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Статті в журналах з теми "Glacier geometry change"
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O'Neal, Michael A., Brian Hanson, Sebastian Carisio, and Ashley Satinsky. "Detecting recent changes in the areal extent of North Cascades glaciers, USA." Quaternary Research 84, no. 2 (September 2015): 151–58. http://dx.doi.org/10.1016/j.yqres.2015.05.007.
Повний текст джерелаАнотація:
We present an exhaustive spatial analysis using the geographic, geometric, and hypsometric characteristics of 742 North Cascades glaciers to evaluate changes in their areal extents over a half-century period. Our results indicate that, contrary to our initial expectations, glacier change throughout the study region cannot be explained readily by correlations in glacier location, size, or shape. Because of the large error attributable to annual variations in glacier area due to snowpack, no statistically reliable change could be detected for 444 glaciers in our study (a slight majority). Of the North Cascades glaciers that do exhibit detectable change, a majority decreased in area, but nevertheless, some were detectably growing. These findings suggest that the integration of weather patterns over time does not neatly translate into correlations with natural variations in the geometry of glaciers. Our statistical analyses of the changes observed indicate that geometric data from a large number of glaciers, as well as a surprisingly large amount of spatial change, are required for a credible statistical detection of glacier-length and area changes over a short (multidecadal) period of time.
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VEITCH, STEPHEN A., and MEREDITH NETTLES. "Assessment of glacial-earthquake source parameters." Journal of Glaciology 63, no. 241 (October 2017): 867–76. http://dx.doi.org/10.1017/jog.2017.52.
Повний текст джерелаАнотація:
ABSTRACTGlacial earthquakes are slow earthquakes of magnitude M~5 associated with major calving events at near-grounded marine-terminating glaciers. These globally detectable earthquakes provide information on the grounding state of outlet glaciers and the timing of large calving events. Seismic source modeling of glacial earthquakes provides information on the size and orientation of forces associated with calving events. We compare force orientations estimated using a centroid-single-force technique with the calving-front orientations of the source glaciers at or near the time of earthquake occurrence. We consider earthquakes recorded at four glaciers in Greenland – Kangerdlugssuaq Glacier, Helheim Glacier, Kong Oscar Glacier, and Jakobshavn Isbræ – between 1999 and 2010. We find that the estimated earthquake force orientations accurately represent the orientation of the calving front at the time of the earthquake, and that seismogenic calving events are produced by a preferred section of the calving front, which may change with time. We also find that estimated earthquake locations vary in a manner consistent with changes in calving-front position, though with large scatter. We conclude that changes in glacial-earthquake source parameters reflect true changes in the geometry of the source glaciers, providing a means for identifying changes in glacier geometry and dynamics that complements traditional remote-sensing techniques.
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Paul, F. "The influence of changes in glacier extent and surface elevation on modeled mass balance." Cryosphere 4, no. 4 (December 10, 2010): 569–81. http://dx.doi.org/10.5194/tc-4-569-2010.
Повний текст джерелаАнотація:
Abstract. Glaciers are widely recognized as unique demonstration objects for climate change impacts, mostly due to the strong change of glacier length in response to small climatic changes. However, glacier mass balance as the direct response to the annual atmospheric conditions can be better interpreted in meteorological terms. When the climatic signal is deduced from long-term mass balance data, changes in glacier geometry (i.e. surface extent and elevation) must be considered as such adjustments form an essential part of the glacier reaction to new climatic conditions. In this study, a set of modelling experiments is performed to assess the influence of changes in glacier geometry on mass balance for constant climatic conditions. The calculations are based on a simplified distributed energy/mass balance model in combination with information on glacier extent and surface elevation for the years 1850 and 1973/1985 for about 60 glaciers in the Swiss Alps. The results reveal that over this period about 50–70% of the glacier reaction to climate change (here a one degree increase in temperature) is "hidden" in the geometric adjustment, while only 30–50% can be measured as the long-term mean mass balance. For larger glaciers, the effect of the areal change is partly reduced by a lowered surface elevation, which results in a slightly more negative balance despite a potential increase of topographic shading. In view of several additional reinforcement feedbacks that are observed in periods of strong glacier decline, it seems that the climatic interpretation of long-term mass balance data is rather complex.
