scholarly journals InSAR-based characterization of rock glacier movement in the Uinta Mountains, Utah, USA

2021 ◽  
Vol 15 (10) ◽  
pp. 4823-4844
Author(s):  
George Brencher ◽  
Alexander L. Handwerger ◽  
Jeffrey S. Munroe
Keyword(s):  
Snow Water Equivalent ◽  
Late Summer ◽  
Rock Glacier ◽  
Mean Velocity ◽  
Uinta Mountains ◽  
Mountain Environments ◽  
Prominent Component ◽  
Snow Water ◽  
Rock Glaciers ◽  
Climatic Drivers

Abstract. Rock glaciers are a prominent component of many alpine landscapes and constitute a significant water resource in some arid mountain environments. Here, we employ satellite-based interferometric synthetic aperture radar (InSAR) between 2016 and 2019 to identify and monitor active and transitional rock glaciers in the Uinta Mountains (Utah, USA), an area of ∼3000 km2. We used mean velocity maps to generate an inventory for the Uinta Mountains containing 205 active and transitional rock glaciers. These rock glaciers are 11.9 ha in area on average and located at a mean elevation of 3308 m, where mean annual air temperature is −0.25 ∘C. The mean downslope velocity for the inventory is 1.94 cm yr−1, but individual rock glaciers have velocities ranging from 0.35 to 6.04 cm yr−1. To search for relationships with climatic drivers, we investigated the time-dependent motion of three rock glaciers. We found that rock glacier motion has a significant seasonal component, with rates that are more than 5 times faster during the late summer compared to the rest of the year. Rock glacier velocities also appear to be correlated with the snow water equivalent of the previous winter's snowpack. Our results demonstrate the ability to use satellite InSAR to monitor rock glaciers over large areas and provide insight into the environmental factors that control their kinematics.

scholarly journals InSAR-based characterization of rock glacier movement in the Uinta Mountains, Utah, USA

2020 ◽  
Author(s):  
George Brencher ◽  
Alexander L. Handwerger ◽  
Jeffrey S. Munroe
Keyword(s):  
Snow Water Equivalent ◽  
Late Summer ◽  
Rock Glacier ◽  
Mean Velocity ◽  
Uinta Mountains ◽  
Mountain Environments ◽  
Prominent Component ◽  
Snow Water ◽  
Rock Glaciers ◽  
Climatic Drivers

Abstract. Rock glaciers are a prominent component of many alpine landscapes and constitute a significant water resource in some arid mountain environments. Here, we employ satellite-based interferometric synthetic aperture radar (InSAR) to identify and monitor active rock glaciers in the Uinta Mountains (Utah, USA), an area of ~10,000 km2. We used mean velocity maps to generate an inventory for the Uinta Mountains containing 255 active rock glaciers. Active rock glaciers are 10.8 ha in area on average, and located at a mean elevation of 3290 m, where mean annual air temperature is 0.12 °C. The mean line-of-sight (LOS) velocity for the inventory is 2.52 cm/yr, but individual rock glaciers have LOS velocities ranging from 0.88 to 5.26 cm/yr. To search for relationships with climatic drivers, we investigate the time-dependent motion of three rock glaciers over the summers of 2016–2019. Time series analysis suggests that rock glacier motion has a significant seasonal component, with motion that is more than 5 times faster during the late summer compared to rest of the year. Rock glacier velocities also appear to be correlated with the snow-water equivalent of the previous winter's snowpack. These results demonstrate the ability to use satellite InSAR to monitor rock glaciers over large areas and provide insight into the environmental factors that control their kinematics.

