GCOS Reference Upper-Air Network

AOPC Working Group on GRUAN



The GCOS/WCRP Atmospheric Observation Panel for Climate (AOPC ) Working Group on GRUAN (WG-GRUAN), formerly named Working Group on Atmospheric Reference Observations (WG-ARO), was established in 2006 in recognition of the importance of initiating reference-quality observations of vertical profiles of essential climate variables from the surface into the stratosphere to enhance monitoring and understanding of climate variability and change.

The 2004 GCOS Implementation Plan identified the establishment of a reference-quality network as “a very high priority”. The 2010 Update of the GCOS Implementation Plan (GCOS-138) reiterated the call for the establishment of the GCOS Reference Upper-Air Network (GRUAN) for reference upper-air measurements and a complementary system for reference measurements from satellites, and support of reanalysis and reprocessing activities as a key need. Since 2008, the German Meteorological Service, Deutscher Wetterdienst (DWD), have been hosting the GRUAN Lead Centre, consisting of scientific and secretarial support at their Lindenberg Observatory to oversee day-to-day operations of the network. Involvement of WMO in GRUAN operations occurs through representatives from relevant WMO Technical Commissions as ex-officio members on the WG-GRUAN. The initial GRUAN Implementation Plan (GCOS-134), published in 2009, is superseded by the new GRUAN Implementation Plan, covering the period 2013-2017, published in January 2013 (GCOS-165).

It is the Working Group’s responsibility to facilitate this implementation, liaising with other groups and national and international bodies to ensure that an eventual GRUAN is fit for purpose, robust and has the required long-term commitment and management structures. The WG-GRUAN also provides guidance to the GRUAN Lead Centre. The WG-GRUAN membership consists of a broad range of scientific and technical experts who contribute expert oversight and support to GRUAN development and operations.

The AOPC, supported by the GCOS Secretariat, and guided by the GCOS Steering Committee, provides direction and oversight of GRUAN. The WG-GRUAN provides direct guidance on the operation of GRUAN and is supported by specific GRUAN Task Teams. A GRUAN Scientific Coordinator guides the initiation and undertaking of specific research projects in support of GRUAN operations. The day-to-day management and coordination of the network, including training and ensuring the archival and dissemination of GRUAN data, is the responsibility of the GRUAN Lead Centre.

Working group roles and responsibilities

The working group has a range of roles and responsibilities that reflect the GCOS and WMO expectations of its outputs. Here, these have been arranged under broad categories that reflect the core facets of the expected work.


Site selection, assessment, and certification


Advocacy and outreach

Mode of operation


as at October 2023

Members *

Fabio Madonna (co-chair) CNR - IMAA, IT ()
Masatomo Fujiwara (co-chair) Hokkaido University, JP ()
Arnoud Apituley KNMI, NL
Alessandro Fasso University of Bergamo, IT
Tom Gardiner National Physical Laboratory, UK
Thierry Leblanc NASA/JPL, US
Kalev Rannat Tallinn University of Technology, EE
Bomin Sun NOAA, US
Krunoslav Premec WMO, CH
Imke Durre NOAA, US
Howard Diamond NOAA, US
Erik Anderson ECMWF, UK
Richard Querel NIWA, Lauder, NZ
Caterina Tassone WMO, CH
Lori Borg University of Wisconsin, Madison, US
Tim Oakley WMO, CH
Evan Keeler ARM, US
Graziano Coppa INRIM, IT
Jonathan Jones MetOffice, UK
Axel von Engeln EUMETSAT, DE
Marion Maturilli AWI, DE
Nico Cimini University of L'Aquila, IT
Christoph von Rohden DWD, DE
Ryan Stauffer NASA, US

GRUAN Lead Centre representative

GRUAN Lead Centre representative
Ruud Dirksen DWD, Germany ()

* ‘Members’ serve in their personal capacity as experts, whereas ‘ex-officios’ serve in their respective role, representing organizations or programmes.