GCOS Reference Upper-Air Network

Task Team on GNSS Precipitable Water (GNSS-PW)

A Task Team of AOPC Working Group on GRUAN (WG-GRUAN)


The GCOS/WCRP Atmospheric Observation Panel for Climate (AOPC) Working Group on GRUAN was established in 2006 in recognition of the importance of initiating reference-quality observations of atmospheric column properties, in particular temperature and water vapour, from the surface into the stratosphere to enhance the monitoring and understanding of climate variability and change. The initial GRUAN Implementation Plan (GCOS-134),  published in 2009, was superseded by a new GRUAN Implementation Plan, covering the period 2013-2017, in January 2013 (GCOS-165). At the second Implementation and Coordination Meeting held in Payerne, Switzerland, in March 2010 the Working Group, Lead Centre and initial sites agreed to the instigation of a number of task teams.

The GRUAN Global Navigation Satellite Systems (GNSS) precipitable water (GNSS-PW) Task Team (TT) was established in summer 2010 as one of then six GRUAN TTs. TTs are charged with addressing critical GRUAN requirements. Ground-based GNSS-PW was identified as a Priority 1 measurement for GRUAN, and the GNSS-PW TT’s goal is to develop, update and assist implementing explicit guidance on hardware, software and data management practices to obtain GNSS-PW measurements of consistent quality at all GRUAN sites.

Task Team roles and responsibilities

Under the auspices of the WG-GRUAN the GNSS-PW task team was established to:

Reporting and governance



GCOS-134: GRUAN Implementation Plan 2009-2013. GCOS-134, WMO Tech. Doc. 1506.

GCOS-165: GRUAN Implementation Plan 2013-2017. GCOS-165, June 2013.

GRUAN-TD-6: Wang et al.,Global Navigation Satellite System (GNSS) - Precipitable Water (PW) Omnibus, GRUAN-TD-6, v2.0 (2019-08-21).


(as at 2023-03-10)

Name Organisation
Kalev Rannat (co-chair) Tallinn University of Technology, EE
Jonathan Jones (co-chair) Met Office, UK
John Braun UCAR, USA
Galina Dick GeoForschungsZentrum Potsdam, DE
Gunnar Elgered Chalmers University, SE
Rosa Pacione E-GEOS, IT
Yoshinori Shoji Meteorological Research Institute, JP
Jens Wickert GeoForschungsZentrum Potsdam, DE
George Liu Hong Kong Polytechnic University, HK

Presentations and Reports

Terms of reference












GRUAN Documents