Modeling the response of permafrost affected mesoscale watersheds to long term warming
Abstract
Recently observed increase in the Arctic river runoff and subannual reshaping of the hydrographs demand an explanation of processes responsible for these changes. Theoretical models of heat and water dynamics in the ground material suggest a non-linear response of permafrost to increase in air temperature.
In this work, we employ a distributed water-balance model WaSiM to investigate how a synthetic mesoscale watershed reacts to changes in the air temperature on a millennial timescale. All case studies are completed using the same precipitation forcing for Alaska. The change in temperature we apply is based on the observed trend for the same area. We analyze the sensitivity of the present-day steady state and its potential responses to different levels of warming and to soil parameters within the watershed such as the van Genuchten soil retention parameter, hydraulic conductivity and the anisotropy of soil properties. In addition, we investigate how roughness and steepness of the watershed terrain affect the permafrost and water-balance responses to the warming on the millennial timescale. Furthermore, we analyze changes in the water-balance components: evapotranspiration, river runoff and groundwater recharge as well as changes in the runoff components: surface flow, interflow, and baseflow. Preliminary results suggest that timing and severity of an increase in the baseflow and an associated decrease in the interflow strongly depend on the physical parameters of the ground material and occur on the millennial timescale, whereas the surface flow and evapotranspiration responses are triggered almost immediately.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.C51C1053D
- Keywords:
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- 0702 Permafrost;
- CRYOSPHEREDE: 0710 Periglacial processes;
- CRYOSPHEREDE: 1625 Geomorphology and weathering;
- GLOBAL CHANGEDE: 1807 Climate impacts;
- HYDROLOGY