scholarly journals Air Bubble Stratigraphy of Lake Ice Covers

1983 ◽  
Vol 4 ◽  
pp. 299-299
Author(s):  
Richard Heron
Keyword(s):  
Bubble Formation ◽  
Ice Cover ◽  
Air Bubbles ◽  
Lake Ice ◽  
Daily Growth ◽  
Local Conditions ◽  
Small Lake ◽  
Ice Growth ◽  
Bubble Characteristics ◽  
Bubble Layers

Lake ice often has inclusions of air bubbles and their presence affects the thermal, mechanical, optical and other physical properties of the ice cover. Vertical variation in the characteristics of the bubbles suggests that their characteristics should be related to the rate of ice growth at the time of formation and therefore reflect past meteorological conditions.The laboratory studies of Carte (1961) and Bari and Hallett (1974) demonstrated that the rate of ice growth affects the size, shape and distribution of bubbles and the porosity of the ice. Their results were generally supported by the field study of Gow and Langston (1977), but Swinzow (1966) found no relationship between bubble characteristics and the rate of ice growth.Freeze-up and initial ice growth were monitored at Small Lake, Resolute, NWT, Canada, in 1978 to determine what diagnostic information night he obtained fror,) the inclusion stratigraphy of the ice cover. Additional samples were collected from five other lakes in the Resolute area, a shallow lake near Hamilton, Ontario, and two lakes near Huntsville, Ontario. Daily ice samples were removed from the ice cover of Small Lake and the inclusion stratigraphy was mapped. A typical ice sample shows diurnal sequences of bubbly and bubble-free ice. The inclusion layers, 1 to 5 mm thick, were formed near midday and were separated by 10 to 15 mm of clear, bubble-free ice. All samples were missing at least one inclusion stratum. There was a wide variety of bubble types and sizes, and non-gaseous inclusions, believed to be algae, were noted in some of the bubble layers. The hourly rate of ice growth was calculated using a modified Stefan equation. No relationship between the bubble characteristics and the rate of ice growth was obtained. The influence of the algae and the absorption of solar radiation by the water are probably responsible for the diurnal cycle of bubble formation by influencing nucleation. The absorbed radiation will warm the water and decrease the amount of air that the water can dissolve, thus making more air available for bubble growth. The algae will also change the concentrations of dissolved gases and act as nucleating agents.Cores taken from Small Lake in spring showed large cylindrical bubbles in the lower meter of the ice cover which had a thickness of 2.4 m. An inverse relationship between porosity and rate of ice growth was observed for these bubbles.Ice samples taken from the other lakes in the Resolute area either showed no inclusions at all or exhibited fewer diurnal inclusion sequences. Using a general bubble stratigraphy obtained from Small Lake it is possible to correlate some inclusion layers in samples taken from lakes that are 15 km apart.The samples from Hamilton also showed diurnal stratigraphie sequences except that the spacing between the bubble layers was more variable due to a larger range of daily growth rates. However, the two lakes near Huntsville had a detailed bubble stratigraphy, with little clear ice and no evidence of diurnal variation. The bubble layers in the ice from the two lakes could be easily matched, although they are 15 km apart.This study shows that bubble layers formed in a growing ice cover may be used to reveal some aspects of the history of the growth of the ice cover, although the applicability depends greatly on local conditions. Additional studies are required to understand the mechanisms by which air bubbles and algae are incorporated into lake ice.

scholarly journals Air Bubble Stratigraphy of Lake Ice Covers

1983 ◽  
Vol 4 ◽  
pp. 299
Author(s):  
Richard Heron
Keyword(s):  
Bubble Formation ◽  
Ice Cover ◽  
Air Bubbles ◽  
Lake Ice ◽  
Daily Growth ◽  
Local Conditions ◽  
Small Lake ◽  
Ice Growth ◽  
Bubble Characteristics ◽  
Bubble Layers