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Paul, F. "The influence of changes in glacier extent and surface elevation on modeled mass balance." Cryosphere Discussions 4, no. 2 (June 16, 2010): 737–66. http://dx.doi.org/10.5194/tcd-4-737-2010.
Повний текст джерелаАнотація:
Abstract. Glaciers are widely recognized as unique demonstration objects for climate change impacts, mostly due to the strong change of glacier length in response to small climatic changes. However, glacier mass balance as the direct response to the annual atmospheric conditions can be better interpreted in meteorological terms. When the climatic signal is deduced from long-term mass balance data, changes in glacier geometry (i.e. surface extent and elevation) must be considered as such adjustments form an essential part of the glacier reaction to new climatic conditions. In this study, a set of modeling experiments is performed to assess the influence of changes in glacier geometry on mass balance for constant climatic conditions. The calculations are based on a simplified distributed energy/mass balance model in combination with information on glacier extent and surface elevation for the years 1850 and 1973/1985 for a larger sample of glaciers in the Swiss Alps. The results reveal that about 50–70% of the glacier reaction to climate change (here a one degree increase in temperature) is "hidden" in the geometric adjustment, while only 30–50% can be measured as the long-term mean mass balance. Thereby, changes in glacier extent alone have an even stronger effect, but they are partly compensated for by a lowered surface elevation which gives on average a slightly more negative balance despite an increase of topographic shading. In view of several additional reinforcement feedbacks that are observed in periods of strong glacier decline, it seems that the climatic interpretation of mass balance data is also rather complex.
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Brugger, Keith A. "Non-Synchronous Response Of Rabots Glaciar and Storglaciaren To Recent Climatic Change." Annals of Glaciology 14 (1990): 331–32. http://dx.doi.org/10.3189/s0260305500008910.
Повний текст джерелаАнотація:
Rabots glaciär and Storglaciären are small valley glaciers located in the Kebnekaise massif of northern Sweden. Rabots glaciär flows west from the summit of Kebnekaise (2114 m) and Storglaciären flows east; thus regional climate affecting the glaciers is the same. The glaciers are of comparable size and geometry, although differences exist in the variation of ice thickness and the subglacial bedrock topography within the respective basins. The thickness of Rabots glaciär appears to be relatively uniform over much of its length and its bed smooth. The bed over which Storglaciären flows is characterized by a “riegel and basin” topography and ice thicknesses vary accordingly.Advance and retreat of the glaciers during the last 100 years has been documented by historical records and photographs, measurements of ice retreats, and detailed glacial and geological studies. Both advanced to their maximum 20th century extents around 1916. In their subsequent retreat, Rabots glaciär has lagged behind Storglaciären by 10 years.Mass-balance studies for the years 1981–87 suggest that while the “local” climate for each glacier is slightly different (in terms of the magnitude of acumulation and ablation), variations in local climate are synchronous. Non-synchronous response of the glaciers is therefore attributed to differences in glacier dynamics, which are quite apparent when velocity profiles are compared. Ice velocities on Rabots glaciär vary little from an average of −7.5 m/yr, resulting in a longitudinal strain rate, r, of about 6 × 10−3yr −1. In contrast, values for r on Storglaciären are as high as 2.5 × 10−2 yr−1 owing to greater ice velocities and variation in ice velocity. Since the response time of a glacier is proportional to 1/r, the lower strain rates found on Rabots glaciär probably account for its more sluggish retreat.A simple, non-diffusive, kinematic wave model is used to analyze the response of the glaciers to a step-like perturbation in mass balance. This model predicts that the response time of Storglaciären is on the order of 30 years and that a new steady-state profile would be attained in about 50 years. The predicted response time of Rabots glaciär is about 75 years, its new steady-state profile being reached after more than 100 years.More accurate analyses of each glacier's response to climatic change use a time-dependent numerical model which includes the effects of diffusion. The climatic forcing in these modelling efforts is represented by the changes in mass balance resulting from changes in the equilibrium line altitude (ELA). ELAs can be correlated to regional meteorological variables which in turn are used to create a “synthetic” record of ELA variations where necessary. Therefore climatic oscillations since the turn of the century can be simulated by the appropriate changes in ELA. Using synchronous variations of ELAs and their 1916 profiles as datum states, the modeled behavior of Rabots glaciär and Storglaciären shows that: (a) the rates of ice retreat for each glacier are in reasonable agreement with those observed; and (b) Rabots glaciär took slightly longer than Storglaciären to react to the slight warming that occurred shortly after their 1916 advance.
