Global Terrestrial Network for Glaciers (GTN-G)

Climate Change - Human Settlements - Land Resources - Sustainable Development - Global Sea Level Rise - Water Resources - Natural Hazards

Snow Cover, Glaciers and Ice Caps, Ice Sheets, (Sea Level)

On global scale; regularly updated information on glacier distribution and changes; fluctuations database at WGMS with > 3,500 glaciers since 19th century; inventory database at NSIDC with > 100,000 glaciers from mid 20th and early 21st centuries

Global Terrestrial Network for Hydrology (GTN-H)

Agriculture - Biodiversity - Climate Change - Desertification - Forests - Health - Human Settlements - Land Resources - Sustainable Development - Water and Sanitation

Precipitation, Water Vapour, River Discharge, Ground Water, Water Use, Lakes, Glaciers and Ice Caps, Soil Moisture

On global and regional scale (national monitoring programmes, science programmes); data from 1900 onwards (single variables, discontinuous)

Global Terrestrial Network for Lakes (GTN-L)

Biodiversity - Climate Change - Human Settlements - Land Resources - Sustainable Development

Lakes (Lake Level, Lake Area, Water Temperature, Ice Thickness)

Mainly on regional basis (> 600 water level reference stations); monthly and annual data input

Global Terrestrial Network for Permafrost (GTN-P)

Biodiversity - Climate Change - Human Settlements - Land Resources - Sustainable Development

Permafrost, (Ice Sheets, Snow Cover)

Mainly on regional and national basis (80-site network under IPA's Circumpolar Active Layer Monitoring (CALM); inventory and metadata for > 200 boreholes of varying depths)

Global Terrestrial Network for Rivers (GTN-R)

Agriculture - Climate Change - Desertification - Health - Human Settlements - Land Resources - Sustainable Development - Water and Sanitation

River Discharge, (Water Use, Lakes, Soil Moisture)

Mainly on regional basis (> 450 river discharge reference stations); daily data input; highly dependent on data provided by National Hydrological Services (NHS)