Diamictic sediments within high Arctic lake sediment cores: evidence for lake ice rafting along the lateral glacial margin

Sedimentology ◽  
2000 ◽  
Vol 47 (6) ◽  
pp. 1157-1179 ◽  
Author(s):  
I. Rod Smith
Keyword(s):  
Lake Sediment ◽  
Sediment Cores ◽  
High Arctic ◽  
Lake Ice ◽  
Arctic Lake ◽  
Ice Rafting

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 Harmonizing heterogeneous multi-proxy data from Arctic lake sediment records 

2021 ◽  
Author(s):  
Gregor Pfalz ◽  
Bernhard Diekmann ◽  
Johann-Christoph Freytag ◽  
Boris K. Biskaborn
Keyword(s):  
Lake Sediment ◽  
Sediment Cores ◽  
Interdisciplinary Approach ◽  
Heterogeneous Data ◽  
Statistical Investigation ◽  
The Arctic ◽  
Proxy Data ◽  
Arctic Lake ◽  
Global Database ◽  
Lake Systems

<p>Lake systems play a central role in broadening our knowledge about future trends in the Arctic, as their sediments store information on interactions between climate change, lake ontogeny, external abiotic sediment input, and biodiversity changes. In order to make reliable statements about future lake trajectories, we need sound multi-proxy data from different lakes across the Arctic. Various studies using data from repositories already showed the effectiveness of multi-proxy, multi-site investigations (e.g., Kaufman et al., 2020; PAGES 2k Consortium, 2017). However, there are still datasets from past coring expeditions to Arctic lake systems that are neither included in any of these repositories nor subject to any particular standard. When working with such data from heterogeneous sources, we face the challenge of dealing with data of different format, type, and structure. It is therefore necessary to transform such data into a uniform format to ensure semantic and syntactic comparability. In this talk, we present an interdisciplinary approach by transforming research data from different lake sediment cores into a coherent framework. Our approach adapts methods from the database field, such as developing entity-relationship (ER) diagrams, to understand the conceptual structure of the data independently of the source. Based on this knowledge, we developed a conceptual data model that allows scientists to integrate heterogeneous data into a common database. During the talk, we present further steps to prepare datasets for multi-site statistical investigation. To test our approach, we compiled and transformed a collection of published and unpublished paleolimnological data of Arctic lake systems into our proposed format. Additionally, we show our results from conducting a comparative analysis on a set of acquired data, hereby focusing on comparing total organic carbon and bromine content. We conclude that our harmonized dataset enables numerical inter-proxy and inter-lake comparison despite strong initial heterogeneity.</p><p> </p><p>[1]   D. S. Kaufman et al., “A global database of Holocene paleotemperature records,” Sci. Data, vol. 7, no. 115, pp. 1–34, 2020.</p><p>[2]   PAGES 2k Consortium, “A global multiproxy database for temperature reconstructions of the Common Era,” Sci. Data, vol. 4, no. 170088, pp. 1–33, 2017.</p>

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.

scholarly journals Quantitative and qualitative constraints on hind-casting the formation of multiyear lake-ice covers at Lake El'gygytgyn

2013 ◽  
Vol 9 (3) ◽  
pp. 1253-1269 ◽  
Author(s):  
M. Nolan
Keyword(s):  
Water Exchange ◽  
Sediment Cores ◽  
Ice Cover ◽  
Lake Ice ◽  
Ice Growth ◽  
Temperature Reduction ◽  
Air Temperatures ◽  
Lake El’Gygytgyn ◽  
Oxygen Conditions ◽  
Multiyear Ice

Abstract. Analysis of the 3.6 Ma, 318 m long sediment core from Lake El'gygytgyn suggests that the lake was covered by ice for millennia at a time for much of its history and therefore this paper uses a suite of existing, simple, empirical degree-day models of lake-ice growth and decay to place quantitative constraints on air temperatures needed to maintain a permanent ice cover on the lake. We also provide an overview of the modern climatological and physical processes that relate to lake-ice growth and decay as a basis for evaluating past climate and environmental conditions. Our modeling results indicate that modern annual mean air temperature would only have to be reduced by 3.3 °C ± 0.9 °C to initiate a multiyear ice cover and a temperature reduction of at least 5.5 °C ± 1.0 °C is likely needed to completely eliminate direct air–water exchange of oxygen, conditions that have been inferred at Lake El'gygytgyn from the analysis of sediment cores. Once formed, a temperature reduction of only 1–3 °C relative to modern may be all that is required to maintain multiyear ice. We also found that formation of multiyear ice covers requires that positive degree days are reduced by about half the modern mean, from about +608 to +322. A multiyear ice cover can persist even with summer temperatures sufficient for a two-month long thawing period, including a month above +4 °C. Thus, it is likely that many summer biological processes and some lake-water warming and mixing may still occur beneath multiyear ice-covers even if air–water exchange of oxygen is severely restricted.

The History of Human Impacts in the Clear Lake Watershed ( California) as Deduced from Lake Sediment Cores*

1999 ◽  
Author(s):  
Douglas Nelson ◽  
Alan Heyvaert ◽  
Laurent Meillier ◽  
Jae Kim ◽  
Xiaoping Li ◽  
...  
Keyword(s):  
Lake Sediment ◽  
Human Impacts ◽  
Sediment Cores ◽  
Clear Lake ◽  
History Of

scholarly journals Contrasting the ecological effects of decreasing ice cover versus accelerated glacial melt on the High Arctic's largest lake

2020 ◽  
Vol 287 (1929) ◽  
pp. 20201185
Author(s):  
Neal Michelutti ◽  
Marianne S. V. Douglas ◽  
Dermot Antoniades ◽  
Igor Lehnherr ◽  
Vincent L. St. Louis ◽  
...  
Keyword(s):  
Sediment Cores ◽  
Fold Increase ◽  
Mass Gain ◽  
Ecological Change ◽  
Diatom Assemblages ◽  
Lake Ice ◽  
Glacial Meltwater ◽  
Glacial Runoff ◽  
Common Era ◽  
Ecological Functioning

Lake Hazen, the High Arctic's largest lake, has received an approximately 10-fold increase in glacial meltwater since its catchment glaciers shifted from net mass gain to net mass loss in 2007 common era (CE), concurrent with recent warming. Increased glacial meltwater can alter the ecological functioning of recipient aquatic ecosystems via changes to nutrient budgets, turbidity and thermal regimes. Here, we examine a rare set of five high-resolution sediment cores collected in Lake Hazen between 1990 and 2017 CE to investigate the influence of increased glacial meltwater versus alterations to lake ice phenology on ecological change. Subfossil diatom assemblages in all cores show two major shifts over the past approximately 200 years including: (i) a proliferation of pioneering, benthic taxa at approximately 1900 CE from previously depauperate populations; and (ii) a rise in planktonic taxa beginning at approximately 1980 CE to present-day dominance. The topmost intervals from each sequentially collected core provide exact dates and demonstrate that diatom regime shifts occurred decades prior to accelerated glacial inputs. These data show that diatom assemblages in Lake Hazen are responding primarily to intrinsic lake factors linked to decreasing duration of lake ice and snow cover rather than to limnological impacts associated with increased glacial runoff.

Sign in / Sign up

Export Citation Format

Share Document