Lake ice often has inclusions of air bubbles and their presence affects the thermal, mechanical, optical and other physical properties of the ice cover. Vertical variation in the characteristics of the bubbles suggests that their characteristics should be related to the rate of ice growth at the time of formation and therefore reflect past meteorological conditions.The laboratory studies of Carte (1961) and Bari and Hallett (1974) demonstrated that the rate of ice growth affects the size, shape and distribution of bubbles and the porosity of the ice. Their results were generally supported by the field study of Gow and Langston (1977), but Swinzow (1966) found no relationship between bubble characteristics and the rate of ice growth.Freeze-up and initial ice growth were monitored at Small Lake, Resolute, NWT, Canada, in 1978 to determine what diagnostic information night he obtained fror,) the inclusion stratigraphy of the ice cover. Additional samples were collected from five other lakes in the Resolute area, a shallow lake near Hamilton, Ontario, and two lakes near Huntsville, Ontario. Daily ice samples were removed from the ice cover of Small Lake and the inclusion stratigraphy was mapped. A typical ice sample shows diurnal sequences of bubbly and bubble-free ice. The inclusion layers, 1 to 5 mm thick, were formed near midday and were separated by 10 to 15 mm of clear, bubble-free ice. All samples were missing at least one inclusion stratum. There was a wide variety of bubble types and sizes, and non-gaseous inclusions, believed to be algae, were noted in some of the bubble layers. The hourly rate of ice growth was calculated using a modified Stefan equation. No relationship between the bubble characteristics and the rate of ice growth was obtained. The influence of the algae and the absorption of solar radiation by the water are probably responsible for the diurnal cycle of bubble formation by influencing nucleation. The absorbed radiation will warm the water and decrease the amount of air that the water can dissolve, thus making more air available for bubble growth. The algae will also change the concentrations of dissolved gases and act as nucleating agents.Cores taken from Small Lake in spring showed large cylindrical bubbles in the lower meter of the ice cover which had a thickness of 2.4 m. An inverse relationship between porosity and rate of ice growth was observed for these bubbles.Ice samples taken from the other lakes in the Resolute area either showed no inclusions at all or exhibited fewer diurnal inclusion sequences. Using a general bubble stratigraphy obtained from Small Lake it is possible to correlate some inclusion layers in samples taken from lakes that are 15 km apart.The samples from Hamilton also showed diurnal stratigraphie sequences except that the spacing between the bubble layers was more variable due to a larger range of daily growth rates. However, the two lakes near Huntsville had a detailed bubble stratigraphy, with little clear ice and no evidence of diurnal variation. The bubble layers in the ice from the two lakes could be easily matched, although they are 15 km apart.This study shows that bubble layers formed in a growing ice cover may be used to reveal some aspects of the history of the growth of the ice cover, although the applicability depends greatly on local conditions. Additional studies are required to understand the mechanisms by which air bubbles and algae are incorporated into lake ice.

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.

scholarly journals Terms and conditions of high-mountain lake ice-cover chemistry (Carpathians, Poland)

2015 ◽  
Vol 61 (230) ◽  
pp. 1207-1212 ◽  
Author(s):  
Iwona Kurzyca ◽  
Adam Choiński ◽  
Joanna Pociask-Karteczka ◽  
Agnieszka Lawniczak ◽  
Marcin Frankowski
Keyword(s):  
Water Body ◽  
Ice Cover ◽  
Multilayered Structure ◽  
Mountain Lake ◽  
High Mountain ◽  
Lake Ice ◽  
High Mountain Lake ◽  
Spatial Diversification ◽  
The Tatra Mountains

AbstractWe discuss the results of an investigation of the chemical composition of the ice cover on the high-mountain lake Morskie Oko in the Tatra Mountains, Carpathians, Poland. In the years 2007–13, the ice cover was characterized by an average duration of 6 months, a thickness range of 0.40–1.14 m, and a multilayered structure with water or slush inclusion. In water from the melted ice cover, chloride (max. 69%) and sulphate (max. 51%) anions and ammonium (max. 66%) and calcium (max. 78%) cations predominated. Different concentrations of ions (F−, Cl−, NO3−, SO42−, Na+, K+, Mg2+, Ca2+, NH4+) in the upper, middle and bottom layers of ice were observed, along with long-term variability and spatial diversification within the ice layer over the lake. Snowpack lying on the ice and the water body under the ice were also investigated, and the influence on the ice cover of certain ions in elevated concentrations was observed (e.g. Cl− in the upper ice cover and the snowpack, and Ca2+ in the bottom ice cover and water body).

