The role of snow cover in the warming of arctic permafrost

Abstract

[1] Air temperatures at high latitudes are expected to rise significantly as anthropogenic carbon builds up in the atmosphere. There is concern that warming of the ground in permafrost regions will result in additional release of carbon to the atmosphere. Recent emphasis has thus been on predicting the magnitude and spatial distribution of future warming at high latitudes. Modeling results show that changes in below ground temperatures can be influenced as much by temporal variations of snow cover as by changes in the near-surface air temperature. The recent (1983 -1998) changes in permafrost temperatures on the North Slope of Alaska are consistent with decadal scale variability in snow cover. The implication of these results is that a better understanding of how winter precipitation patterns at high latitudes will change over the coming decades is needed to comprehend evolving permafrost temperatures.

Modeling permafrost thaw and ecosystem carbon cycle under annual and seasonal warming at an Arctic tundra site in Alaska

“…The high sensitivities of simulated soil temperature in response to root biomass and clay content are consistent with former findings that these two properties determined soil heat conductivity and capacity, and soil water dynamics, thus regulated the energy penetrating into the soil and also the energy emission from the ground surface [Stieglitz et al, 2003;Langer et al, 2011]. We specifically analyzed stepwise warming effects on soil temperature increase and ecosystem C balance in 2009 when observations are available.…”

“…As a key variable in permafrost environment, increasing soil temperature under climate warming can accelerate snow disappearance, degrade snow insulation, increase belowground microbial activities, and alter ecosystem C balance [Stieglitz et al, 2003;Dorrepaal et al, 2004;Zhang, 2005;Langer et al, 2011;O'Donnell et al, 2011;Li et al, 2012Li et al, , 2013. In a separate simulation, a greater soil temperature (i.e., 1.5°C as observed in the field warming experiment) led to a similar percentage increase in wintertime respiration.…”

Ice-cored moraine degradation mapped and quantified using an unmanned aerial vehicle: A case study from a polythermal glacier in Svalbard

“…A further confounding factor is snow-cover which is known to limit the influence of atmospheric heat on ground temperature (Stieglitz et al, 2003). Whilst in winter snow may permit higher ground temperature in relation to mean air temperatures (Stieglitz et al, 2003), late lying snow is likely to play an additional role limiting the susceptibility of buried-ice to surface warming.…”

“…Whilst in winter snow may permit higher ground temperature in relation to mean air temperatures (Stieglitz et al, 2003), late lying snow is likely to play an additional role limiting the susceptibility of buried-ice to surface warming. Further work investigating the influence of snow cover…”

The contribution of snow condition trends to future ground climate

“…Since a snow-covered surface reflects a much large portion of the incoming solar radiation than a snow-free surface, a lengthening or shortening of the snowseason will alter how much incoming solar energy is absorbed by the ground, also affecting soil temperatures. Prior studies, both modeling and observation based, suggest that soil temperature change (at 10-20 m depth) over the latter part of the twentieth and early part of the twentyfirst century can be attributed roughly equally to air temperature and snow depth trends or variations (Zhang et al 2001;Stieglitz et al 2003;Osterkamp 2007b). Osterkamp (2007a) concludes that modeling studies are required to assess the relative role of snow versus air temperature effects on soil temperature trends.…”