Impact of thawing permafrost and frozen soils on Arctic freshwater runoff under changing climate
Abstract
Hydrological models are important tools to analyse the cold regions processes, such as permafrost, seasonally frozen soil and snow cover, which are widely distributed across Canada. In Arctic regions, frozen soil processes and permafrost play a key role in runoff generation by restricting the infiltration during the frozen state, and thawing during the melting phase. Therefore, the representation of such processes in models is critical for model projections under climate change, and hence for reducing the uncertainty associated with freshwater runoff. In this research, the frozen soil infiltration was incorporated in HYPE model, and the output variables such as soil temperature and soil moisture were validated with field observations across Nelson Churchill River Basin (NCRB). The improved HYPE-NCRB model was used to project climate change impacts on soil moisture, soil temperature, and implications on model uncertainty associated with the projection of streamflow. A suite of 14 GCMs and 2 RCP (RCP 4.5 and RCP 8.5) scenarios representing 87% of the variability of 154 climate scenarios were bias corrected at the catchment scale for a baseline period of 1981-2010 and future period of 2020-2070. Average soil temperature across the basin is projected to increase by up to 2.6℃, with only moderately increasing soil moisture (less than 3%). Projected increases in temperature, however, have profound effects on frozen soil, permafrost cover and Arctic freshwater runoff. Our study shows degradation in permafrost cover from 75,000 sq. km to less than 10,000 sq.km. by the 2060s, and projected increases in runoff up to 40% within parts of the basin. The study could be beneficial to further access the impact of climate change and degrading permafrost on infrastructures and ecosystems of the Arctic .
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.C23D1588B
- Keywords:
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- 3349 Polar meteorology;
- ATMOSPHERIC PROCESSES;
- 0456 Life in extreme environments;
- BIOGEOSCIENCES;
- 0750 Sea ice;
- CRYOSPHERE;
- 1620 Climate dynamics;
- GLOBAL CHANGE;
- 1621 Cryospheric change;
- GLOBAL CHANGE;
- 1622 Earth system modeling;
- GLOBAL CHANGE;
- 1694 Instruments and techniques;
- GLOBAL CHANGE;
- 4207 Arctic and Antarctic oceanography;
- OCEANOGRAPHY: GENERAL