wgms is a service of the International Association of the Cryospheric Sciences of the International Union of Geodesy and Geophysics (IACS, IUGG) as well as of the World Data System of the International Council for Science (WDS, ICSU) and works under the auspices of the United Nations Environment Programme (UN Environment), the United Nations Educational, Scientific and Cultural Organization (UNESCO), and the World Meteorological Organization (WMO).
The wgms maintains a network of local investigators and national correspondents in all countries involved in glacier monitoring. As a contribution to the Global Climate Observing System (GCOS), the Division of Early Warning and Assessment and the Global Environment Outlook (GEO) of UN Environment, and the International Hydrological Programme of UNESCO, the wgms collects and publishes worldwide standardized glacier data.
In close collaboration with the U.S. National Snow and Ice Data Center (NSIDC) and the Global Land Ice Measurements from Space (GLIMS) initiative, the wgms is in charge of the Global Terrestrial Network for Glaciers (GTN-G) within GCOS. GTN-G aims at combining (a) in-situ observations with remotely sensed data, (b) process understanding with global coverage and (c) traditional measurements with new technologies by using an integrated and multi-level strategy.
The tasks of GTN-G are:
- to collect and publish standardized data on glacier fluctuations at 5-yearly intervals,
- to prepare a bulletin reporting mass balance results of selected reference glaciers and ice caps at 2-yearly intervals,
- to manage and upgrade the existing inventory of glaciers and ice caps,
- to stimulate satellite observations of remote glaciers and ice caps in order to reach global coverage, and
- to periodically assess ongoing changes.
Amongst the three bodies of GTN-G, key expertise for in-situ measurements and glacier fluctuations has traditionally been located at WGMS, whereas GLIMS and NSIDC have mainly focused on remote sensing and data management. Today, the WGMS compiles in annual calls standardized data on glacier changes in length, area, volume and mass (task 1 and 5) and publishes the results in the Global Glacier Change Bulletin at 2-yearly intervals (task 2). NSIDC hosts and updates the glacier inventory databases (task 3). The GTN-G officers lead and participate in working groups and initiatives to stimulate remote sensing of glaciers (task 4) and periodically assess ongoing changes (task 5).
A concise overview on GTN-G, its operational bodies, and the monitoring strategy is found here.