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Brugger, Keith A. "Non-Synchronous Response Of Rabots Glaciar and Storglaciaren To Recent Climatic Change." Annals of Glaciology 14 (1990): 331–32. http://dx.doi.org/10.1017/s0260305500008910.
Повний текст джерелаАнотація:
Rabots glaciär and Storglaciären are small valley glaciers located in the Kebnekaise massif of northern Sweden. Rabots glaciär flows west from the summit of Kebnekaise (2114 m) and Storglaciären flows east; thus regional climate affecting the glaciers is the same. The glaciers are of comparable size and geometry, although differences exist in the variation of ice thickness and the subglacial bedrock topography within the respective basins. The thickness of Rabots glaciär appears to be relatively uniform over much of its length and its bed smooth. The bed over which Storglaciären flows is characterized by a “riegel and basin” topography and ice thicknesses vary accordingly. Advance and retreat of the glaciers during the last 100 years has been documented by historical records and photographs, measurements of ice retreats, and detailed glacial and geological studies. Both advanced to their maximum 20th century extents around 1916. In their subsequent retreat, Rabots glaciär has lagged behind Storglaciären by 10 years. Mass-balance studies for the years 1981–87 suggest that while the “local” climate for each glacier is slightly different (in terms of the magnitude of acumulation and ablation), variations in local climate are synchronous. Non-synchronous response of the glaciers is therefore attributed to differences in glacier dynamics, which are quite apparent when velocity profiles are compared. Ice velocities on Rabots glaciär vary little from an average of −7.5 m/yr, resulting in a longitudinal strain rate, r, of about 6 × 10−3yr −1. In contrast, values for r on Storglaciären are as high as 2.5 × 10−2 yr−1 owing to greater ice velocities and variation in ice velocity. Since the response time of a glacier is proportional to 1/r, the lower strain rates found on Rabots glaciär probably account for its more sluggish retreat. A simple, non-diffusive, kinematic wave model is used to analyze the response of the glaciers to a step-like perturbation in mass balance. This model predicts that the response time of Storglaciären is on the order of 30 years and that a new steady-state profile would be attained in about 50 years. The predicted response time of Rabots glaciär is about 75 years, its new steady-state profile being reached after more than 100 years. More accurate analyses of each glacier's response to climatic change use a time-dependent numerical model which includes the effects of diffusion. The climatic forcing in these modelling efforts is represented by the changes in mass balance resulting from changes in the equilibrium line altitude (ELA). ELAs can be correlated to regional meteorological variables which in turn are used to create a “synthetic” record of ELA variations where necessary. Therefore climatic oscillations since the turn of the century can be simulated by the appropriate changes in ELA. Using synchronous variations of ELAs and their 1916 profiles as datum states, the modeled behavior of Rabots glaciär and Storglaciären shows that: (a) the rates of ice retreat for each glacier are in reasonable agreement with those observed; and (b) Rabots glaciär took slightly longer than Storglaciären to react to the slight warming that occurred shortly after their 1916 advance.
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Sutherland, D. A., R. H. Jackson, C. Kienholz, J. M. Amundson, W. P. Dryer, D. Duncan, E. F. Eidam, R. J. Motyka, and J. D. Nash. "Direct observations of submarine melt and subsurface geometry at a tidewater glacier." Science 365, no. 6451 (July 25, 2019): 369–74. http://dx.doi.org/10.1126/science.aax3528.
