scholarly journals Gulf of Alaska ice-marginal lake area change over the Landsat record and potential physical controls

2021 ◽  
Vol 15 (7) ◽  
pp. 3255-3278
Author(s):  
Hannah R. Field ◽  
William H. Armstrong ◽  
Matthias Huss
Keyword(s):  
Mass Loss ◽  
Flood Hazard ◽  
Gulf Of Alaska ◽  
High Elevation ◽  
Statistical Investigation ◽  
Lake Area ◽  
Area Change ◽  
Positive Feedbacks ◽  
Proglacial Lakes ◽  
Physical Controls

Abstract. Lakes in contact with glacier margins can impact glacier evolution as well as the downstream biophysical systems, flood hazard, and water resources. Recent work suggests positive feedbacks between glacier wastage and ice-marginal lake evolution, although precise physical controls are not well understood. Here, we quantify ice-marginal lake area change in understudied northwestern North America from 1984–2018 and investigate climatic, topographic, and glaciological influences on lake area change. We delineate time series of sampled lake perimeters (n=107 lakes) and find that regional lake area has increased 58 % in aggregate, with individual proglacial lakes growing by 1.28 km2 (125 %) and ice-dammed lakes shrinking by 0.04 km2 (−15 %) on average. A statistical investigation of climate reanalysis data suggests that changes in summer temperature and winter precipitation exert minimal direct influence on lake area change. Utilizing existing datasets of observed and modeled glacial characteristics, we find that large, wide glaciers with thick lake-adjacent ice are associated with the fastest rate of lake area change, particularly where they have been undergoing rapid mass loss in recent times. We observe a dichotomy in which large, low-elevation coastal proglacial lakes have changed most in absolute terms, while small, interior lakes at high elevation have changed most in relative terms. Generally, the fastest-changing lakes have not experienced the most dramatic temperature or precipitation change, nor are they associated with the highest rates of glacier mass loss. Our work suggests that, while climatic and glaciological factors must play some role in determining lake area change, the influence of a lake's specific geometry and topographic setting overrides these external controls.

scholarly journals Topography exerts primary control on the rate of Gulf of Alaska ice-marginal lake area change over the Landsat record

2021 ◽  
Author(s):  
Hannah R. Field ◽  
William H. Armstrong ◽  
Matthias Huss
Keyword(s):  
Mass Loss ◽  
Flood Hazard ◽  
Gulf Of Alaska ◽  
High Elevation ◽  
Winter Precipitation ◽  
Statistical Investigation ◽  
Lake Area ◽  
Primary Control ◽  
Area Change ◽  
Proglacial Lakes

Abstract. Lakes in contact with glacier margins can impact glacier evolution as well as the downstream biophysical systems, flood hazard, and water resources. Recent work indicates that glacier wastage influences ice-marginal lake evolution, although precise physical controls are not well understood. Here, we quantify ice-marginal lake area change in understudied northwestern North America from 1984–2018 and investigate climatic, topographic, and glaciological influences on lake area change. We delineate timeseries of sampled lake (n = 107) perimeters and find that regional lake area has increased 58 % in aggregate, with individual proglacial lakes growing by 3.08 km2 and ice-dammed lakes shrinking by 0.88 km2 on average. A statistical investigation of climate reanalysis data suggests that changes in summer temperature and winter precipitation exert minimal direct influence on lake area change. Utilizing existing datasets of observed and modelled glacial characteristics, we find that large, wide glaciers with thick lake-adjacent ice are associated with the fastest rate of lake area change, particularly where they are undergoing rapid mass loss in recent times. We observe a dichotomy in which large, low-elevation coastal proglacial lakes have changed most in absolute terms, while small, interior lakes at high elevation changed most in relative terms. These systems have not experienced the most dramatic temperature or precipitation change, nor are they associated with the highest rates of glacier mass loss. Our work suggests that, while climatic and glaciological factors must play some role in determining lake area change, the influence of a lake's specific geometry and topographic setting overrides these external controls.

scholarly journals Glacier mass and area changes on the Kenai Peninsula, Alaska, 1986–2016

2020 ◽  
Vol 66 (258) ◽  
pp. 603-617 ◽  
Author(s):  
Ruitang Yang ◽  
Regine Hock ◽  
Shichang Kang ◽  
Donghui Shangguan ◽  
Wanqin Guo
Keyword(s):  
Mass Loss ◽  
Fresh Water ◽  
Thermal Emission ◽  
Gulf Of Alaska ◽  
High Elevation ◽  
Kenai Peninsula ◽  
South Central ◽  
Digital Elevation ◽  
Global Sea Level ◽  
Elevation Model

