GCOS Reference Upper-Air Network

The climate reference network

The Global Climate Observing System (GCOS) Reference Upper-Air Network (GRUAN) is an international reference observing network of sites measuring essential climate variables above Earth's surface, designed to fill an important gap in the current global observing system. GRUAN measurements are providing long-term, high-quality climate data records from the surface, through the troposphere, and into the stratosphere. These are being used to determine trends, constrain and calibrate data from more spatially‐comprehensive observing systems (including satellites and current radiosonde networks), and provide appropriate data for studying atmospheric processes. GRUAN is envisaged as a global network of eventually 30-40 sites that, to the extent possible, builds on existing observational networks and capabilities.

GRUAN promotional video

This video provides an excellent overview of the goals and principles of GRUAN and its relation to the current challenges in climate research. You can find this and other public outreach material here.

Status of GRUAN sites

GRUAN is envisaged as a global network of eventually 30-40 measurement sites. To the extent possible, it builds on existing observational networks and capabilities. As at November 2022, GRUAN comprises of 31 sites, 14 of which have been GRUAN certified.

Status of data flow

A comprehensive volume of measurement data has been collected by GRUAN since 2008. The archive includes raw data and related meta-data. For the Vaisala RS41 & RS92 and the Meisei iMS-100 & RS-11G radiosondes, GRUAN Data Products (GDP) have been fully implemented and certified. Further GDPs are in certification process or under development.

Latest news

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Data product

GRUAN certification for RS41 GRUAN Data Product Version 1 (RS41-GDP.1)

The RS41 GRUAN Data Product Version 1 (RS41-GDP.1) has been certified by GRUAN.
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Data product

GRUAN certification for iMS-100 GRUAN Data Product Version 2 (IMS-100-GDP.2)

The iMS-100 GRUAN Data Product Version 2 (IMS-100-GDP.2) has been certified by GRUAN.
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Meeting

ICM-14: Presentations and documents available

The 14th GRUAN annual Implementation and Coordination Meeting, ICM-14, took place 28 November to 2 December 2022 as hybrid meeting at La Réunion. All…
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Campaign

UAII2022 field campaign

The field campaign of UAII2022 was successfully executed between 8 August and 13 September. In this period, more than 80 balloons were launched,…
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Station

GRUAN certification for Ross Island (ROS)

The GRUAN radiosounding and GNSS measurement program at Ross Island has been certified by GRUAN.
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Station

GRUAN certification for Barrow (BAR)

The GRUAN radiosounding program at Barrow has been certified by GRUAN.

Article

AMT paper Nielsen et al. 2022 published

The manuscript "Estimation of refractivity uncertainties and vertical error correlations in collocated radio occultations, radiosondes, and model…

Article

AMT paper Calbet et al. 2022 published

The manuscript "Horizontal small-scale variability of water vapor in the atmosphere: implications for intercomparison of data from different measuring…

Article

ACP paper Dekhtyareva et al. 2022 published

The manuscript "Springtime nitrogen oxides and tropospheric ozone in Svalbard: results from the measurement station network" by Dekhtyareva et al. has…

Document Data product

GRUAN Technical Note 13 published

GRUAN Technical Note 13 (GRUAN-TN-13) published with title "User Guide for the RS41 GRUAN Data Product Version 1 (RS41-GDP.1)"

Document File archive

GRUAN Technical Note 12 published

GRUAN Technical Note 12 (GRUAN-TN-12) published with title "Brief Description of Vaisala DigiCORA® 3 DataBase File Format (DC3DB)"