Повний текст джерелаАнотація:
Ice loss from the world’s glaciers and ice sheets contributes to sea level rise, influences ocean circulation, and affects ecosystem productivity. Ongoing changes in glaciers and ice sheets are driven by submarine melting and iceberg calving from tidewater glacier margins. However, predictions of glacier change largely rest on unconstrained theory for submarine melting. Here, we use repeat multibeam sonar surveys to image a subsurface tidewater glacier face and document a time-variable, three-dimensional geometry linked to melting and calving patterns. Submarine melt rates are high across the entire ice face over both seasons surveyed and increase from spring to summer. The observed melt rates are up to two orders of magnitude greater than predicted by theory, challenging current simulations of ice loss from tidewater glaciers.
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Roe, Gerard H., and Michael A. O’Neal. "The response of glaciers to intrinsic climate variability: observations and models of late-Holocene variations in the Pacific Northwest." Journal of Glaciology 55, no. 193 (2009): 839–54. http://dx.doi.org/10.3189/002214309790152438.
Повний текст джерелаАнотація:
AbstractDiscriminating between glacier variations due to natural climate variability and those due to true climate change is crucial for the interpretation and attribution of past glacier changes, and for the expectations of future changes. We explore this issue for the well-documented glaciers of Mount Baker in the Cascades Mountains of Washington State, USA, using glacier histories, glacier modeling, weather data and numerical weather model output. We find that natural variability alone is capable of producing kilometer-scale excursions in glacier length on multi-decadal and centennial timescales. Such changes are similar in magnitude to those attributed to a global Little Ice Age. The null hypothesis, that no climate change is required to explain the glacier fluctuations in this setting, cannot be rejected. These results for Mount Baker glaciers are also consistent with an earlier study analyzing individual glaciers in Scandinavia and the Alps. The principle that long-timescale fluctuations of glacier length can be driven by short-timescale fluctuations in climate reflects a robust and fundamental property of stochastically forced physical systems with memory. It is very likely that this principle also applies to other Alpine glaciers and that it therefore complicates interpretations of the relationship between glacier and climate history. However, the amplitude and timescale of the length fluctuations depends on the details of the particular glacier geometry and climatic setting, and this remains largely unevaluated for most glaciers.
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Winsvold, S. H., L. M. Andreassen, and C. Kienholz. "Glacier area and length changes in Norway from repeat inventories." Cryosphere 8, no. 5 (October 20, 2014): 1885–903. http://dx.doi.org/10.5194/tc-8-1885-2014.
Повний текст джерелаАнотація:
Abstract. In this study, we assess glacier area and length changes in mainland Norway from repeat Landsat TM/ETM+-derived inventories and digitized topographic maps. The multi-temporal glacier inventory consists of glacier outlines from three time ranges: 1947 to 1985 (GIn50), 1988 to 1997 (GI1990), and 1999 to 2006 (GI2000). For the northernmost regions, we include an additional inventory (GI1900) based on historic maps surveyed between 1895 and 1907. Area and length changes are assessed per glacier unit, 36 subregions, and for three main parts of Norway: southern, central, and northern. The results show a decrease in the glacierized area from 2994 km2 in GIn50 to 2668 km2 in GI2000 (total 2722 glacier units), corresponding to an area reduction of −326 km2, or −11% of the initial GIn50 area. The average length change for the full epoch (within GIn50 and GI2000) is −240 m. Overall, the comparison reveals both area and length reductions as general patterns, even though some glaciers have advanced. The three northernmost subregions show the highest retreat rates, whereas the central part of Norway shows the lowest change rates. Glacier area and length changes indicate that glaciers in maritime areas in southern Norway have retreated more than glaciers in the interior, and glaciers in the north have retreated more than southern glaciers. These observed spatial trends in glacier change are related to a combination of several factors such as glacier geometry, elevation, and continentality, especially in southern Norway.
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Winsvold, S. H., L. M. Andreassen, and C. Kienholz. "Glacier area and length changes in Norway from repeat inventories." Cryosphere Discussions 8, no. 3 (June 10, 2014): 3069–115. http://dx.doi.org/10.5194/tcd-8-3069-2014.
