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GCOS Terrestrial ECV T7
Permafrost & Seasonally Frozen Ground
Introduction: Frozen ground (as measured by permafrost temperatures and depth of seasonal freezing/thawing) reacts sensitively to climate and environmental change in high latitude and mountain regions. Corresponding changes result in the thermal mode of permafrost and subsurface conditions and have important impacts on terrain stability, coastal erosion, surface and subsurface water, the carbon cycle, and vegetation development. Combined monitoring of meteorological and hydrological variables, soil and vegetation parameters, carbon dioxide and methane fluxes, and the thermal mode of the active layer and permafrost on upgraded “reference sites” is the recommended observing approach. Standardised in situ measurements are essential, both to calibrate and to verify regional and global climate models.
The Global Terrestrial Network for Permafrost (GTN-P), coordinated by the International Permafrost Association (IPA), forms a GCOS/GTOS baseline network for these variables. The Geological Survey of Canada (Ottawa) maintains borehole metadata files and coordinates thermal data management and dissemination. Every five years, the NSIDC prepares and distributes a Circumpolar Active Layer Permafrost System CD containing information and data acquired in the previous 5 years. The establishment of permafrost national centres to collect and analyse data is recommended.
GTN-P currently involves 16 participating countries, with hundreds of active sites in the Circumpolar Active Layer Monitoring (CALM) network and identified boreholes for monitoring permafrost thermal states, Some of these need to reactivate their measurement campaigns, and soil vertical displacement measurements and permafrost temperatures measurements should become a part of active layer monitoring. GTN-P has also identified new borehole and active layer sites needed to obtain representative coverage in the Europe/Nordic region, within the Russian Federation and within Central Asia (Mongolia, Kazakhstan, and China); in the Southern Hemisphere (South America, Antarctica); and in North American mountain ranges and lowlands. A few reference sites have been recommended for development, and this would establish a baseline network of Thermal State of Permafrost sites within the International Network of Permafrost Observatories (INPO).
Presently, GTN-P in situ data acquisition operates on a largely voluntary basis through individual national and regionally-sponsored programmes. Regional projects support local networks and observatories, such as the US Geological Survey Alaskan deep borehole network and the US National Science Foundation-supported CALM sites, the Russian Academy of Sciences “Evolution of Cryosphere” Program, Canadian transects, Permafrost and Climate in Europe activities, and GEF in Mongolia, among others. Measurement and reporting standards are emerging, but further work is needed to prepare and publish definitive reporting standards. Upscaling techniques for research sites and permafrost networks, initially on upgraded reference sites, are required to complement active layer and thermal observing networks with monitoring of active geological processes (e.g., slope processes, thermokarst and lake development, coastal dynamics, and surface terrain stability).
Declining permafrost areas and seasonally-frozen ground form a dynamic whole. Observing the extent of seasonally-frozen ground is an important activity in monitoring permafrost decline.
(Source: WMO/IOC Implementation Plan for the Global Observing System for Climate in Support of the UNFCCC (2010 Update) GCOS-138/GOOS-184/GTOS-76/WMO-TD/No. 1523)
References:
Data, Product, Metadata and Information Access
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