Changes in lake area in response to thermokarst processes and climate in Old Crow Flats, Yukon

Abstract

Growing evidence indicates that lake-dominated ecosystems at high latitudes are undergoing significant hydrological changes. Research examining these changes is complicated because both thermokarst and climatic processes likely influence lake dynamics. To examine the relative impacts of these processes in permafrost landscapes, we investigated the dynamics of lake area and number in Old Crow Flats (OCF), Yukon using historical air photos and satellite imagery. Between 1951 and 2007, OCF experienced a decline of~6000 ha in total lake area but gained 232 lakes. Close to half (49%) of the difference in lake area was driven by the rapid and persistent drainage of 38 large lakes. These catastrophic drainages were associated with new or enlarged outlet channels, resulted in the formation of numerous residual ponds, and were likely driven by thermokarst processes. Our analysis shows that catastrophic lake drainages have become more than 5 times more frequent in recent decades. These changes are likely related to the impacts of increased temperature and precipitation on thermokarst processes. Fifty-nine of the 170 intensively studied lakes showed either large bidirectional fluctuations or gradual cumulative declines. These changes affected a much smaller portion of OCF and were likely driven by interactions between increased precipitation and temperature and individual catchment characteristics. To anticipate landscape-scale changes in these systems, and assess their impact on hydrology, wildlife habitat, and carbon storage, field research is required to better characterize the mechanisms responsible for changes.

Monitoring Recent Fluctuations of the Southern Pool of Lake Chad Using Multiple Remote Sensing Data: Implications for Water Balance Analysis

“…Landsat TM/ETM+ images, because of their high spatial resolution (30 m), have been widely used to monitor the variations of water surface area [38][39][40]. In total, 904 Landsat TM/ETM+ images from 1991 to 2016 were obtained from the USGS Glovis data archive (http://glovis.usgs.gov).…”

“…The vivid spectral information provided by Landsat TM/ETM+ images has been widely used for mapping water surface area [38][39][40]. The basic logic of these studies is to highlight the difference between water bodies and other objects through the calculation of water indexes [48].…”

The Polar WRF Downscaled Historical and Projected Twenty-First Century Climate for the Coast and Foothills of Arctic Alaska

“…For example, the permafrost temperature in the western North American Arctic has warmed by 0.5-4 • C since the 1970s (Romanovsky et al, 2010;Grosse et al, 2011), resulting in active layer thickening (Kane et al, 1991;Grosse et al, 2016) and permafrost degradation (Jorgenson et al, 2006;Lantz and Kokelj, 2008;Liljedahl et al, 2016). Other changes include, but are not limited to, thermokarst lake drainage (Plug et al, 2008;Jones et al, 2011;Jones and Arp, 2015;Lantz and Turner, 2015), thinner lake ice (Arp et al, 2012;Alexeev et al, 2016), longer unfrozen Arctic lake surface (Brown and Duguay, 2010), more lake surface evaporation (Hinzman and Kane, 1992;Arp et al, 2015), and extended growing season (Hinzman et al, 2005;Tape et al, 2006;Bhatt et al, 2008;Chapin et al, 2012). Post et al (2009) pointed out that the amount and types of impacts are still underreported and the understanding of the underlying physical mechanisms are still lacking due to insufficient observations in the Arctic.…”

Size Distribution, Surface Coverage, Water, Carbon, and Metal Storage of Thermokarst Lakes in the Permafrost Zone of the Western Siberia Lowland

“…Several studies of thermokarst lakes in Alaska, Yukon, Scandinavia, and Siberia, were focused on monitoring the change in the lake area over the past 30-40 years, within relatively small regions [18,29,[41][42][43][44][45]. Remote sensing studies of the permafrost zone of western Siberia demonstrated that the number of newly formed small thermokarst lakes (0.5-5 ha) over the past three decades exceeds, by a factor of 20, the number of large lakes which tend to disappear during the same period [46].…”