Повний текст джерелаАнотація:
Abstract. In this study, we assess glacier area and length changes in mainland Norway from repeat Landsat TM/ETM+ derived inventories and digitized topographic maps. The multi-temporal glacier inventory consists of glacier outlines from within three time ranges: 1947 to 1985 (GIn50), 1988 to 1997 (GI1990), and 1999 to 2006 (GI2000). For the northernmost regions, we include an additional inventory (GI1900), based on historic maps surveyed between 1895 to 1907. Area and length changes are assessed per glacier unit, for 36 subregions, and for three main parts of Norway: southern, central and northern Norway. The results show a decrease of the glacierized area from 2994 km2 in GIn50, to 2668 km2 in GI2000 (totally 2722 glacier units), corresponding to an area reduction of −326 km2, or −11% of the initial GIn50 area. This is equivalent to an average change rate of −11 km2 a−1 over the past 30 years. The average length change for the full epoch (within GIn50 and GI2000) is −240 m, corresponding to an average length change rate of −8 m a−1. Overall, the comparison reveals both area and length reduction as a general pattern, even though some glaciers have advanced. The three northernmost glacier regions show the strongest retreat rates, whereas the central part of Norway shows the lowest change rates. Glacier area and length changes indicate that glaciers in maritime areas in southern Norway have retreated more than glaciers in the interior, and glaciers in the north have retreated more than southern glaciers. These observed spatial trends in glacier change are related to a combination of several geographical factors like glacier geometry and elevation, and other climatic aspects, such as continentality and the North Atlantic Oscillation.
Дисертації з теми "Glacier geometry change"
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Florentine, Caitlyn Elizabeth. "Understanding Changes to Glacier and Ice Sheet Geometry| The Roles of Climate and Ice Dynamics." Thesis, University of Montana, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10934265.
Повний текст джерелаАнотація:
Glacier and ice sheet geometry depend on climatic and ice dynamic processes that are coupled and often highly complex. Thus, partitioning and understanding the drivers of change to glacier and ice sheet geometry requires creative approaches.
Radiostratigraphy data document emergent layers in the ablation zone of western Greenland that emulate theoretical englacial flow paths. Yet true alignment between radar layers and the englacial flow field can be uncertain because these structures have travelled hundreds of km from their original point of deposition, have been shaped by ice deformation for millennia, and have been subjected to complex and three-dimensional ice motion across steep and rugged bedrock terrain. In Chapter 2 I address this problem. Using ice dynamics information from a thermomechanically coupled, higher order ice sheet model, in conjunction with an observationally based test built on principles of mass conservation, I demonstrate that real world effects do not disrupt alignment between targeted ablation zone emergent radar layers and the local, present-day ice flow field.
Topographically driven processes such as wind-drifting, avalanching, and shading, can sustain mountain glaciers situated in settings that are otherwise unsuitable for maintaining glacier ice. Local topography can thus disrupt the way regional climate controls glacier retreat, which limits insight into the climate representativeness of some mountain glaciers. In Chapters 3 and 4 I address this issue. Analyzing glaciological, geodetic, and meteorological data, I quantitatively demonstrate that the glacier-climate relationship at a retreating cirque glacier evolved as mass balance processes associated with local topography became more influential from 1950 to 2014. I then assess regional glacier area changes in the Northern Rockies from the Little Ice Age glacial maxima to the modern. I characterize terrain parameters at each glacier and estimate glacier thickness. Using these data and extremely simple models of ice mass loss I assess climatic, topographic, and glaciological drivers. Predictable factors like initial glacier size, aspect, and elevation only partly explain the observed pattern of glacier disappearance. This implies that less predictable and poorly resolved processes like avalanching and wind-drifting drive spatially complex patterns of glacier mass change across this mountain landscape.
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Satinsky, Ashley M. "Geometric changes of 742 North Cascade glaciers derived from 1958 and 2006 aerial imagery." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 69 p, 2009. http://proquest.umi.com/pqdweb?did=1885544301&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Повний текст джерела
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Tawde, Sayli Atul. "Estimation of Glacier Mass Balance at Basin Scale in the Himalaya for Recent Decades and Future." Thesis, 2018. https://etd.iisc.ac.in/handle/2005/5497.