scholarly journals Big Questions, Few Answers About What Happens Under Lake Ice

Eos ◽  
2020 ◽  
Vol 101 ◽  
Author(s):  
Stephanie Hampton ◽  
Stephen Powers ◽  
Shawn Devlin ◽  
Diane McKnight
Keyword(s):  
Ice Cover ◽  
Lake Ice ◽  
Cold Temperatures

Scientists long eschewed studying lakes in winter, expecting that cold temperatures and ice cover limited activity below the surface. Recent findings to the contrary are changing limnologists’ views.

Lake ice phenology changes in the northern hemisphere

2021 ◽  
Author(s):  
Yubao Qiu ◽  
Xingxing Wang ◽  
Matti Leppäranta ◽  
Bin Cheng ◽  
Yixiao Zhang
Keyword(s):  
Remote Sensing ◽  
North America ◽  
Northern Hemisphere ◽  
Ice Cover ◽  
Passive Microwave ◽  
Lake Area ◽  
Lake Ice ◽  
Northern Tibetan Plateau ◽  
Break Up ◽  
Ice Phenology

<p>Lake-ice phenology is an essential indicator of climate change impact for different regions (Livingstone, 1997; Duguay, 2010), which helps understand the regional characters of synchrony and asynchrony. The observation of lake ice phenology includes ground observation and remote sensing inversion. Although some lakes have been observed for hundreds of years, due to the limitations of the observation station and the experience of the observers, ground observations cannot obtain the lake ice phenology of the entire lake. Remote sensing has been used for the past 40 years, in particular, has provided data covering the high mountain and high latitude regions, where the environment is harsh and ground observations are lacking. Remote sensing also provides a unified data source and monitoring standard, and the possibility of monitoring changes in lake ice in different regions and making comparisons between them. The existing remote sensing retrieval products mainly cover North America and Europe, and data for Eurasia is lacking (Crétaux et al., 2020).</p><p>Based on the passive microwave, the lake ice phenology of 522 lakes in the northern hemisphere during 1978-2020 was obtained, including Freeze-Up Start (FUS), Freeze-Up End (FUE), Break-Up Start (BUS), Break-Up End (BUE), and Ice Cover Duration (ICD). The ICD is the duration from the FUS to the BUE, which can directly reflect the ice cover condition. At latitudes north of 60°N, the average of ICD is approximately 8-9 months in North America and 5-6 months in Eurasia. Limited by the spatial resolution of the passive microwave, lake ice monitoring is mainly in Northern Europe. Therefore, the average of ICD over Eurasia is shorter, while the ICD is more than 6 months for most lakes in Russia. After 2000, the ICD has shown a shrinking trend, except northeastern North America (southeast of the Hudson Bay) and the northern Tibetan Plateau. The reasons for the extension of ice cover duration need to be analyzed with parameters, such as temperature, the lake area, and lake depth, in the two regions.</p>

scholarly journals Radiation Transmittance through lake ice in the 400–700 nm Range

1981 ◽  
Vol 27 (95) ◽  
pp. 57-66 ◽  
Author(s):  
S. J. Bolsenga
Keyword(s):  
Snow Cover ◽  
Ice Cover ◽  
Atmospheric Conditions ◽  
Lake Ice ◽  
Solar Altitude ◽  
Ice Surface ◽  
New Information ◽  
Cloudy Atmosphere ◽  
Abrupt Changes ◽  
Ann Arbor

AbstractSignificant new information on radiation transmittance through ice in the photosynthetically active range (400–700 nm) has been collected at an inland lake near Ann Arbor, Michigan, U.S.A., and at one site on the Great Lakes (lat. 46° 46´ N., long. 84° 57´ W.). Radiation transmittance through clear, refrozen slush, and brash ice varied according to snow cover, ice type, atmospheric conditions, and solar altitude.Snow cover caused the greatest diminution of radiation. During periods of snow melt, radiation transmittance through snow-covered ice surfaces increased slightly. Moderate diurnal variations of radiation transmittance (about 5%) are attributed to solar altitude changes and associated changes in the direct- diffuse balance of solar radiation combined with the type of ice surface studied. Variations in radiation transmittance of nearly 20% over short periods of time are attributed to abrupt changes from a clear to a cloudy atmosphere.A two-layer reflectance–transmittance model illustrates the interaction of layers in an ice cover such as snow or frost overlying clear ice. Upper layers of high reflectance have considerable control on the overall transmittance and reflectance of an ice cover.

