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.

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 May 2019, GRUAN comprises of 26 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.