AbstractGlacier mass loss in Alaska has implications for global sea level rise, fresh water input into the Gulf of Alaska and terrestrial fresh water resources. We map all glaciers (>4000 km2) on the Kenai Peninsula, south central Alaska, for the years 1986, 1995, 2005 and 2016, using satellite images. Changes in surface elevation and volume are determined by differencing a digital elevation model (DEM) derived from Advanced Spaceborne Thermal Emission and Reflection Radiometer stereo images in 2005 from the Interferometric Synthetic Aperture Radar DEM of 2014. The glacier area shrunk by 543 ± 123 km2 (12 ± 3%) between 1986 and 2016. The region-wide mass-balance rate between 2005 and 2014 was −0.94 ± 0.12 m w.e. a−1 (−3.84 ± 0.50 Gt a−1), which is almost twice as negative than found for earlier periods in previous studies indicating an acceleration in glacier mass loss in this region. Area-averaged mass changes were most negative for lake-terminating glaciers (−1.37 ± 0.13 m w.e. a−1), followed by land-terminating glaciers (−1.02 ± 0.13 m w.e. a−1) and tidewater glaciers (−0.45 ± 0.14 m w.e. a−1). Unambiguous attribution of the observed acceleration in mass loss over the last decades is hampered by the scarcity of observational data, especially at high elevation, and by large interannual variability.

Effect of Sample Width on Downward Flame Spread over Typical Energy Conservation Material at a High Elevation Area

2014 ◽  
Vol 664 ◽  
pp. 199-203 ◽  
Author(s):  
Wei Guang An ◽  
Lin Jiang ◽  
Jin Hua Sun ◽  
K.M. Liew
Keyword(s):  
Mass Loss ◽  
Flame Spread ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
High Elevation ◽  
Flame Height ◽  
Spread Rate ◽  
Flame Spread Rate ◽  
Sample Width ◽  
Downward Flame Spread

An experimental study on downward flame spread over extruded polystyrene (XPS) foam at a high elevation is presented. The flame shape, flame height, mass loss rate and flame spread rate were measured. The influences of width and high altitude were investigated. The flame fronts are approximately horizontal. Both the intensity of flame pulsation and the average flame height increase with the rise of sample width. The flame spread rate first drops and then rises with an increase in width. The average flame height, mass loss rate and flame spread rate at the higher elevation is smaller than that at a low elevation, which demonstrates that the XPS fire risk at the higher elevation area is lower. The experimental results agree well with the theoretical analysis. This work is vital to the fire safety design of building energy conservation system.

Glacier retreat and climate change: Documenting the last 50 years of Alpine glacier history from area and geometry changes of Dosdè Piazzi glaciers (Lombardy Alps, Italy)

2011 ◽  
Vol 35 (2) ◽  
pp. 161-182 ◽  
Author(s):  
Guglielmina Adele Diolaiuti ◽  
Davide Maragno ◽  
Carlo D'Agata ◽  
Claudio Smiraglia ◽  
Daniele Bocchiola
Keyword(s):  
Time Window ◽  
Rock Outcrops ◽  
Area Change ◽  
Positive Feedbacks ◽  
Aerial Photos ◽  
Alpine Glacier ◽  
Mountain Glaciers ◽  
Area Reduction ◽  
Low Latitudes ◽  
Collapse Structures

The recent rapid mass loss of mountain glaciers in response to climate warming has been reported for high and low latitudes all over the Earth. The paper analyses and discusses the recent evolution of a representative glacierized group within the Italian Alps, the Piazzi—Dosdè, where small glaciers are experiencing considerable retreat and shrinking. We analysed aerial photos to calculate area and geometry changes in the time window 1954—2003, and glaciological and geomorphological surveys were also performed. The estimated area change during 1954—2003 was —3.97 km2 (—51% of the area coverage in 1954). Area reduction increased more recently: area change during 1991—2003 (12 years) was —1.74 km2, against —0.67 km2 during 1981—1991 (10 years), and —1.57 km 2 during 1954—1981 (27 years). Moreover, analysis of the most recent orthophotos acquired during the summer of 2003 under exceptional conditions (i.e. total absence of snow cover) allowed observation and mapping of changes affecting glacier shape and morphology, including growing rock outcrops, tongue separations, formation of proglacial lakes, increasing supraglacial debris and collapse structures. Such processes cause positive feedbacks that accelerate further glacier disintegration once they appear. From a geodynamical perspective, the Dosdè Piazzi is now experiencing transition from a glacial system to a paraglacial one; areas where in the past the shaping and driving factors were glaciers are now subject to the action of melting water, slope evolution and periglacial processes.

scholarly journals Growth of a high-elevation large inland lake, associated with climate change and permafrost degradation in Tibet

2010 ◽  
Vol 14 (3) ◽  
pp. 481-489 ◽  
Author(s):  
J. Liu ◽  
S. Kang ◽  
T. Gong ◽  
A. Lu
Keyword(s):  
High Elevation ◽  
Annual Runoff ◽  
Annual Precipitation ◽  
The Tibetan Plateau ◽  
Permafrost Degradation ◽  
Lake Area ◽  
Pan Evaporation ◽  
Precipitation Increase ◽  
Nam Co Lake