scholarly journals Calving Seasonality Associated With Melt‐Undercutting and Lake Ice Cover

2020 ◽  
Vol 47 (8) ◽  
Author(s):  
Joseph Mallalieu ◽  
Jonathan L. Carrivick ◽  
Duncan J. Quincey ◽  
Mark W. Smith
Keyword(s):  
Ice Cover ◽  
Lake Ice ◽  
Lake Ice Cover

scholarly journals The Effect of Finite Heat Content and Thermal Diffusion on the Growth of a Sea-Ice Cover

1964 ◽  
Vol 5 (39) ◽  
pp. 315-324 ◽  
Author(s):  
Peter Schwerdtfeger
Keyword(s):  
Thermal Diffusivity ◽  
Sea Ice ◽  
Basic Equation ◽  
Heat Content ◽  
Ice Cover ◽  
Hudson Bay ◽  
Growth Equation ◽  
Ice Growth ◽  
Classical Work ◽  
Practical Analysis

AbstractThe practical analysis of the growth of a sea-ice cover is discussed with initial reference to the classical work of Stefan, whose basic equation connecting surface temperature with the growth of a uniform ice cover of negligible specific heat and hence infinite diffusivity is extended to cover “real” cases. The separate effects of a finite heat content and thermal diffusivity are derived theoretically and semi-empirically respectively, and combined in a more general ice-growth equation which is then tested in the analysis of annual sea-ice growth on Hudson Bay.

scholarly journals Note On Correlation Coefficients Derived from Cumulative Distributions with Reference to Glaciological Studies

1971 ◽  
Vol 10 (58) ◽  
pp. 145-147 ◽  
Author(s):  
J.T. Andrews ◽  
B.D. Faiiey ◽  
D. Alford
Keyword(s):  
Physical Interpretation ◽  
Standard Error ◽  
Correlation Coefficients ◽  
Random Numbers ◽  
Degree Days ◽  
Lake Ice ◽  
Ice Growth ◽  
Functional Relationships

Abstract In many areas of glaciology, cumulative degree days, either positive or negative, are regressed against another cumulative value, such as ablation or lake-ice growth. Very strong functional relationships are frequently found with high correlation coefficients. This note shows that, if pairs of random numbers are cumulated, the resulting correlation coefficients are extremely high with a Fisher transformed mean of r = 0.986 and standard error of ±0.001 (based on 50 individual computations of r which in turn were based on 20 cumulated pairs of random numbers between 0 and 99). These results indicate that caution must be exercised in the physical interpretation of data of this kind.

Improved Patient Safety Due to Catheter-Based Gas Bubble Removal During TURBT

2020 ◽  
Vol 9 (2) ◽  
pp. 1-11
Author(s):  
Holger Fritzsche ◽  
Elmer Jeto Gomes Ataide ◽  
Axel Boese ◽  
Michael Friebe
Keyword(s):  
Patient Safety ◽  
Irrigation System ◽  
Removal Rate ◽  
Bubble Formation ◽  
Technical Solution ◽  
Air Bubbles ◽  
Gas Bubble ◽  
Suction System ◽  
Gas Formation ◽  
Controlled Irrigation

TURBT (transurethral resection of bladder tumor) is a standard treatment for bladder cancer. Gas bubble formation is caused by the heating of the RF-electrode from the resectoscope, which causes visual impairments and can also lead to explosive gas formation. The purpose of this work is to find a proper technical solution for removing the air bubbles and toxic gases during electro-resection thereby providing patient safety as well as better operating comfort for surgeons. A continuously controlled irrigation system and catheter based simultaneous suction system was designed, implemented and tested, with an average removal rate of 70% of the air bubbles and gases that appeared inside the urinary bladder. The setup was tested using a dedicated phantom.

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