scholarly journals The fate of lake ice in the North American Arctic

2011 ◽  
Vol 5 (4) ◽  
pp. 1775-1834 ◽  
Author(s):  
L. C. Brown ◽  
C. R. Duguay
Keyword(s):  
North American ◽  
Climate Model ◽  
Climate Scenario ◽  
Ice Cover ◽  
Ice Thickness ◽  
Lake Ice ◽  
Climate Conditions ◽  
The North ◽  
North American Arctic ◽  
Ice Phenology

Abstract. Lakes comprise a large portion of the surface cover in northern North America forming an important part of the cryosphere. The timing of lake ice phenological events (e.g. break-up/freeze-up) are useful indicators of climate variability and change, which is of particular relevance in environmentally sensitive areas such as the North American Arctic. Further alterations to the present day ice regime could result in major ecosystem changes, such as species shifts and the disappearance of perennial ice cover. Lake ice models are a valuable tool for examining the response of lake ice cover to changing climate conditions. The use of future climate scenario data in these models can provide information on the potential changes in ice phenology, ice thickness and composition. The Canadian Lake Ice Model (CLIMo) was used to simulate lake ice phenology across the North American Arctic from 1961–2100 using climate scenarios produced by the Canadian Regional Climate Model (CRCM). Results from the 1961–1990 time period were validated using 15 locations across the Canadian Arctic, with both in situ ice cover observations from the Canadian Ice Database as well as additional ice cover simulations using nearby weather station data. Projected changes to the ice cover using the 30 yr mean data between 1961–1990 and 2041–2070 suggest a shift towards shorter ice cover durations by an average of just over 3 weeks, with a 25 cm average reduction of the total ice thickness – varying based on location, lake depth and snow cover amounts.

scholarly journals The fate of lake ice in the North American Arctic

2011 ◽  
Vol 5 (4) ◽  
pp. 869-892 ◽  
Author(s):  
L. C. Brown ◽  
C. R. Duguay
Keyword(s):  
Snow Cover ◽  
North American ◽  
Climate Model ◽  
Regional Climate ◽  
Ice Cover ◽  
Lake Ice ◽  
The North ◽  
North American Arctic ◽  
Break Up ◽  
Perennial Ice

Abstract. Lakes comprise a large portion of the surface cover in northern North America, forming an important part of the cryosphere. The timing of lake ice phenological events (e.g. break-up/freeze-up) is a useful indicator of climate variability and change, which is of particular relevance in environmentally sensitive areas such as the North American Arctic. Further alterations to the present day ice regime could result in major ecosystem changes, such as species shifts and the disappearance of perennial ice cover. The Canadian Lake Ice Model (CLIMo) was used to simulate lake ice phenology across the North American Arctic from 1961–2100 using two climate scenarios produced by the Canadian Regional Climate Model (CRCM). Results from the 1961–1990 time period were validated using 15 locations across the Canadian Arctic, with both in situ ice cover observations from the Canadian Ice Database as well as additional ice cover simulations using nearby weather station data. Projected changes to the ice cover using the 30-year mean data between 1961–1990 and 2041–2070 suggest a shift in break-up and freeze-up dates for most areas ranging from 10–25 days earlier (break-up) and 0–15 days later (freeze-up). The resulting ice cover durations show mainly a 10–25 day reduction for the shallower lakes (3 and 10 m) and 10–30 day reduction for the deeper lakes (30 m). More extreme reductions of up to 60 days (excluding the loss of perennial ice cover) were shown in the coastal regions compared to the interior continental areas. The mean maximum ice thickness was shown to decrease by 10–60 cm with no snow cover and 5–50 cm with snow cover on the ice. Snow ice was also shown to increase through most of the study area with the exception of the Alaskan coastal areas.

Simulation of North American lake-ice cover characteristics under contemporary and future climate conditions

2011 ◽  
Vol 32 (5) ◽  
pp. 695-709 ◽  
Author(s):  
Yonas Dibike ◽  
Terry Prowse ◽  
Barrie Bonsal ◽  
Laurent de Rham ◽  
Tuomo Saloranta
Keyword(s):  
North American ◽  
Ice Cover ◽  
Future Climate ◽  
Lake Ice ◽  
Climate Conditions ◽  
Lake Ice Cover

scholarly journals Response of ice cover on shallow lakes of the North Slope of Alaska to contemporary climate conditions (1950–2011): radar remote sensing and numerical modeling data analysis