Using InSAR to asses rock glacier movement in the Uinta Mountains, Utah

2020 ◽  
Author(s):  
George Brencher ◽  
Alexander Handwerger ◽  
Jeffrey Munroe
Keyword(s):  
Arid Regions ◽  
Interferometric Synthetic Aperture Radar ◽  
Rock Glacier ◽  
Uinta Mountains ◽  
Glacier Inventory ◽  
Rock Glaciers ◽  
Climatic Drivers ◽  
Glacier Velocity ◽  
Alpine Hydrology ◽  
Insight Into

<p>Rock glaciers are perennially frozen bodies of ice and rock debris that move downslope primarily due to deformation of internal ice. These features play an important role in alpine hydrology and landscape evolution, and constitute a significant water resource in arid regions. In the Uinta Mountains, Utah, nearly 400 rock glaciers have been identified on the basis of morphology, but the presence of ice has been investigated in only two. Here, I use satellite-based interferometric synthetic-aperture radar (InSAR) from the Copernicus Sentinel-1 satellites to identify and monitor active rock glaciers over a 10,000 km<sup>2 </sup>area. I also compare the time-dependent motion of several individual rock glaciers over the summers of 2016-2019 to search for relationships with climatic drivers such as precipitation and temperature. Sentinel-1 data from the August-October of 2016-2019 are used to create 79 interferograms of the entire Uinta range and are processed with the NASA/JPL/Stanford InSAR Scientific Computing Environment (ISCE) software package. Temporal baselines of intrayear interferograms range from 6-72 days. We use average velocity maps to generate an active rock glacier inventory for the Uinta Mountains containing 196 active rock glaciers. Average rock glacier velocity is 3 cm/yr in the line-of-sight direction, but individual rock glaciers have velocities ranging from 0.3-15 cm/yr. Rock glacier speeds do have a seasonal component, and were fastest in August across all years. One rock glacier reached a speed of 40 cm/yr over a 12 day interval from August 5 to August 17 of 2017. Preliminary results suggest that active rock glaciers are found at altitudes 10 m higher on average than inactive and relic rock glaciers identified in the previous inventory. Rock glacier movement did not accelerate between 2016 and 2019, suggesting that rock glaciers in this part of the Rocky Mountains are not speeding up over time. Our results highlight the ability to use satellite InSAR to monitor rock glaciers over large areas and provide insight into the factors that control their kinematics.</p>

scholarly journals Utility of late summer transient snowline migration rate on Taku Glacier, Alaska

2011 ◽  
Vol 5 (4) ◽  
pp. 1127-1133 ◽  
Author(s):  
M. Pelto
Keyword(s):  
Mass Balance ◽  
Migration Rate ◽  
Satellite Images ◽  
Snow Water Equivalent ◽  
Late Summer ◽  
Ablation Rate ◽  
Field Observations ◽  
Balance Assessment ◽  
Snow Water ◽  
The Mean

Abstract. On Taku Glacier, Alaska a combination of field observations of snow water equivalent (SWE) from snowpits and probing in the vicinity of the transient snowline (TSL) are used to quantify the mass balance gradient. The balance gradient derived from the TSL and SWE measured in snowpits at 1000 m from 1998–2010 ranges from 2.6–3.8 mm m−1. Probing transects from 950 m–1100 m directly measure SWE and yield a slightly higher balance gradient of 3.3–3.8 mm m−1. The TSL on Taku Glacier is identified in MODIS and Landsat 4 and 7 Thematic Mapper images for 31 dates during the 2004–2010 period to assess the consistency of its rate of rise and reliability in assessing ablation for mass balance assessment. For example, in 2010, the TSL was 750 m on 28 July, 800 m on 5 August, 875 m on 14 August, 925 m on 30 August, and 975 m on 20 September. The mean observed probing balance gradient was 3.3 mm m−1, combined with the TSL rise of 3.7 m day−1 yields an ablation rate of 12.2 mm day−1 from mid-July to mid-Sept, 2010. The TSL rise in the region from 750–1100 m on Taku Glacier during eleven periods each covering more than 14 days during the ablation season indicates a mean TSL rise of 3.7 m day−1, the rate of rise is relatively consistent ranging from 3.1 to 4.4 m day−1. This rate is useful for ascertaining the final ELA if images or observations are not available near the end of the ablation season. The mean ablation from 750–1100 m during the July–September period determined from the TSL rise and the observed balance gradient is 11–13 mm day−1 on Taku Glacier during the 2004–2010 period. The potential for providing an estimate of bn from TSL observations late in the melt season from satellite images combined with the frequent availability of such images provides a means for efficient mass balance assessment in many years and on many glaciers.

