The GRUAN Manual (GCOS-170) and the accompanying GRUAN Guide to Operations (GCOS-171) consolidate the essential framework for network operations, providing a comprehensive overview of measurement procedures and technical requirements. These documents establish mandatory operating protocols and guidelines designed to assist participating sites, the GRUAN Lead Centre, and the WG-GRUAN in achieving the network’s strategic objectives. The primary mission of GRUAN is to provide vertical profiles of reference measurements suitable for the reliable detection of global and regional climate changes. Furthermore, these observations serve as a traceable reference standard for the calibration and validation of satellite-based measurements of atmospheric Essential Climate Variables (ECVs). This document serves to update and refine the measurement practices and station requirements previously set forth in the existing Manual and Guide. It is intended to function as a unified access point to these technical specifications for all station operators and GRUAN stakeholders, ensuring consistency and streamlined implementation across the network.

• GCOS-171, The GCOS Reference Upper-Air Network (GRUAN) GUIDE. GCOS-171, Version 1.1.0.3, March 2013, WIGOS Technical Report No. 2013-03: https://library.wmo.int/viewer/49958/download?file=gcos_171.pdf&type=pdf&navigator=1
• GCOS-170, The GCOS Reference Upper-Air Network (GRUAN) MANUAL. GCOS-170, Version 1.1.0.3, March 2013, WIGOS Technical Report No. 2013-02: https://library.wmo.int/viewer/49952/download?file=gcos_170.pdf&type=pdf&navigator=1