2013 ◽  
Vol 7 (4) ◽  
pp. 3783-3821 ◽  
Author(s):  
C. M. Surdu ◽  
C. R. Duguay ◽  
L. C. Brown ◽  
D. Fernández Prieto
Keyword(s):  
Shallow Lakes ◽  
Ice Cover ◽  
Arctic Lakes ◽  
North Slope ◽  
Lake Ice ◽  
Climate Conditions ◽  
The North ◽  
North Slope Of Alaska ◽  
Sar Data ◽  
Ice Model

Abstract. Air temperature and winter precipitation changes over the last five decades have impacted the timing, duration, and thickness of the ice cover on Arctic lakes as shown by recent studies. In the case of shallow tundra lakes, many of which are less than 3 m deep, warmer climate conditions could result in thinner ice covers and consequently, to a smaller fraction of lakes freezing to their bed in winter. However, these changes have not yet been comprehensively documented. The analysis of a 20 yr time series of ERS-1/2 synthetic aperture radar (SAR) data and a numerical lake ice model were employed to determine the response of ice cover (thickness, freezing to the bed, and phenology) on shallow lakes of the North Slope of Alaska (NSA) to climate conditions over the last six decades. Analysis of available SAR data from 1991–2011, from a sub-region of the NSA near Barrow, shows a reduction in the fraction of lakes that freeze to the bed in late winter. This finding is in good agreement with the decrease in ice thickness simulated with the Canadian Lake Ice Model (CLIMo), a lower fraction of lakes frozen to the bed corresponding to a thinner ice cover. Observed changes of the ice cover show a trend toward increasing floating ice fractions from 1991 to 2011, with the greatest change occurring in April, when the grounded ice fraction declined by 22% (α = 0.01). Model results indicate a trend toward thinner ice covers by 18–22 cm (no-snow and 53% snow depth scenarios, α = 0.01) during the 1991–2011 period and by 21–38 cm (α = 0.001) from 1950–2011. The longer trend analysis (1950–2011) also shows a decrease in the ice cover duration by ∼24 days consequent to later freeze-up dates by 5.9 days (α = 0.1) and earlier break-up dates by 17.7–18.6 days (α = 0.001).

scholarly journals Response of ice cover on shallow lakes of the North Slope of Alaska to contemporary climate conditions (1950–2011): radar remote-sensing and numerical modeling data analysis

2014 ◽  
Vol 8 (1) ◽  
pp. 167-180 ◽  
Author(s):  
C. M. Surdu ◽  
C. R. Duguay ◽  
L. C. Brown ◽  
D. Fernández Prieto
Keyword(s):  
Remote Sensing ◽  
Shallow Lakes ◽  
Ice Cover ◽  
North Slope ◽  
Lake Ice ◽  
Climate Conditions ◽  
The North ◽  
North Slope Of Alaska ◽  
Sar Data ◽  
Ice Model

Abstract. Air temperature and winter precipitation changes over the last five decades have impacted the timing, duration, and thickness of the ice cover on Arctic lakes as shown by recent studies. In the case of shallow tundra lakes, many of which are less than 3 m deep, warmer climate conditions could result in thinner ice covers and consequently, in a smaller fraction of lakes freezing to their bed in winter. However, these changes have not yet been comprehensively documented. The analysis of a 20 yr time series of European remote sensing satellite ERS-1/2 synthetic aperture radar (SAR) data and a numerical lake ice model were employed to determine the response of ice cover (thickness, freezing to the bed, and phenology) on shallow lakes of the North Slope of Alaska (NSA) to climate conditions over the last six decades. Given the large area covered by these lakes, changes in the regional climate and weather are related to regime shifts in the ice cover of the lakes. Analysis of available SAR data from 1991 to 2011, from a sub-region of the NSA near Barrow, shows a reduction in the fraction of lakes that freeze to the bed in late winter. This finding is in good agreement with the decrease in ice thickness simulated with the Canadian Lake Ice Model (CLIMo), a lower fraction of lakes frozen to the bed corresponding to a thinner ice cover. Observed changes of the ice cover show a trend toward increasing floating ice fractions from 1991 to 2011, with the greatest change occurring in April, when the grounded ice fraction declined by 22% (α = 0.01). Model results indicate a trend toward thinner ice covers by 18–22 cm (no-snow and 53% snow depth scenarios, α = 0.01) during the 1991–2011 period and by 21–38 cm (α = 0.001) from 1950 to 2011. The longer trend analysis (1950–2011) also shows a decrease in the ice cover duration by ~24 days consequent to later freeze-up dates by 5.9 days (α = 0.1) and earlier break-up dates by 17.7–18.6 days (α = 0.001).

scholarly journals The influence of albedo parameterization for improved lake ice simulation