Повний текст джерелаАнотація:
The Himalayan glaciers are a major source of perennial river systems which support the livelihood of millions of people in south Asia. Therefore, it is important to understand changes in water resources due to changes in glacier-stored water. In order to understand long-term changes in glacier-stored water, mass balance studies at larger spatial scale are needed. Therefore, in this dissertation annual mass balance of glaciers at basin scale in the current and projected future climate is assessed. In this dissertation, for the first time, the long-term investigations of glacier mass balance for a period of 1980s to 2090s in the Chandra basin, western Himalaya are analysed. The mass balance of 146 glaciers in the basin, occupying an area of ~654.29 km2 and the total water volume of ~62.1 ± 16 Gt are analysed. Results of this study suggest that mass loss in the Chandra basin has accelerated from mid-1990‘s to the current decade and could persist till the end of century. Sensitivity analysis suggests that a 20% increase in precipitation can offset changes in mass balance from a 1°C temperature rise. The basin has lost ~19% of its volume during 1984-2013 and the volume loss is ~67% if only the twenty-nine low elevation glaciers are considered.
The ensemble mean of climate models considered in this dissertation project a temperature rise of 2.2- 2.9°C (RCP 4.5, the moderate emission scenario) and 4.3- 6°C (RCP 8.5; the high emission scenario) by 2090‘s near the basin with a steady or decreasing trend in snowfall. In response to the projected climate change, the basin will retain only 40-43% (RCP 4.5) and 29-34% (RCP 8.5) of the current glacier stored water volume stored by the end of century. However, the volume loss is very large (~97% of the present volume) for low altitude
glaciers indicating a need for effective water management strategies in mountain communities in the future. To calculate the annual mass balance of glaciers at larger spatial and temporal scales, the Accumulation Area Ratio (AAR) method is used in this analysis. However, a new approach is proposed to the conventional methods of equilibrium line altitude (ELA) estimation in AAR method. Satellite-derived transient snowlines, in-situ meteorological observations and a snow-melt model are combined to model the position of ELA. When the field estimates are used for validation, the improved AAR method reduces the biases in mass balance estimates by 46% compared to the traditional technique. Results from the improved method are also in the good agreement with the geodetic estimates for recent decades. The possible climate change impacts on glaciers during 21st century are quantified using the improved AAR method and the glacier geometry model driven by climate projections from fine resolution multiple climate models. The projected future values of mass balance, area and volume (along with uncertainties) in the present dissertation are within the range of results from previous studies at different spatial scales and resolutions. Overall, this study highlights the likely severe impacts to water resources in the Himalaya if CO2 emissions follow the high-emission scenario of RCP8.5.
Частини книг з теми "Glacier geometry change"
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"Advances in Understanding Landscape Influences on Freshwater Habitats and Biological Assemblages." In Advances in Understanding Landscape Influences on Freshwater Habitats and Biological Assemblages, edited by Peter C. Jacobson, Gretchen J. A. Hansen, Leif G. Olmanson, Kevin E. Wehrly, Catherine L. Hein, and Lucinda B. Johnson. American Fisheries Society, 2019. http://dx.doi.org/10.47886/9781934874561.ch8.
Повний текст джерелаАнотація:
<i>Abstract.</i>—Freshwater resources are threatened by multiple stressors, and identifying the relative roles of each is necessary for effective management. The relative contributions of eutrophication and climate change to the loss of coldwater fish habitat was estimated for 5,220 stratified lakes in Michigan, Minnesota, and Wisconsin. A hypolimnetic oxygen model was coupled with a landscape disturbance model to estimate change in oxythermal habitat since European settlement. The general additive model predicted late-summer oxythermal habitat conditions as a function of remotely sensed Secchi depth (mean of 1995–2014 values), geometry ratio (area0.25/maximum depth), and mean July air temperature (1995–2014). The use of the remotely sensed water-clarity variable allowed modeling of lakes that do not have in situ water-quality data. The landscape disturbance model predicted remotely sensed water clarity as a function of levels of catchment land-use disturbance, geometry ratio, and proportion of glacial outwash soils in each catchment. Historic coldwater habitat was estimated for undisturbed landscape conditions and an earlier period of climate and then compared to contemporary conditions. Eutrophication and climate change substantially reduced coldwater fish habitat over the past century in many stratified lakes in Minnesota, Wisconsin, and Michigan. The greatest loss of coldwater habitat occurred in lakes with substantial land-use changes in their catchments, primarily in the Great Plains and Eastern Temperate Forests ecoregions. Oxythermal habitat in many other lakes in the Northern Forests ecoregion remained intact, with only modest changes primarily because of warming climate. To maintain coldwater habitat, deep, clear lakes in the forested ecoregions of Minnesota, Wisconsin, and Michigan should receive high priority for catchment protection efforts. Protective catchment land-use measures will be needed for coldwater fish to survive further climate warming.
