Thermal modeling of three lakes within the continuous permafrost zone in Alaska using the LAKE 2.0 model

• Published in: Geoscientific Model Development Vol. 15; no. 19; pp. 7421 - 7448
• Main Authors: Clark, Jason A, Jafarov, Elchin E, Tape, Ken D, Jones, Benjamin M, Stepanenko, Victor
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 06-10-2022; Copernicus Publications
• Subjects: Air temperature; Albedo; Analysis; Arctic lakes; Biogeochemistry; Carbon; Catchment area; Catchment hydrology; Climate change; Depth; Eddy covariance; Efficiency; Gases; Global warming; Groundwater; Heat; Heat balance; Heat storage; Hydrology; Ice; Ice cover; Ice thickness; Lake ice; Lakes; Meteorological data; Modelling; One dimensional models; Permafrost; Perturbation; Phase transitions; Precipitation; Precipitation (Meteorology); Radiation; Radiation absorption; Remote sensing; Reservoirs; Resolution; Sediments; Sensitivity analysis; Short wave radiation; Simulation; Snow accumulation; Snow depth; Soil columns; Soil degradation; Soil depth; Solar radiation; Summer; Temporal resolution; Thawing; Thermal analysis; Thermal models; Thermodynamics; Thickness; Tundra; Vegetation; Vertical profiles; Water balance; Water balance (Hydrology); Water depth; Water temperature; Weather stations; Winter; Arctic; United States > US; Alaska; Arctic region
• ISSN: 1991-9603; 1991-959X; 1991-962X; 1991-9603; 1991-962X
• DOI: 10.5194/gmd-15-7421-2022

Lakes in the Arctic are important reservoirs of heat with
much lower albedo in summer and greater absorption of solar radiation than
surrounding tundra vegetation. In the winter, lakes that do not freeze to
their bed have a mean annual bed temperature >0 ∘C in
an otherwise frozen landscape. Under climate warming scenarios, we expect
Arctic lakes to accelerate thawing of underlying permafrost due to warming
water temperatures in the summer and winter. Previous studies of Arctic
lakes have focused on ice cover and thickness, the ice decay process,
catchment hydrology, lake water balance, and eddy covariance measurements,
but little work has been done in the Arctic to model lake heat balance. We
applied the LAKE 2.0 model to simulate water temperatures in three Arctic
lakes in northern Alaska over several years and tested the sensitivity of
the model to several perturbations of input meteorological variables
(precipitation, shortwave radiation, and air temperature) and several model
parameters (water vertical resolution, sediment vertical resolution, depth
of soil column, and temporal resolution). The LAKE 2.0 model is a
one-dimensional model that explicitly solves vertical profiles of water
state variables on a grid. We used a combination of meteorological data from
local and remote weather stations, as well as data derived from remote
sensing, to drive the model. We validated modeled water temperatures with
data of observed lake water temperatures at several depths over several
years for each lake. Our validation of the LAKE 2.0 model is a necessary
step toward modeling changes in Arctic lake ice regimes, lake heat balance,
and thermal interactions with permafrost. The sensitivity analysis shows us
that lake water temperature is not highly sensitive to small changes in air
temperature or precipitation, while changes in shortwave radiation and large
changes in precipitation produced larger effects. Snow depth and lake ice
strongly affect water temperatures during the frozen season, which dominates
the annual thermal regime of Arctic lakes. These findings suggest that
reductions in lake ice thickness and duration could lead to more heat
storage by lakes and enhanced permafrost degradation.