Changing Arctic River Dynamics Cause Localized Permafrost Thaw

Abstract

Permafrost in the Arctic regions is degrading in response to decades of amplified warming.Advanced degradation of ice-rich permafrost could significantly alter the water balance by increasing runoff and flooding. How do the hydrological changes in river systems, in turn, affect the permafrost thermal state, specifically in floodplains? First, we develop a first-order heat budget approach to simulate evolving river-water temperature. The river-water thermal model includes heat exchanges at both the air-water and water-subsurface interfaces and can accurately estimate water temperature. Then, river-water temperature is employed as an upper boundary condition for the control volume permafrost model, which models the thermal state of shallow permafrost. The combined model is validated and applied in the Kuparuk River floodplain, Alaska. Results indicate that permafrost warms rapidly during inundation and that channelbelt active layer thickness can deepen by more than 1 m. We find that earlier arrival of the spring freshet and associated earlier inundation onset, as well as increase in river discharge, can significantly increase subsurface permafrost temperature and lead to a deepening of the active layer. In recent years Kuparuk River streamflow has arrived earlier, and mean annual river discharge has increased by 35% since the 1970s. New permanent water and seasonal water appeared throughout the river network of the Kuparuk River since the 1980s according to satellite observations. These hydrological changes likely have contributed to the expansion of riverbed thaw bulbs and the degradation of floodplain permafrost.

The Pace of Fluvial Meanders on Mars and Implications for the Western Delta Deposits of Jezero Crater

“…One major unknown, however, lies in the possibility that riverbanks were frozen (e.g., Bishop et al, 2018;Cassanelli & Head, 2019), as the presence of ground ice in riverbanks, channel hydraulic geometry, and lateral migration rate are interlinked through complex feedbacks (e.g., Zheng et al, 2019). However, the nature of this relationship is not known on Mars, and it likely would have been a strong function of temperature.…”

Mobilization of Geochemical Elements to Surface Water in the Active Layer of Permafrost in the Russian Arctic

“…Ice wedge degradation has also been proven to be related to the water balance of lowlands across Arctic landscapes, and to increased streamflow (Liljedahl et al., 2016). Several studies have observed substantial increases in discharges from the major Eurasian Arctic rivers due to the warming climate (Browny et al., 2019; Feng et al., 2019; Lammers et al., 2001; Yang et al., 2002; Zheng et al., 2019). Raudina et al.…”

“…Ice wedge degradation has also been proven to be related to the water balance of lowlands across Arctic landscapes, and to increased streamflow (Liljedahl et al, 2016). Several studies have observed substantial increases in discharges from the major Eurasian Arctic rivers due to the warming climate (Browny et al, 2019;Feng et al, 2019;Lammers et al, 2001;Yang et al, 2002;Zheng et al, 2019). Raudina et al (2018) observed a northward shift of the permafrost boundary under climate change scenarios, and that the concentrations of dissolved organic carbon (DOC), major and trace elements, and greenhouse gases are expected to decrease in the suprapermafrost waters at the border between the thawed and frozen parts from peat soils in the western Siberia lowland.…”

Taliks, cryopegs, and permafrost dynamics related to channel migration, Colville River Delta, Alaska

“…Thorough field assessments that include drilling, soil sampling, laboratory testing, and measuring ground temperatures and groundwater levels at depths greater than tens of meters are typically challenging and expensive. More accessible methods to estimate talik occurrence, configuration, properties and/or temporal changes include measuring bottom water temperatures in lakes and channels for subsequent analytical calculations, numerical modeling, and geophysical surveying . These methods typically do not provide much information on cryopegs, although the use of ground‐penetrating radar combined with direct current resistivity surveys may help to differentiate brine from freshwater…”