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 the end of 2016, GRUAN comprises of 22 sites, 9 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 radiosonde, the first GRUAN Data Product (GDP) has been fully implemented and available since 2012. Further GDPs are under development.

Structure of website

Network

Information about organisation and parts of network

Data

Information about data, data handling and data products

Instruments

Information about instruments used at GRUAN stations

Documentation

Archive of and information about GRUAN-related documents

Community

Collection of all community tools

About GRUAN

Why do we need GRUAN?