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 August 2020, GRUAN comprises of 30 sites, 12 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 RS92 and the Meisei RS-11G radiosonde, GRUAN Data Products (GDP) have been fully implemented and certified. Further GDPs are in certification process or under development.

Latest news

Article Data product |

AMT paper von Rohden et al. 2021 in review

"Laboratory characterisation of the radiation temperature error of radiosondes and its application to the GRUAN data processing for the Vaisala RS41"…


Station |

Paramaribo (Suriname) first GRUAN site in South America

With the establishment of a new site in Paramaribo we have reached the landmark of the first GRUAN site on the South American continent. This is…


Conference |

ICM-13: virtual meeting 15-19 November 2021

In view of the ongoing Covid-19 situation, ICM-13 will again be organized as a virtual meeting.

Article Measurement |

AMT paper Ingleby et al. 2021 in review

The following GRUAN-relevant paper was published at AMT: "On the quality of RS41 radiosonde descent data" by Ingleby et al. The paper is open for…


Event Station |

Lauder 60th

The GRUAN site Lauder (NZ) was founded 60 years ago.

Article |

AMT paper Graf et al. 2021

The following GRUAN-relevant paper was published at AMT: "Compact and lightweight mid-infrared laser spectrometer for balloon-borne water vapor…

Meeting Document |

Report of the GRUAN ICM-12 released to the public

The report of GRUAN's annual meeting, ICM-12, has been published. ICM-12 was organized as a virtual meeting 16-20 November 2020.

Article |

METZ paper Philipona et al. 2020

The following GRUAN-relevant paper was published at METZ: "Balloon-borne radiation measurements demonstrate radiative forcing by water vapor and…


Meeting |

ICM-12 Virtual: 16-20 November 2020

The 12th GRUAN annual Implementation and Coordination Meeting, ICM-12, took place 16-20 November 2020 as virtual meeting.

All presentations and…