Abstract. This study analyzed satellite images and long term climate variables from a high-elevation meteorological station (4730 m) and streamflow records to examine hydrological response of Nam Co Lake (4718 m), the largest lake on the Tibetan Plateau, over the last 50 years. The results show the lake area extended by 51.8 km2 (2.7% of the total area) when compared with the area in 1976. This change is associated with an annual precipitation increase of 65 mm (18.6%), annual and winter mean temperature increases of 0.9 °C and 2.1 °C respectively, an annual runoff increase of 20% and an annual pan evaporation decrease of about 2%, during the past 20 years. The year of the change point in annual precipitation, air temperature, annual pan evaporation and runoff occurred in 1971, 1983, 1997 and 1997, respectively. The timing of the lake growth corresponds with the abrupt increase in annual precipitation and runoff since the mid-1990s.

scholarly journals Greenland high-elevation mass balance: inference and implication of reference period (1961–90) imbalance

2015 ◽  
Vol 56 (70) ◽  
pp. 105-117 ◽  
Author(s):  
William Colgan ◽  
Jason E. Box ◽  
Morten L. Andersen ◽  
Xavier Fettweis ◽  
Beáta Csathó ◽  
...  
Keyword(s):  
Mass Loss ◽  
Mass Balance ◽  
Greenland Ice Sheet ◽  
Mass Gain ◽  
High Elevation ◽  
Reference Period ◽  
Input Output ◽  
Specific Mass ◽  
Ice Dynamics ◽  
Dynamic Mass

AbstractWe revisit the input–output mass budget of the high-elevation region of the Greenland ice sheet evaluated by the Program for Arctic Regional Climate Assessment (PARCA). Our revised reference period (1961–90) mass balance of 54±48 Gt a–1 is substantially greater than the 0±21 Gt a–1 assessed by PARCA, but consistent with a recent, fully independent, input–output estimate of high-elevation mass balance (41±61 Gt a–1). Together these estimates infer a reference period high-elevation specific mass balance of 4.8±5.4 cm w.e. a–1. The probability density function (PDF) associated with this combined input–output estimate infers an 81% likelihood of high-elevation specific mass balance being positive (>0 cm w.e. a–1) during the reference period, and a 70% likelihood that specific balance was >2 cm w.e. a–1. Given that reference period accumulation is characteristic of centurial and millennial means, and that in situ mass-balance observations exhibit a dependence on surface slope rather than surface mass balance, we suggest that millennial-scale ice dynamics are the primary driver of subtle reference period high-elevation mass gain. Failure to acknowledge subtle reference period dynamic mass gain can result in underestimating recent dynamic mass loss by ~17%, and recent total Greenland mass loss by ~7%.

scholarly journals The 25–27 May 2005 Mount Logan Storm. Part I: Observations and Synoptic Overview

2007 ◽  
Vol 8 (3) ◽  
pp. 590-606 ◽  
Author(s):  
G. W. K. Moore ◽  
Gerald Holdsworth
Keyword(s):  
Water Vapor ◽  
Ice Cores ◽  
Gulf Of Alaska ◽  
High Elevation ◽  
Extratropical Cyclone ◽  
Water Vapor Transport ◽  
Climate Signal ◽  
Cold Temperatures ◽  
Budget Analysis ◽  
Weather Stations

Abstract In late May 2005, three climbers were immobilized at 5400 m on Mount Logan, Canada’s highest mountain, by the high-impact weather associated with an extratropical cyclone over the Gulf of Alaska. Rescue operations were hindered by the high winds, cold temperatures, and heavy snowfall associated with the storm. Ultimately, the climbers were rescued after the weather cleared. Just prior to the storm, two automated weather stations had been deployed on the mountain as part of a research program aimed at interpreting the climate signal contained in summit ice cores. These data provide a unique and hitherto unobtainable record of the high-elevation meteorological conditions associated with an intense extratropical cyclone. In this paper, data from these weather stations along with surface and sounding data from the nearby town of Yakutat, Alaska, satellite imagery, and the NCEP reanalysis are used to characterize the synoptic-scale conditions associated with this storm. Particular emphasis is placed on the water vapor transport associated with this storm. The authors show that during this event, subtropical moisture was transported northward toward the Mount Logan region. The magnitude of this transport into the Gulf of Alaska was exceeded only 1% of the time during the months of May and June over the period 1948–2005. As a result, the magnitude of the precipitable water field in the Gulf of Alaska region attained values usually found in the Tropics. An atmospheric moisture budget analysis indicates that most of the moisture advected into the Mount Logan region was preexisting water vapor already in the subtropical atmosphere and was not water vapor evaporated from the surface during the evolution of the storm. Implications of this moisture source for understanding of the water isotopic climate signal in the Mount Logan ice cores will be discussed.

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