Long‐term changes in the ground thermal regime of an artificially drained thaw‐lake basin in the Russian European north

Abstract

Long‐term (1982–1995) observations of the ground thermal regime of a drained thaw‐lake basin in the Pechora Lowlands of the Russian European north revealed a high spatial and temporal variability in the ground temperature response to artificial drainage. The thermal response was controlled by the atmospheric climate and by evolution of the landsurface following drainage. Observed changes in permafrost conditions were related to three climatic subperiods identified from air and ground temperature trends. The first (1982–1984) was characterized by gradual ground cooling associated with partial formation of permafrost patches under the initial stage of formation of marshy meadows. The second (1985–1987) involved strong ground cooling, resulting in the formation of a subsurface permafrost layer beneath most of the basin. The third (1988–1995) was marked by a gradual increase in annual mean ground temperature, promoting partial permafrost degradation under marshy meadows and willow stands. Initially, newly aggraded permafrost remained under peat mounds and tundra meadows. The spatial pattern of permafrost change can be attributed to heterogeneous landsurface evolution and variable snow thickness. Four distinct ground temperature regimes are distinguished: (i) thawed ground, (ii) deep permafrost, (iii) unstable permafrost and (iv) stable permafrost.

Geophysical Observations of Taliks Below Drained Lake Basins on the Arctic Coastal Plain of Alaska

“…Processes occurring in the basin following lake drainage include permafrost aggradation, basin floor frost heave (Liu et al., 2014), ice‐wedge and segregated ground ice formation (Jorgenson & Shur, 2007; Mackay, 1981, 1997, 1999; Roy‐Léveillée & Burn, 2016), vegetation succession, and peat accumulation (Bockheim et al., 2004; Hinkel et al., 2003). Postdrainage processes have implications for permafrost dynamics (Kaverin et al., 2018; Mackay, 1997; Mackay & Burn, 2002a, 2002b), the global carbon cycle (Fuchs et al., 2019; van Huissteden et al., 2011), hydrology (Arp et al., 2019), vegetation productivity (Koch et al., 2018; Lara et al., 2018; Zona et al., 2010), and hazards assessment (Arp et al., 2020).…”

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

“…Some direct observations on the geometry and properties of taliks and cryopegs are available in the literature, with most of them focused at shallow depths and/or obtained from limited data, implying that conclusions may have been partially based on assumptions rather than mainly on field measurements. 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.…”

Lake Drainage in Permafrost Regions Produces Variable Plant Communities of High Biomass and Productivity

“…The drainage of thermokarst lakes triggers a post-drainage succession. The initial post-drainage phase is characterized by gradual ground cooling associated with formation of permafrost [ 51 ] and the growth of segregated near-surface ground ice [ 52 ]. Permafrost aggradation occurs differently in different parts of the basin.…”

“…These processes create micro-mosaic of wetter and drier areas in basins [ 52 , 55 , 56 ]. After several decades, newly formed permafrost is present under frost mounds with peat sediment, but it is absent under wet marshy meadows [ 51 ]. The variation of plant communities within the basin will influence the values of NDVI observed from satellites.…”