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Troposphere Working Group Charter and Members




GNSS can make important contributions to meteorology, climatology and other environmental disciplines through its ability to estimate troposphere parameters. Along with the continued contributions made by the collection and analysis of ground-based receiver measurements, the past decade has also seen new contributions made by space-based GNSS receivers, e.g., those on the COSMIC/FORMOSAT mission [1]. The IGS therefore continues to sanction the existence of a Troposphere Working Group (TWG).


Working Group Goals

The primary goals of the IGS TWG are to:

  • Assess/improve the accuracy/precision of IGS GNSS-based troposphere estimates.
  • Improve the usability of IGS troposphere estimates.
  • Confer with outside agencies interested in the use of IGS products.
  • Assess which new estimates should be added as “official” IGS products, and which, if any, official troposphere product sets should be discontinued.
  • Provide and maintain expertise in troposphere-estimate techniques, issues and applications.


Science Background

The primary troposphere products generated from ground-based GNSS data are estimates of total zenith path delay and north/east troposphere gradient. Ancillary measurements of surface pressure and temperature allow the extraction of precipitable water vapor from the total zenith path delay.

Water vapor, a key element in the hydrological cycle, is an important atmosphere greenhouse gas. Monitoring long-term changes in its content and distribution is essential for studying climate change. The inhomogeneous and highly variable distribution of the atmospheric water vapor also makes it a key input to weather forecasting.

Water vapor distribution is incompletely observed by conventional systems such as radiosondes and remote sensing. However, ground- and space-based GNSS techniques provide complementary coverage of this quantity. Ground-based GNSS observations produce continuous estimates of vertically integrated water vapor content with high temporal resolution over a global distribution of land-based locations; coverage is limited over the oceans (where there is no land). Conversely, water vapor can be estimated from space-borne GNSS receivers using ray tracing techniques, in which case solutions with high vertical resolution (laterally integrated over few hundred kilometers) and good oceanic/land coverage are obtained; these solutions however are discontinuous in geographic location and time.

Be it resolved that the IGS troposphere WG will:

  • Support those IGS analysis centers providing official IGS troposphere products.
  • Increase awareness/usage of IGS troposphere products by members of the atmospheric,meteorology and climate-change communities. Solicit the input and involvement of such agencies.
  • Create new IGS troposphere products as needed (as determined by consultation with the potential user community).
  • Determine the uncertainty of IGS troposphere estimates through comparison of solutions with those obtained from independent techniques, or through other means as appropriate.
  • Promote synergy between space-based and ground-based GNSS techniques through interaction with researchers in both fields.



[1] Schreiner, W., C. Rocken, S. Sokolovskiy, S. Syndergaard and D. Hunt, Estimates of the precision of GPS radio occultations from the COSMIC/FORMOSAT-3 mission, GRL 34, L04808, doi:10.1029/2006GL027557, 2007.

[2] Teke, K., J. Böhm, T. Nilsson, H. Schuh, P. Steigenberger, R. Dach, R. Heinkelmann, P. Willis, R. Haas, S. García-Espada, T. Hobiger, R. Ichikawa and S. Shimizu, Multi-technique comparison of troposphere zenith delays and gradients during CONT08, J Geod 85:395–413, DOI 10.1007/s00190-010- 0434-y, 2011.



NB: I have included the names of new subscribers to the IGS TWG email list, without necessarily confirming that they wish to be a part of the WG.
Last Name First Name Institution Country email
Ahmed Furqan Universite du Luxembourg Luxembourg
Amirkhani Mohammad Islamic Azad Univ. Tehran Iran
Bar-Sever Yoaz JPL USA
Bevis Mike OSU USA
Bock Olivier IGN-LAREG France
Boehm Johannes TU Wien Austria
Bosser Pierre ENSG/DPTS France
Bosy Jaroslaw Institute of Geodesy and Geoinformatics; Wroclaw University of Environmental and Life Sciences Poland
Braun John UCAR USA
Byram Sharyl USNO USA
Byun Sung JPL USA
Calori Andrea Univ. Roma "La Sapienza" Italy
Cao Wei Trimble Terrasat Germany
Chen Junping Shanghai Astronomical Observatory China
Colosimo Gabriele Univ. Roma "La Sapienza" Italy
Crespi Mattia Univ. Roma "La Sapienza" Italy
Deng Zhiguo GFZ Germany
Dick Galina GFZ Germany
Dousa Jan GOP Poland
Drummond Paul Trimble USA
Ghoddousi-Fard Reza Natural Resources Canada Canada
Guerova Guergana Univ. Sofia Bulgaria
Gustavson Terry ? USA?
Gutman Seth NOAA USA
Hackman Christine USNO USA
Heinkelmann Robert GFZ Germany
Herring Tom MIT USA
Hilla Steve NGS/NOAA USA
Hobiger Thomas Onsala Space Observatory; Chalmers Univ. of Technology Sweden
Januth Timon Univ. of Applied Sciences, Western Switzerland (?) Switzerland
Jones Jonathan Met Office UK UK
Langley Richard Univ. New Brunswick Canada
Leandro Rodrigo Hemisphere GNSS USA
Leighton Jon 3vGeomatics Canada/UK
Liu George Hong Kong Polytechnic University Hong Kong
Melachroinos Stavros Geoscience Australia (?) Australia
Moeller Gregor TU Wien Austria
Moore Angelyn JPL USA
Negusini Monia Inst. Radioastronomy (IRA); National Inst. Astrophysics (INAF) Italy
Nikolaidou Thaleia Univ. New Brunswick Canada
Nordman Maaria Finnish Geodetic Inst. Finland
Pacione Rosa ASI/CGS Italy
Palamartchouk Kirill Univ. Newcastle UK
Penna Nigel Univ. Newcastle UK
Perosanz Felix CNES France
Pottiaux Eric Royal Obs Belgium Belgium
Prikryl Paul Communications Research Centre, Canada Canada
Realini Eugenio GReD - Geomatics Research & Development s.r.l. Italy
Rocken Chris GPS Solutions USA
Roggenbuck Ole BKG Germany
Rohm Witold Univ. Wroclaw Poland
Romero Nacho Canary Advanced Solutions Spain
Santos Marcelo  Univ. New Brunswick Canada
Schaer Stefan AIUB Switzerland
Schoen Steffen Inst. Erdmessung, Leibniz Uni Hannover Germany
Selle Christina JPL USA
Sguerso Domenico Lab. Geodesy, Geomatics, GIS; Univ. Genoa Italy
Soudarin Laurent Collecte Localisation Satellites France
Teferle Norman Universite du Luxembourg Luxembourg
Tracey Jeffrey USNO USA
van der Marel Hans TU Delft Netherlands
Waithaka Edward Hunja Jomo Kenyatta U. of Agriculture and Technology Kenya
Wang Junhong UCAR/NCAR USA
Willis Pascal Inst. de Physique du Globe de Paris France
Xu Zong-qiu Liaoning TU China
Zhang Shoujian Wuhan Univ. China

[Last updated December 2011]