GCOS Reference Upper-Air Network

Task Team on Radiosondes

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


The GCOS/WCRP Atmospheric Observation Panel for Climate (AOPC) Working Group on GCOS Reference Upper Air Network (WG-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. At the second GRUAN Implementation and Coordination Meeting (ICM) 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 Task Team on Radiosondes exists to provide guidelines for GRUAN on how to obtain the best possible reference quality data from radiosoundings. According to the reference specifications (Immler et al., 2010) that have been approved during the ICM-2 meeting in Payerne, "reference quality" means that a data product:

In this context the Task Team supports efforts from manufacturers, scientists (at sites) and the GRUAN Lead Centre to take the steps that are necessary to obtain reference quality in radiosoundings, i.e. to choose suitable sensors, to define correction algorithms and QA/QC procedures, to identify and quantify sources of uncertainty, to define data formats for submission, and to provide proper documentation of this entire chain including technical documents and peer-reviewed publications.

It should be noted that a “radiosonde” has several components such as a temperature sensor, a humidity/water vapor sensor, a pressure (or GPS altitude) sensor, a balloon-parachute-unwinder part, etc. The task team will need to discuss issues related to each of these components and, if necessary, will try to bring in additional expertise by appointing ad-hoc, “associate” members.  We will also gather the information on existing sensors for the GRUAN priority 2, 3 and 4 variables (see GCOS, 2013) and recommend specific actions. An important issue to consider is the long-term stability of radiosonde observations in order to ensure that GRUAN data series are useful for monitoring climate change. While it is desirable that the best possible equipment is used at GRUAN sites at any time, it is also important to assess and limit the damage that instrumental change can cause to climate data series due to improperly corrected or undiscovered systematic offsets or biases.

The Task Team needs to make recommendations in terms of procedures, launch schedules and algorithms that meet the specifications required to achieve the goals of GRUAN in co-operation with other task teams and groups of researchers such as the GRUAN scientific coordinator and the GRUAN Analysis Team for Network Design and Operations Research (GATNDOR).


GCOS (Global Climate Observing System), The GCOS Upper-Air Reference Network (GRUAN) GUIDE, GCOS-171, WIGOS Technical Report, No. 2013-03, 2013.

F. J. Immler, J. Dykema, T. Gardiner, D. N. Whiteman, P. W. Thorne, and H. Vömel, Reference Quality Upper-Air Measurements: guidance for developing GRUAN data products Atmos. Meas. Tech., 3, 1217-1231, 2010, doi:10.5194/amt-3-1217-2010.


Under the auspices of the Working Group on Atmospheric Reference Observations the task team was established to:

Reporting and governance



(as at 2022-10-11)

Name Organisation
Masatomo Fujiwara (co-chair) Faculty of Environmental Earth Science, Hokkaido University, JP
Christoph von Rohden (co-chair) DWD, DE
Frank Schmidlin US
Hannu Jauhiainen The Assocation of Hydro-Meteorological Equipment Industry, FI
Rigel Kivi Finnish Meteorological Institute, Arctic Research Centre, FI
Masami Iwabuchi Japan Meteorological Agency, JP
Yang RongKang China Meteorological Administration, CN
Sergey Kurnosenko Scientific Software Consultant, US
Bruce Ingleby ECMWF, UK
David Edwards Met Office, UK
Gonzague Romanens MeteoSwiss, CH
Frédéric Vogt MeteoSwiss, CH
Jean-Charles Dupont Institut Pierre Simon Laplace, FR

Presentations and Reports

Terms of reference