2020 ◽  
Author(s):  
Alexis L. Robinson ◽  
Sarah S. Ariano ◽  
Laura C. Brown
Keyword(s):  
Field Measurements ◽  
Time Lapse ◽  
Ice Cover ◽  
High Arctic ◽  
Arctic Lakes ◽  
Ice Thickness ◽  
Lake Ice ◽  
Temperate Region ◽  
Climate Conditions ◽  
Arctic Lake

Abstract. Lake ice models can be used to study the latitudinal differences of current and projected changes in ice covered lakes under a changing climate. The Canadian Lake Ice Model (CLIMo) is a one-dimensional freshwater ice cover model that simulates Arctic and sub-Arctic lake ice cover well. Modelling ice cover in temperate regions has presented challenges due to the differences in composition between northern and temperate ice. This study presents a comparison of measured and modelled ice regimes, with a focus on refining CLIMo for temperate regions. The study sites include two temperate region lakes (MacDonald Lake and Clear Lake, Central Ontario) and two High Arctic lakes (Resolute Lake and Small Lake, Nunavut) where climate and ice cover information have been recorded over three seasons. The ice cover simulations were validated with a combination of time lapse imagery, field measurements of snow depth, snow density, ice thickness and albedo data, and historical ice records from the Canadian Ice Database (for Resolute Lake). Simulations of the High Arctic ice cover show good agreement with previous studies for ice-on and ice-off dates (MAE 6 to 8 days). Unadjusted simulations for the temperate region lakes show both an underestimation in ice thickness (~ 4 to 18 cm) and ice-off timing (~ 25 to 30 days). Field measurements were used to adjust the albedo parameterization used in CLIMo, which resulted in improvements to both simulated ice thickness, within 0.1 cm to 10 cm of manual measurements, and ice-off timing, within 1 to 7 days of observations. These findings suggest regionally specific measurements of albedo can improve the accuracy of lake ice simulations. These results further our knowledge regarding of the response of temperate and High Arctic lake ice regimes to climate conditions.

scholarly journals Modelling Lake Ice Phenology with an Examination of Satellite-Detected Subgrid Cell Variability

2012 ◽  
Vol 2012 ◽  
pp. 1-19 ◽  
Author(s):  
Laura C. Brown ◽  
Claude R. Duguay
Keyword(s):  
Climate Model ◽  
Regional Climate ◽  
Future Climate ◽  
Cell Level ◽  
Lake Ice ◽  
Climate Conditions ◽  
One Dimensional ◽  
The Mean ◽  
Ice Model ◽  
Ice Phenology

Lake ice was simulated for the province of Quebec, Canada, for both contemporary and future climate conditions using a one-dimensional thermodynamic ice model. The model was forced with NARR data (32 km) and both the daily IMS product (4 km) and the MODIS snow product (500 m) were assessed for their utility at determining lake ice phenology at the subgrid cell level (based on the 32 km NARR grid). Both products were useful for detecting ice-off; however, the MODIS product was advantageous for detecting ice-on, mainly due to the finer resolution and resulting spatial detail. The subgrid cell variability in ice-on/off dates was typically less than 2% of the mean, although it ranged up to 10% for some grid cells. The simulations were found to be within the satellite-detected subgrid cell variability: 62% of the time for ice-off and 80% of the time for ice-on. Forcing the model with future climate scenarios from the Canadian Regional Climate Model predicts the regional ice cover durations will decrease by up to 50 days from the current 1981–2010 means to the 2041–2070 means and decrease from 15 to nearly 100 days shorter from the current means to the 2071–2100 means.

scholarly journals The Influence of Snow and Ice Albedo towards Improved Lake Ice Simulations

Hydrology ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 11
Author(s):  
Alexis L. Robinson ◽  
Sarah S. Ariano ◽  
Laura C. Brown
Keyword(s):  
Field Measurements ◽  
Ice Cover ◽  
High Arctic ◽  
Arctic Lakes ◽  
Ice Thickness ◽  
Lake Ice ◽  
Temperate Region ◽  
Climate Conditions ◽  
Arctic Lake ◽  
Lake Ice Cover