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Emery, K. O., and David Neev. "Synopsis." In The Destruction of Sodom, Gomorrah, and Jericho. Oxford University Press, 1995. http://dx.doi.org/10.1093/oso/9780195090949.003.0010.
Повний текст джерелаАнотація:
The two large lakes named Samra and Lisan existed in the Dead Sea graben from 350,000 to 120,000B.p. and 60,000 to 12,000B.p. Their sediments tentatively are correlated with the European Riss and Würm glacial epochs. Thick marls are the chief sediments in the deep water north basin. Rocksalt deposition dominated within the troughs of both north and south basins throughout the intervening Riss-Würm Interglacial stage. Lithology of Lisan Formation (Würm) in that basin indicates rapid and extreme fluctuations of level. Eight major climatic cycles are recorded during Würm glaciation when the level fluctuated between -180 m m.s.l. and probably lower than -400 m m.s.l. Rocksalt was deposited within both basins during warm dry phases of the Lisan stage. At the present state of knowledge no specific tectonic or volcanic activities can be tied to these climatic events. The Holocene Period was similar lithologically to that of the Lisan Formation and transition between them was gradual. Primarily the difference between the two was change in relative time span between alternate wet and dry phases. Dry phases of Holocene gradually became longer while wet ones with Dead Sea transgressions became shorter. Tectonic regimes during the first part—the Natufian age to Early Bronze III, 12,000 to 4400 B.P.—seem to have been milder than later ones, end of Early Bronze III to the present. The severe earthquake that destroyed Sodom and Gomorrah in 4350 B.P. was followed by a 300-year long subphase of gradually warming climate that became extremely dry during the latter part of the Intermediate Bronze age. Climatic Wet Phase III began about 3900 B.P. It was the longest, about 800 years, and most intense wet phase of Holocene and it probably was associated with volcanism. No abrupt cultural or demographic changes are known during transition from Epi-Paleolithic or Geometric Kebaran from the last glacial phase of the Pleistocene Period through Natufian to the early part of Holocene Pre-Pottery Neolithic. The reason for this stability is not clear especially because average temperatures of global oceans during the latest Pleistocene glaciation were appreciably lower than those during Early Holocene (Emiliani, 1978).
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Kelly, S. B., and J. M. Cubitt. "Milankovitch Cyclicity In The Stratigraphic Record— A Review." In Computers in Geology - 25 Years of Progress. Oxford University Press, 1994. http://dx.doi.org/10.1093/oso/9780195085938.003.0016.