scholarly journals Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR

2013 ◽  
Vol 7 (4) ◽  
pp. 1109-1119 ◽  
Author(s):  
L. Liu ◽  
C. I. Millar ◽  
R. D. Westfall ◽  
H. A. Zebker
Keyword(s):  
Seasonal Variation ◽  
Sierra Nevada ◽  
Late Summer ◽  
Mean Value ◽  
Flow Speed ◽  
Surface Flow ◽  
Rock Glacier ◽  
Temporal Sampling ◽  
Rock Glaciers

Abstract. Despite the abundance of rock glaciers in the Sierra Nevada of California, USA, few efforts have been made to measure their surface flow. Here we use the interferometric synthetic aperture radar (InSAR) technique to compile a benchmark inventory describing the kinematic state of 59 active rock glaciers in this region. In the late summer of 2007, these rock glaciers moved at speeds that range from 14 cm yr−1 to 87 cm yr−1, with a regional mean value of 53 cm yr−1. Our inventory reveals a spatial difference: rock glaciers in the southern Sierra Nevada moved faster than the ones in the central Sierra Nevada. In addition to the regional mapping, we also conduct a case study to measure the surface flow of the Mount Gibbs rock glacier in fine spatial and temporal detail. The InSAR measurements over this target reveal (1) that the spatial pattern of flow is correlated with surface geomorphic features and (2) a significant seasonal variation of flow speed whose peak value was 48 cm yr−1in the fall of 2007, more than twice the minimum value observed in the spring of 2008. The seasonal variation lagged air temperatures by three months. Our finding on the seasonal variation of surface speed reinforces the importance of a long time series with high temporal sampling rates to detect possible long-term changes of rock glacier kinematics in a warming climate.

scholarly journals Utility of late summer transient snowline migration rate on Taku Glacier, Alaska

2011 ◽  
Vol 5 (3) ◽  
pp. 1365-1382
Author(s):  
M. Pelto
Keyword(s):  
Mass Balance ◽  
Migration Rate ◽  
Snow Water Equivalent ◽  
Late Summer ◽  
Ablation Rate ◽  
Field Observations ◽  
Snow Water ◽  
The Mean ◽  
The Difference ◽  
Thematic Mapper Imagery

Abstract. On Taku Glacier, Alaska a combination of field observations of snow water equivalent (SWE) from snowpits and probing in the vicinity of the transient snowline (TSL) are used to quantify the mass balance gradient. The balance gradient is determined from the difference in elevation and SWE from the TSL to snowpits at 1000 m from 1998–2010 and ranges from 2.6–3.8 mm m−1. Probing transects from 950 m–1100 m directly measure SWE and yield a slightly higher balance gradient of 3.3–3.8 mm m−1. TSL is identified in MODIS and Landsat 4 and 7 Thematic Mapper imagery for 31 dates during the 2004–2010 period on Taku Glacier to assess the consistency of its rate of rise and usefulness in assessing mass balance. In 2010, the TSL rose from 750 m on 28 July, 800 m on 5 August, 875 m on 14 August, 925 m on 30 August, and to 975 m on 20 September. The mean observed probing balance gradient was 3.3 mm m−1 and TSL rise was 3.7 m day−1, yielding an ablation rate of 12.2 mm day−1 on Taku Glacier from mid-July to mid-September. A comparison of the TSL rise in the region from 750–1100 m on Taku Glacier during eleven different periods of more than 14 days during the ablation season with repeat imagery indicates a mean TSL rise of 3.7 m day−1 on Taku Glacier, the rate of rise is relatively consistent ranging from 3.0 to 4.8 m day−1. This is useful for ascertaining the final ELA if imagery or observations are not available within a week or two of the end of the ablation season. From mid-July-mid-September the mean ablation from 750–1100 m determined from the TSL rise and the observed balance gradient varied from 11 to 18 mm day−1 on Taku Glacier during the 2004–2010 period.