Lake ice models are a vital tool for studying the response of ice-covered lakes to changing climates throughout the world. The Canadian Lake Ice Model (CLIMo) is a one-dimensional freshwater ice cover model that simulates Arctic and sub-Arctic lake ice cover well. Modelling ice cover in temperate regions has presented challenges due to the differences in ice composition between northern and temperate region lake ice. This study presents a comparison of measured and modelled ice regimes, with a focus on refining CLIMo for temperate regions. The study sites include two temperate region lakes (MacDonald Lake and Clear Lake, Central Ontario) and two High Arctic lakes (Resolute Lake and Small Lake, Nunavut) where climate and ice cover information have been recorded over three seasons. The ice cover simulations were validated with a combination of time lapse imagery, field measurements of snow depth, snow density, ice thickness and albedo data, and historical ice records from the Canadian Ice Database (for Resolute Lake). Simulations of High Arctic lake ice cover show good agreement with previous studies for ice-on and ice-off dates (MAE 6 to 8 days). Unadjusted simulations for the temperate region lakes show good ice-on timing, but an under-representation of ice thickness, and earlier complete ice-off timing (~3 to 5 weeks). Field measurements were used to adjust the albedo values used in CLIMo, which resulted in improvements to both simulated ice thickness (~3 cm MAE compared to manual measurements), and ice-off timing, within 0 to 7 days (2 days MAE) of observations. These findings suggest regionally specific measurements of albedo can improve the accuracy of lake ice simulations, which further our knowledge of the response of temperate and High Arctic lake ice regimes to climate conditions.

Politics and Development in the North American Arctic

2021 ◽  
Author(s):  
Roman S. Czarny ◽  
Magdalena Tomala ◽  
Iwona Wrońska
Keyword(s):  
North American ◽  
The North ◽  
North American Arctic

scholarly journals Long-term changes of the ice regime of rivers in Latvia

2016 ◽  
Vol 47 (4) ◽  
pp. 782-798
Author(s):  
Inese Latkovska ◽  
Elga Apsīte ◽  
Didzis Elferts
Keyword(s):  
Regional Differences ◽  
Severity Index ◽  
Ice Cover ◽  
Ice Thickness ◽  
Positive Trend ◽  
The West ◽  
Climate Conditions ◽  
Long Term Changes ◽  
Ice Regime

The ice regime of rivers is considered a sensitive indicator of climate change. This paper summarises the results of research on the long-term changes in the ice regime parameters under changing climate conditions and their regional peculiarities in Latvia from 1945 to 2012. The ice cover duration on Latvian rivers has decreased during recent decades. The research results demonstrated that there is a positive trend as regards the formation of the ice cover and in 31.8% of the cases the trend is statistically significant at p < 0.05. As regards the breaking up of ice, there is a statistically significant negative trend in 93.2% of the cases at p < 0.05. This indicates an earlier ice break-up date, which in turn, displays a strong correlation with the increase of the air temperature. The same pattern applies to the reduction of the length of ice cover (a statistically significant trend in 86.4% of the cases at p < 0.05). In approximately 60% of the cases, there is a statistically significant reduction of the ice thickness. The estimated winter severity index indicates warmer winters over the last 20 years as well as regional differences in the west–east direction.

scholarly journals Fingerprints of changes in the terrestrial carbon cycle in response to large reorganizations in ocean circulation

2010 ◽  
Vol 6 (5) ◽  
pp. 1811-1852 ◽  
Author(s):  
A. Bozbiyik ◽  
M. Steinacher ◽  
F. Joos ◽  
T. F. Stocker
Keyword(s):  
Carbon Cycle ◽  
Ocean Circulation ◽  
North Atlantic ◽  
Climate Model ◽  
Carbon Stocks ◽  
Meridional Overturning Circulation ◽  
Climate Conditions ◽  
Tropical Regions ◽  
The North ◽  
Northern Latitudes

Abstract. CO2 and carbon cycle changes in the land, ocean and atmosphere are investigated using the comprehensive carbon cycle-climate model NCAR CSM1.4-carbon. Ensemble simulations are forced with freshwater perturbations applied at the North Atlantic and Southern Ocean deep water formation sites under pre-industrial climate conditions. As a result, the Atlantic Meridional Overturning Circulation reduces in each experiment to varying degrees. The physical climate fields show changes that are well documented in the literature but there is a clear distinction between northern and southern perturbations. Changes in the physical variables affect, in return, the land and ocean biogeochemical cycles and cause a reduction, or an increase, in the atmospheric CO2 by up to 20 ppmv, depending on the location of the perturbation. In the case of a North Atlantic perturbation, the land biosphere reacts with a strong reduction in carbon stocks in some tropical locations and in high northern latitudes. In contrast, land carbon stocks tend to increase in response to a southern perturbation. The ocean is generally a sink of carbon although large re-organizations occur throughout various basins. The response of the land biosphere is strongest in the tropical regions due to a shift of the Intertropical Convergence Zone. The carbon fingerprints of this shift, either to the south or to the north depending on where the freshwater is applied, can be found most clearly in South America. For this reason, a compilation of various paleoclimate proxy records of Younger Dryas precipitation changes are compared with our model results.

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