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Circumpolar assessment of spatial and temporal variability of permafrost temperature and active layer thickness based on data from the Global Terrestrial Network for Permafrost (GTN-P)тезисы доклада
- Авторы: Streletskiy D., Biskaborn B., Romanovsky V., Smith S., Shiklomanov N., Nötzli J., Vieira G., Schoeneich P., Maslakov
- Сборник: International Conference «Earth's Cryosphere: Past, Present and Future» (June 4-8, 2017, Pushchino, Russia). Program and conference materials
- Тезисы
- Год издания: 2017
- Первая страница: 19
- Последняя страница: 21
- Аннотация: Permafrost is defined as soil, rock, and any other subsurface earth material that exists at or below 0°C continuously for two or more consecutive years. On top of permafrost is the active layer, which thaws during the summer and freezes again the following winter. The mean annual temperature of permafrost and the active layer thickness (ALT) are good indicators of changing climate and therefore designated as essential climate variables by the Global Climate Observing System Program of the World Meteorological Organization. Permafrost temperature and ALT are also essential variables in designing, building and maintaining infrastructure in the Arctic Regions, particularly in the context of Russia. Unlike majority of the Arctic, Russian permafrost regions have presence of substantial population and developed infrastructure. In such cases permafrost changes due to climate are exacerbated in areas of human activities and infrastructure development and may have severe socio-economic consequences as negative impacts of permafrost warming are expected to continue resulting in further deterioration of the infrastructure if adequate measures are not taken into account. That is why a reliable source of high quality data on permafrost temperature and ALT under changing climatic conditions is critically important for the sustainable development of the Arctic Regions in general, and in Russia in particular. The Global Terrestrial Network for Permafrost (GTN-P) provides systematic long-term measurements of permafrost temperature and active layer thickness (ALT), and is part of the Global Terrestrial Observing System of the Global Climate Observing System. Long-term monitoring of permafrost thermal state and active layer thickness generates essential baseline information for the assessment of climate change impacts in polar and high mountain regions and is particularly important in the context of Russia. The GTN-P data management system (DMS, gtnpdatabase.org) allows automatic data submission, standardization, quality control, processing, and data access and provides opportunity to evaluate spatial and temporal variability of permafrost temperature and ALT at various cold regions. Presently 1350 TSP boreholes and 250 active layer sites are registered in the DMS. While the majority of European and North American sites now feature multi-year borehole data, ground temperature data for the majority of the Russian sites are not available warranting further data integration from this region. Using DMS capabilities we selected sites with data available around the last International Polar Year and in the last five years (2010-2015) and estimated changes in thermal state of permafrost and active layer thickness between the two reference periods. Permafrost temperature has generally increased across the entire permafrost domain, which is consistent with air temperature trends. The greatest increases in permafrost temperature are found in the High Arctic of Canada and western Siberia and are generally pronounced in regions with cold continuous permafrost such as Russia and North America. In the Subarctic, where permafrost temperatures are relatively high and within 2°C of the freezing point, there has been little change and permafrost temperature is similar to that of the IPY snapshot. In Alpine permafrost areas most measurement sites also show significant warming since 2009. In Antarctica, permafrost temperature showed various trends, depending on regional changes in atmospheric temperature and snow accumulation. ALT exhibits large interannual variability, but has generally increased in the majority of regions, especially in European Arctic where several sites experienced permafrost degradation to the degree that does not allow to use mechanical probing to continue monitoring. In several locations thaw penetration into the ice-rich layer rather than ALT thickening was observed under warming climatic conditions. This underscores the importance of thaw subsidence in understanding the response of permafrost system to climate change. The results reveal further need for improved geographic coverage of the observational network, further refining of monitoring standards and integration of other ecosystem and climatic variables in order to better assess changes in permafrost system at global scales.
- Добавил в систему: Маслаков Алексей Алексеевич