Повний текст джерелаАнотація:
The Milankovitch or astronomical theory of paleoclimates relates climatic variation to the amount of solar energy available at the Earth's surface. The theory helps explain periodic, climatically related phenomena such as the Pleistocene ice ages. Identification of Milankovitch cyclicity within sediments demonstrates the influence of climate on sedimentation patterns and creates a time frame for the estimation of basin subsidence rates. Spectral analysis of deep sea and ice cores indicates periodic climatic fluctuations during Tertiary and Quaternary times. These fluctuations are strongly cyclical with low frequencies centered at periods around 400 ka and 100 ka together with shorter periodic components of approximately 41 and 21 ka. Lower frequencies reflect eccentricity of the Earth's orbit; 41- and 21-ka components are associated with periodic changes in the tilt of the Earth's axis and the precession of the equinoxes. Astronomically forced glacial eustasy results in distinct stratigraphic units or parasequences of widespread extent. Milankovitch band parasequences occur in both carbonate and clastic shelf systems, including cyclothemic Upper Paleozoic successions of North America. During the 1920's and 30's the Serbian mathematician Milutin Milankovitch studied cyclical variations in three elements of the Earth-Sun geometry: eccentricity, precession, and obliquity, and was able to calculate the Earth's solar radiation history for the past 650 ka (Milankovitch, 1969). Berger (1978, 1980) accurately determined the periodicities of the three orbital variations. Eccentricity—The Earth's orbit around the Sun is an ellipse; this results in the seasons. The eccentricity of the Earth's orbit periodically departs further from a circle and then reverts to almost true circularity. Periodicities are located around 413, 95, 123, and 100 ka. Secondary peaks appear to be located around 50 and 53 ka. There are further important periodicities at 1.23, 2.04, and 3.4 ma (Schwarzacher, 1991). Precession—Precession refers to variation in time of year at which the Earth is nearest the Sun (perihelion). This variation is caused by the Earth wobbling like a top and swiveling on its axis. Periodicities of 23,000, 22,400, 18,980, and 19,610 yr are recognized and often simplified to two periods of 19 and 23 ka. Secondary peaks are also located around 30 and 15 ka.
Тези доповідей конференцій з теми "Glacier geometry change"
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Juzwa, Nina, Tomasz Konior, and Jakub Świerzawski. "Architecture on the Edge of a City." In 13th International Conference on Applied Human Factors and Ergonomics (AHFE 2022). AHFE International, 2022. http://dx.doi.org/10.54941/ahfe1002334.
Повний текст джерелаАнотація:
The topic concerns the revitalization of a place by the introduction of a new building whose functionality and architectural uniqueness renew and/or develop the place. To put the problem in a broader perspective - the introduction of a building with a non-threatening function and an attractive form makes a declining or stagnant place suddenly appealing again. This applies to both, the built and natural environment. The restauration of both often requires similar revitalization activities and supporting elements.The presented issue is a part of a broader study that concerns architecture as the fine art of building, covering the topic of sustainability in architectural and urban design. The so-called “human factor” is an essential element for shaping a place. It is an element of urban and architectural design of new places. By creating new and different workplaces in declining or stagnant districts, also by introducing unusual architectural forms or materiality, a place can become attractive to users. Previously declining built or natural environment - suddenly become a desirable, growing place. Contemporary international research conducted by neuroscientists confirms the importance of the desire for beauty in ones surroundings. Thus, architectural beauty becomes a vital and economically significant factor in the shaping of the built and natural environment.Present processes of revitalization are usually supported by emphasising elements that make up the “human factor”. It involves balancing the functionality and beauty of an object as important in creating a PLACE in architecture.The topic is presented on the example of architecture of the following buildings:-Gymnasium and Cultural Center in Białołęka, 2006 is located on the edge between urban and landscape areas, on the right bank of the Vistula escarpment. The architectural form reflects the natural landscape. Traditional materiality blends with the context nearly perfectly. -The small buildings of the Cultural Center, 2013, on the outskirts of Warsaw, create a contrast of geometry and materiality to the high-rise blocks of flats. In its shape and material there is a longing for tradition expressed in a balanced, non-intrusive way.-The Krzysztof Kieślowski Film School in Katowice, 2017. The university building for artistic education was tasked to create a PLACE in a declining district. It impresses with its simplicity and its materiality of the traditional material – brick that is presented in a new, changed form. - Stone Pavilion Golędzinow, 2020 is a small building that tells Warsaw residents about nature conservation. The buildings form was created in the image of a post-glacial fossil. It is an object which shape and materiality seems as if taken directly from the natural world. - Press Glass offices in Konopiska, 2021, built in an unexpected place for this type of building. It is located in a former wasteland which was turned into a golf course. The building is intended to promote the excellence of glass - it reflects the green surroundings, and its form builds the uniqueness and beauty of architecture.The co-author of this publication is the designer of the first and fifth example.