerle, R. König, C. Reigber, and N. Jakowski, The radio occultation experiment aboard CHAMP: Operational data processing and validation of atmospheric parameters, J. Meteorol. Soc. Jpn., 82(1B), 381–395, 2004b.
Wickert, J., C. Ao, and W. Schreiner, GPS based atmospheric sounding with CHAMP: Comparison of data analysis and results from GFZ, JPL and UCAR, GFZ Scientific Technical Report, in preparation, Potsdam, 2005a.
Wickert, J., G. Beyerle, R. König, S. Heise, L. Grunwaldt, G. Michalak, C. Reigber, and T. Schmidt, GPS radio occultation with CHAMP and GRACE: A first look at a new and promising satellite configuration for global atmospheric sounding, Ann. Geophysicae, 23(653–658), 2005b.
Wickert, J., T. Schmidt, G. Beyerle, G. Michalak, R. König, S. Heise, and C. Reigber, GPS radio occultation with CHAMP and GRACE: Recent results, in Proc. OPAC-2 workshop, Graz September 2004, edited by G. Kirchengast, U. Foelsche, and A. K. Steiner, Springer Verlag, 2005c.
Wickert, J., et al., Atmosphere sounding by GPS radio occultation: First results from CHAMP, Geophys. Res. Lett., 28(17), 3263–3266, 2001.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2006 Springer-Verlag Berlin Heidelberg
About this chapter
Cite this chapter
Wickert, J., Schmidt, T., Beyerle, G., Heise, S., Reigber, C. (2006). Global Atmospheric Sounding with GPS Radio Occultation aboard CHAMP. In: Flury, J., Rummel, R., Reigber, C., Rothacher, M., Boedecker, G., Schreiber, U. (eds) Observation of the Earth System from Space. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-29522-4_5
Download citation
DOI: https://doi.org/10.1007/3-540-29522-4_5
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-29520-4
Online ISBN: 978-3-540-29522-8
eBook Packages: Earth and Environmental ScienceEarth and Environmental Science (R0)