Rock glacier impact on high-alpine freshwater chemistry

2020 ◽  
Author(s):  
Ulrike Nickus ◽  
Hansjoerg Thies ◽  
Karl Krainer ◽  
Richard Tessadri
Keyword(s):  
Major Ions ◽  
Stream Water ◽  
Summer Precipitation ◽  
Late Summer ◽  
European Alps ◽  
Rock Glacier ◽  
Ice Melt ◽  
Bedrock Weathering ◽  
Glacier Ice ◽  
Rock Glaciers

<p>Borehole soundings have revealed a warming of mountain permafrost of up to 1°C during recent decades. There is evidence that the increase in air temperature has favored the solute release from active rock glaciers, and pronounced changes in water quality of headwaters in the Alps have been described. Here, we report on solute concentrations of selected streams and springs in the vicinity of an active rock glacier in the Central European Alps (Lazaun, Italy). Stream water sampling started in 2007, and samples were analysed for major ions and heavy metals. We compare surface freshwaters of different origin and chemical characteristics, i.e. outflows of active and fossil rock glaciers, a spring emerging from a moraine and an ice glacier fed stream. Substance concentrations were highest in springs impacted by active rock glaciers, and dissolved ions increased up to a factor of 3 through the summer season. This pattern reflects a seasonally varying contribution to runoff by the melting winter snow pack, summer precipitation, baseflow and ice melt. Intense geochemical bedrock weathering of freshly exposed mineral surfaces, which are due to the downhill movement of the active rock glacier, is considered as a major reason for the high ion and metal concentrations in late summer runoff. In addition, solutes contained in the ice matrix of the rock glacier are released due to enhanced melting of rock glacier ice. On the contrary, minimum substance concentrations without any seasonal variability were found in the moraine spring.</p>

Distribution, evidence for internal ice, and possible hydrologic significance of rock glaciers in the Uinta Mountains, Utah, USA

2018 ◽  
Vol 90 (1) ◽  
pp. 50-65 ◽  
Author(s):  
Jeffrey S. Munroe
Keyword(s):  
Solar Radiation ◽  
Sea Level ◽  
Lake Water ◽  
Water Discharge ◽  
Late Summer ◽  
Significant Component ◽  
Uinta Mountains ◽  
Winter Ground ◽  
Ground Temperatures ◽  
Rock Glaciers

AbstractMapping at a scale of 1:5000 identified 395 rock glaciers in the Uinta Mountains, Utah. The majority of these have areas<20 ha, although the largest covers 97 ha. Rock glaciers have a mean elevation of 3285 m above sea level (range of 2820 to 3744 m above sea level) and exhibit a preference for northerly aspects. Sixty (15%) have a tongue-shaped morphology, whereas 335 (85%) are lobate features protruding from talus along valley walls. Tongue-shaped rock glaciers are found at significantly higher elevations and receive considerably less direct solar radiation each year than lobate rock glaciers. Winter ground temperatures atop representative rock glaciers drop to between −3°C and −5°C. This result, combined with ~0°C water discharging in the summer and water ages >1 year, suggests that at least some of these landforms contain buried ice. Late summer water discharge from two rock glaciers exhibits higher pH and significantly elevated concentrations of some ions compared with lake water, consistent with ablation of internal ice after melting of winter snowpack is complete. Although the amount of water discharging from individual rock glaciers may be small, the aggregate discharge from all rock glaciers and talus could constitute a significant component of streamflow in late summer and fall.

