Contemporary (1951–2001) Evolution of Lakes in the Old Crow Basin, Northern Yukon, Canada: Remote Sensing, Numerical Modeling, and Stable Isotope Analysis

Abstract

this study reports on changes in the distribution, surface area, and modern water balance of lakes and ponds located in the Old Crow Basin, northern Yukon, over a 50-year period (1951 -2001), using aerial photographs, satellite imagery, a numerical lake model, and stable O-H isotope analysis. Results from the analysis of historical air photos (1951 and 1972) and a Landsat-7 Enhanced thematic Mapper (EtM+) image (2001) show an overall decrease (-3.5%) in lake surface area between 1951 and 2001. Large lakes typically decreased in extent over the study period, whereas ponds generally increased. Between 1951 and 1972, approximately 70% of the lakes increased in extent; however, between 1972 and 2001, 45% decreased in extent. These figures are corroborated by a numerical lake water balance simulation (P-E index) and stable O-H isotope analysis indicating that most lakes experienced a water deficit over the period 1988 -2001. These observed trends towards a reduction in lake surface area are mainly attributable to a warmer and drier climate. the modern decrease in lake levels corresponds well to changes in regional atmospheric teleconnection patterns (Arctic and Pacific Decadal oscillations). In 1977, the climate in the region switched from a predominantly cool and moist regime, associated with the increase in lake surface area, to a hot and dry one, thus resulting in the observed decrease in lake surface area. Although some lakes may have drained catastrophically by stream erosion or bank overflow, it is not possible to determine with certainty which lakes experienced such catastrophic drainage, since an interval of two decades separates the two air photo mosaics, and the satellite image was obtained almost 30 years after the second mosaic of air photos. key words: thaw lakes, lake levels, remote sensing, modeling, stable O-H isotopes, Old Crow, northern Yukon RÉSuMÉ. La présente étude fait état des changements caractérisant la répartition, l'étendue et le bilan hydrique contemporain des lacs et des étangs situés dans le bassin Old Crow, dans le nord du Yukon, sur une période de 50 ans (1951 -2001). L'étude s'est appuyée sur des photographies aériennes, l'imagerie satellitaire, un modèle numérique des lacs et l'analyse des isotopes stables O-H. D'après les résultats de l'analyse des photos aériennes historiques (1951 et 1972) et d'une image par capteur EtM+ (Enhanced thematic Mapper) de Landsat-7 (2001), il y a eu rétrécissement général (-3,5 %) de la surface des lacs entre 1951 et 2001. D'un point de vue général, l'étendue des grands lacs a diminué au cours de la période visée par l'étude, tandis que celle des étangs a augmenté. Entre 1951 et 1972, l'étendue d'environ 70 % des lacs s'est accrue, mais entre 1972 et 2001, l'étendue de 45 % des lacs a diminué.Ces données ont été corroborées au moyen de la simulation numérique du bilan hydrique des lacs (indice P-E) et de l'analyse des isotopes stables O-H, qui ont laissé entrevoir que la plupart des lacs ont enregistré un déficit en eau au cours de la période allant de...

Limnological evolution of Zelma Lake, a recently drained thermokarst lake in Old Crow Flats (Yukon, Canada)

“…For millennia, the Vuntut Gwitchin relied on the diverse network of lakes in OCF, which support waterfowl, fish, and other wildlife (Old Crow Flats Van Tat K'atr'anahtii Special Management Area Management Plan 2006). Lake drainage events are common in OCF (Labrecque et al 2009), and a recent remote sensing analysis identified that their frequency has increased markedly from 0.36 to 2.02 lakes · year -1 · 10 000 km -2 between 1950 and 2009, consistent with local observations of reduced water levels (Lantz and Turner 2015). The majority of lake drainage events in OCF are partial, leaving behind numerous residual waterbodies within the former lake basin (Lantz and Turner 2015).…”

PeRL: a circum-Arctic Permafrost Region Pond and Lake database

“…Studies have also used surface areas smaller than 5.0×10 4 m 2 (Labrecque et al, 2009) or 1.0×10 4 m 2 (Rautio et al, 2011) to distinguish ponds from lakes.…”

Freshwater ostracods (Crustacea) and environmental variability of polygon ponds in the tundra of the Indigirka Lowland, north-east Siberia

“…A similar decline in lake area and abundance has occurred in northern Siberia since 1973 owing to subsurface drainage through discontinuous permafrost (Smith et al 2005). Labreque et al (2009) observed a reduction in lake surface area at a study site in the northern Yukon Territory, Canada, since 1951. The lakes experienced a water deficit that is attributed to a warmer climate and less precipitation.…”