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Journal of Geodesy

, Volume 81, Issue 6–8, pp 503–514 | Cite as

Comparisons of homogeneously reprocessed GPS and VLBI long time-series of troposphere zenith delays and gradients

  • Peter SteigenbergerEmail author
  • Volker Tesmer
  • Manuela Krügel
  • Daniela Thaller
  • Ralf Schmid
  • Sibylle Vey
  • Markus Rothacher
Original Article

Abstract

Troposphere parameters estimated from space-geodetic techniques, like the Global Positioning System (GPS) or Very Long Baseline Interferometry (VLBI), can be used to monitor the atmospheric water vapor content. Although the troposphere can only be monitored at discrete locations, the distribution of the instruments, at least the GPS antennas, can be assumed to be quasi-global. Critical in the data analysis are systematic effects within each single technique that significantly degrade the accuracy and especially the long-term stability of the zenith delay determination. In this paper, consistent time-series of troposphere zenith delays and gradients from homogeneously reprocessed GPS and VLBI solutions are compared for a time period of 11 years. The homogeneity of these completely reprocessed time-series is essential to avoid misinterpretations due to individual model changes. Co-located sites are used to investigate systematic effects and the long-term behavior of the two space-geodetic techniques. Both techniques show common signals in the troposphere parameters at a very high level of precision. The biases between the troposphere zenith delays are at the level of a few millimeters. On the other hand, long-term trends significantly differ for the two techniques, preventing climatological interpretations at present. Tests assume these differences to be due to mathematical artifacts such as different sampling rates and unmodeled semi-annual signals with varying amplitudes.

Keywords

Troposphere zenith delay Troposphere gradients Global Positioning System Very Long Baseline Interferometry 

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Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Peter Steigenberger
    • 1
    • 2
    Email author
  • Volker Tesmer
    • 3
  • Manuela Krügel
    • 3
  • Daniela Thaller
    • 1
    • 2
  • Ralf Schmid
    • 4
  • Sibylle Vey
    • 5
  • Markus Rothacher
    • 6
  1. 1.Forschungseinrichtung SatellitengeodäsieTechnische Universität MünchenMünchenGermany
  2. 2.Department of Geodesy and Remote SensingGeoForschungsZentrum PotsdamPotsdamGermany
  3. 3.Deutsches Geodätisches ForschungsinstitutMünchenGermany
  4. 4.Institut für Astronomische und Physikalische GeodäsieTechnische Universität MünchenMünchenGermany
  5. 5.Institut für Planetare GeodäsieTechnische Universität DresdenDresdenGermany
  6. 6.Department of Geodesy and Remote SensingGeoForschungsZentrum PotsdamPotsdamGermany

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