scholarly journals Brief communication: Application of a muonic cosmic ray snow gauge to monitor the snow water equivalent on alpine glaciers

2021 ◽  
Author(s):  
Rebecca Gugerli ◽  
Darin Desilets ◽  
Nadine Salzmann
Keyword(s):  
Snow Water Equivalent ◽  
Winter Season ◽  
Cosmic Ray ◽  
Promising Method ◽  
Harsh Environments ◽  
High Mountain ◽  
Mountain Regions ◽  
Mountain Environments ◽  
Alpine Glaciers ◽  
Snow Water

Abstract. Monitoring the snow water equivalent (SWE) in the harsh environments of high mountain regions is a challenge. Here, we explore the use of muon counts to infer SWE. We deployed a muonic cosmic ray snow gauge (µ-CRSG) on a Swiss glacier during the snow rich winter season 2020/21 (almost 2000 mm w.e.). The µ-CRSG measurements agree well with measurements by a neutronic cosmic ray snow gauge (n-CRSG) and they lie within the uncertainty of manual observations. We conclude that the µ-CRSG is a highly promising method to monitor SWE in remote high mountain environments with several advantages over the n-CRSG.

Rock glacier sediment, kinematics and geomorphometry: a study case from the Eastern Italian Alps

2021 ◽  
Author(s):  
Federica Minotti ◽  
Christian Kofler ◽  
Bernhard Gems ◽  
Volkmar Mair ◽  
Francesco Comiti
Keyword(s):  
High Mountain ◽  
Ice Melting ◽  
Italian Alps ◽  
Rock Glacier ◽  
Tauern Window ◽  
Transport Distance ◽  
Glacier System ◽  
Mountain Environments ◽  
Rock Glaciers ◽  
Unconsolidated Rock

&lt;p&gt;Rock glaciers are important geomorphological structures of high mountain environments and fundamental indicators for permafrost. They consist of unconsolidated rock debris &amp;#8211; generally derived from talus or till - held together by ice, moving slowly downslope due to the gravitation in combination with uncountable freeze-thaw-cycles in the active layer. The downslope movement of rock glaciers leads to lobate structures with depressed areas as well as ridges where the sediments tend to accumulate, creating a typical surface morphology defined as &quot;ridges and furrows&quot;. This study focuses on the analysis of one rock glacier system located in the Pfitsch/Vizze valley (South Tyrol), in the Eastern Italian Alps.&amp;#160; The debris in this area comprises exclusively the granitic Central Gneiss of the Tauern window. Rock glacier sediment derives from talus, consisting essentially of more or less foliated to planar angular material, which was essentially formed by frost weathering. The size and shape of sediments present at the surface of the rock glacier system were analyzed in correlation with displacement and geomorphometry, with the hypothesis that sediments shape and size at different sites across the rock glacier might relate to its past and present dynamics. The displacement analyses were carried out to quantify rock glaciers movements during the last 20 years, and the geomorphometrical characteristics were investigated to identify specific geometrical attributes that may be linked to internal ice changes.&lt;br&gt;Clasts analysis showed how rock glacier sediments are very heterogeneous, with dimensions being mainly determined by transport distance, and sphericity and roundness by lithology. A role of sediments characteristics on&amp;#160;displacement rate&amp;#160;did not turn out evident. Convexities and concavities observed on the study site are apparently created respectively by the accumulation of sediments and the collapse of the structure due to the internal ice melting. Indeed, the recent, marked increase in air temperature observed in the last decades in the Alps has likely caused an accelerated ice melting in the less protected &amp;#8211; in terms of solar radiation &amp;#8211; rock glaciers, as is the case for our study area. Sediments here are no longer bound by ice and have become rather unstable. Therefore, the monitoring of rock glaciers is fundamental to anticipate future changes in the type and magnitude of natural hazards originating at high elevations, as thicker layers of sediments are becoming increasingly unstable.&lt;/p&gt;

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