نتایج جستجو برای: glacier

تعداد نتایج: 7428  

2010
Denny M. CAPPS Bernhard RABUS John J. CLAGUE Daniel H. SHUGAR

The temporary storage and subsequent release of water at glacial margins can cause severe flooding in downstream areas and substantially impact glacier dynamics. Alpine subglacial lakes may not be identified until they become subaerially exposed or release a jökulhlaup. We use interferometric synthetic aperture radar (InSAR) to identify and characterize three dynamic alpine subglacial lakes of ...

Journal: :Remote Sensing 2017
Frank Paul Tazio Strozzi Thomas Schellenberger Andreas Kääb

The Karakoram mountain range is well known for its numerous surge-type glaciers of which several have recently surged or are still doing so. Analysis of multi-temporal satellite images and digital elevation models have revealed impressive details about the related changes (e.g., in glacier length, surface elevation and flow velocities) and considerably expanded the database of known surge-type ...

2017
Johan Jacob Mohr NQrvang Madsen

Multi baselinc rcpeat track interferometry (RTI) can potentially be uscd to measure both velocities and the micro topogra hy of glaciers. The Danish Center for Remote (DPC) has established a test cite for studies of glacier dynamics on the Storstreimmen glacier i n North East Greenland. DCRS has acquired RTI data over the glacier in 1994 and 1995 and ERS-112 tandem mode data are also available....

Journal: :Science 1985
B Kamb C F Raymond W D Harrison H Engelhardt K A Echelmeyer N Humphrey M M Brugman T Pfeffer

The hundredfold speedup in glacier motion in a surge of the kind the kind that took place in Variegated Glacier in 1982-1983 is caused by the buildup of high water pressure in the basal passageway system, which is made possible by a fundamental and pervasive change in the geometry and water-transport characteristics of this system. The behavior of the glacier in surge has many remarkable featur...

Journal: :Science 2005
A J Cook A J Fox D G Vaughan J G Ferrigno

The continued retreat of ice shelves on the Antarctic Peninsula has been widely attributed to recent atmospheric warming, but there is little published work describing changes in glacier margin positions. We present trends in 244 marine glacier fronts on the peninsula and associated islands over the past 61 years. Of these glaciers, 87% have retreated and a clear boundary between mean advance a...

2017
LAURA I. THOMSON LUKE COPLAND

Annual and seasonal surface velocities measured continuously from 1960 to 1970 at White Glacier, a 14 km long polythermal valley glacier spanning∼100–1800 m a.s.l., provide the most comprehensive early record of ice dynamics in the Canadian Arctic. Through comparison with differential GPSderived velocity data spanning 2012–16, we find reductions in mean annual velocity by 31 and 38% at lower el...

2015
Stewart S. R. Jamieson Marek W. Ewertowski David J. A. Evans

Rapid glacier advance is known to occur by a range of mechanisms. However, although large-scale debris loading has been proposed as a process for causing rapid terminus advance, it has rarely been observed. We use satellite remote sensing data to observe accelerated glacier terminus advance in response to massive supraglacial loading on two glaciers in Kyrgyzstan. Over a 15 year period, mining ...

2015
J. Krug G. Durand O. Gagliardini J. Weiss

Submarine melting of the calving face of tidewater glaciers and the mechanical back force applied by the ice mélange layer are two mechanisms generally proposed to explain seasonal variations at the calving front of tidewater glaciers. However, the way these processes affect the calving rate and glacier dynamics remains uncertain. In this study, we used a finite element-based model that solves ...

2016
Jean-Baptiste Bosson Christophe Lambiel

This contribution explores the internal structure of very small debris-covered glacier systems located in permafrost environments and their current dynamical responses to short-term climatic variations. Three systems were investigated with electrical resistivity tomography and dGPS monitoring over a 3-year period. Five distinct sectors are highlighted in each system: firn and bare-ice glacier, ...

Journal: :Science 2005
J Oerlemans

I constructed a temperature history for different parts of the world from 169 glacier length records. Using a first-order theory of glacier dynamics, I related changes in glacier length to changes in temperature. The derived temperature histories are fully independent of proxy and instrumental data used in earlier reconstructions. Moderate global warming started in the middle of the 19th centur...

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