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GPS Radiooccultation with CHAMP
- The German satellite CHAMP (launch 15 July 2000)
[1]
- © GFZ
The German geoscience satellite CHAMP was launched on
July 15, 2000 from the Russian COSMODROME Plesetsk, Russia (62.50 N,
40.30 E) into an almost circular, near polar orbit with an initial
altitude of 454 km (eccentricity=0.004, inclination=87.2°). The
scientific project was under lead from GFZ. The main goals are the
determination Earth's gravity and magnetic field and the application
of the GPS Radio Occultation (RO) technique for precise atmospheric
sounding on a global scale. The CHAMP satellite burned up in the
Earth's atmosphere in 2010 after an extremely successful mission
period. The scientific data of the entire CHAMP mission are available
at GFZ for the international user community.
The GPS RO
measurements aboard CHAMP were activated for the first time on
February 11, 2001, and indicated already the potential of CHAMP RO
data to significantly improve the GPS occultation technique [5].
Numerous scientific studies related to data processing and the
scientific application of CHAMP's data have proven this during the
following years [1, 2, 6, 7]. Even 3 years after the end of the
mission, CHAMP data are in use by a large number of research groups
throughout the world. The data were and are also used to prepare
several satellite missions with GPS RO capability, as, e.g., COSMIC,
Metop and others. CHAMP was generating the first and unique long-term
set of GPS RO data, which is used for climatological studies [4]. From
2006 until mission end the CHAMP data were also used to improve global
weather forecasts [3]. The base for this application was the near-real
time provision of RO data from CHAMP by GFZ
[7].
References:
[1] Arras C,
Wickert J, Beyerle G, Heise S, Schmidt T, Jacobi C, A global
climatology of ionospheric irregularities derived from GPS radio
occultation. Geophys. Res. Lett., 35, doi; 10.1029/2008GL034158,
2008.
[2] Beyerle G, Schmidt T, Wickert J, Heise S, Rothacher
M, König-Langlo G, Lauritsen K, Observations and simulations of
receiver-induced refractivity biases in GPS radio occultation. J
Geophys Res 111(D12), DOI 10.1029/2005JD006673, 2006.
[3]
Healy S, Wickert J, Michalak G, Schmidt T, Beyerle G, Combined
forecast impact of GRACE-A and CHAMP GPS radio occultation bending
angle profiles. Atm Sci Letters 8:43–50, DOI 10.1002/asl.149,
2007.
[4] Schmidt T, Wickert J, Beyerle G, Heise S, Global
tropopause height trends estimated from GPS radio occultation data.
Geophys Res Lett 35 (L11806), DOI 10.1029/2008GL034012,
2008.
[5] Wickert J, Reigber C, Beyerle G, König R,
Marquardt C, Schmidt T, Grunwaldt L, Galas R, Meehan TK, Melbourne WG,
Hocke K, Atmosphere sounding by GPS radio occultation: First results
from CHAMP. Geophys. Res. Lett. 28(17):3263–3266, 2001.
[6]
Wickert, J., G. Beyerle, R. König, S. Heise, L. Grunwaldt, G.
Michalak, Ch. Reigber, T. Schmidt, GPS radio occultation with CHAMP
and GRACE: A first look at a new and promising satellite configuration
for global atmospheric sounding, Annales Geophysicae, Vol. 23,
653-658, 2005.
[7] Wickert, J., G. Michalak, T. Schmidt, G.
Beyerle, C.Z. Cheng, S.B. Healy, S. Heise, C.Y. Huang, N. Jakowski, W.
Köhler, C. Mayer, D. Offiler, E. Ozawa, A.G. Pavelyev, M. Rothacher,
B. Tapley, and C. Viehweg, GPS radio occultation: Results from CHAMP,
GRACE and FORMOSAT-3/COSMIC, 20, 1, 35-50,
doi:10.3319/TAO.2007.12.26.01(F3C), 2009.
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