The goal of the IGS Troposphere Working Group (WG) is to improve the accuracy and usability of GNSS-derived troposphere estimates. The members and chair produce IGS final troposphere estimates for nearly all the stations of the IGS network, and coordinate WG projects/IGS Workshop technical sessions in support of the WG goals.

More information is below. Though much has changed, a 2015 overview of activities can be found here. Please feel free to contact chair Dr. Sharyl Byram if you have questions or would like more information.

Info re Working Group

The IGS Troposphere Working Group welcomes new members! Info:

  • Comprised of 50+ members from around the globe
  • Meets at least twice per year:
    • In conjunction with the annual IGS Workshop (month varies)
    • Meetings are simulcast online so that members unable to attend in person can participate
  • Current WG projects include:
    • IGS/GOP multi-technique troposphere-estimate comparison web tool: see here
    • Standardization of tropo_sinex format:
      • Documentation of the effort plus the proposed format is here
  • Join the TWG email list here
  • Access TWG email archives (list subscribers only) here
Info re IGS tropo estimates

The IGS Final Troposphere Estimates are produced at the US Naval Observatory (Washington DC USA) using Bernese GNSS Software 5.2 in precise point positioning mode [Zumberge et al., 1997]. Estimates are provided for all IGS network receivers meeting data-quality and -availability criteria, which is typically ~360 stations/day. Details:

  • One 24-hr result file per IGS receiver per day
  • Result file contents: estimates of total troposphere zenith path delay, north, and east gradient components every 300 s
  • Availability: approximately 21 d after data collection (due to use of IGS Final products; see "Models/inputs" below)
  • Download estimates here
  • Models/inputs used:
    • Orbit/clock/ERP input: IGS FInal Estimates
    • Elevation angle cutoff: 7 degrees (receiver dependent)
    • A priori troposphere estimate: dry Neill model [Neill, 1996]
    • Relative a priori sigmas: 1 mm (ZTD), 0.1 mm (gradients)
    • This poster tells you more about current IGS troposphere estimate production.
Meetings, Future and Past

Future meetings:

  • IGS Workshop 2019: stay tuned!

Past meeting archives:


2019/02/22 EGU General Assembly 2019 (7-12 Apr 2019; Vienna, Austria) sessions/items of interest:
2018/10/31 AGU 2018 Fall Meeting sessions/items of interest:
  • PDF list (with links) of troposphere-related sessions
2018/10/26 A list of IGS 2018 Workshop troposphere-related meetings/presentations can be found here
2018/10/26 Reminder: the new tropo-sinex format under consideration can be found here
2018/08/17 Abstract-submission deadline for 2018 IGS Workshop (Wuhan, China) extended to 29 Aug 2018.
2018/08/16 Abstracts for 29 Oct - 2 Nov 2018 IGS Workshop (Wuhan, China) are due 22 Aug 2018.
Call for troposphere abstracts; workshop-wide call for abstracts.
2018/05/22 Read U of Genoa new Earth, Planets and Space contribution here or here.
2018/03/14 EGU 2018 General Assembly Program (8-13 Apr 2018)
2018/03/14 Santa Claus Flyover tracking starts 1 Dec 2018!
2017/11/22 AGU 2017 Fall Meeting GNSS Meteorolgy Poster Session (13 Dec 2017; #G13D)
2017/11/22 AGU 2017 Fall Meeting Geodesy Program (11-15 Dec 2017)
2017/11/22 AGU 2017 Fall Meeting Atmospheric Sciences Program (11-15 Dec 2017)

  • Boehm J, A Niell, P Tregoning and H Schuh, Global Mapping Function (GMF): A New Empirical Mapping Function Based on Numerical Weather Model Data, Geophys. Res. Lett., 33 (7), L07304, doi:10.1029/2005GL025546, 2006.
  • Niell A E, Global Mapping Functions for the Atmospheric Delay at Radio Wavelengths, J. Geophys. Res., 101 (B2): 3227-46, 1996.
  • Zumberge J F, M B Heflin, D C Jefferson, M M Watkins and F H Webb, Precise Point Positioning for the Efficient and Robust Analysis of GPS Data from Large Networks, J. Geophys. Res., 102 (B3): 5005-17, 1997.