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1

78 FR 26770 - NaturEner Wind Watch, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Commission [Docket No. ER13-1368-000] NaturEner Wind Watch, LLC; Supplemental Notice That Initial Market-Based Rate...notice in the above-referenced proceeding of NaturEner Wind Watch, LLC's application for market-based rate authority,...

2013-05-08

2

Glaciers, Water and Wind, Oh My!  

NSDL National Science Digital Library

This hands-on activity explores five different forms of erosion (chemical, water, wind, glacier and temperature). Students rotate through stations and model each type of erosion on rocks, soils and minerals. The students record their observations and discuss the effects of erosion on the Earth's landscape. Students learn about how engineers are involved in the protection of landscapes and structures from erosion. Math problems are included to help students think about the effects of erosion in real-world scenarios.

Integrated Teaching and Learning Program,

3

Changing winds cause melting of coastal Antarctic glaciers  

NASA Astrophysics Data System (ADS)

Anthropogenically induced changes in winds in the Southern Hemisphere are playing a key role in recent warming of subsurface waters around Antarctica, according to a new study by Spence et al. The warming water increases melting of coastal glaciers and thus could affect sea levels in the future.

Palus, Shannon

2014-11-01

4

Glacier winds in the Rongbuk Valley, north of Mount Everest: 1. Meteorological modeling with remote sensing data  

NASA Astrophysics Data System (ADS)

Persistent glacier winds blowing from noon to midnight in summer are present in the Rongbuk Valley, north of Mount Everest, with a maximum speed of 10 m s-1 and a vertical thickness as high as 1 km. These glacier winds may bring upper level atmosphere ozone to the surface, having a significant impact on the atmospheric environment. Such phenomena may be typical of the Tibetan Plateau, where most high mountains are covered by snow or glacier ice throughout the year. The Advanced Regional Prediction Model was used to simulate the down-valley flows, using realistic topography but neglecting synoptic winds. The modeling results agree well with the observations obtained in June 2002, revealing that the glacier winds are thermal flows primarily driven by the along-valley temperature gradient between the colder air over the glacier surface and the warmer air over surface areas covered by rock debris, which maintains air advection along the Rongbuk Valley. Downslope winds over the glacier slopes, especially from the western valley side, and the West Rongbuk Glacier, were forced by their inertia farther down into the valley and would intensify the glacier winds. The narrowing of the Rongbuk Valley could also speed up the glacier winds. Sensitivity tests showed that the detailed distribution of the Rongbuk Glacier, delineated by data from the Enhanced Thematic Mapper Plus on Landsat 7, plays an important role in glacier winds development. The glacier winds could be much weaker in winter when the area is completely snow covered.

Song, Yu; Zhu, Tong; Cai, Xuhui; Lin, Weili; Kang, Ling

2007-06-01

5

Glaciers  

NSDL National Science Digital Library

This interactive Flash exercise and animation explores glaciers, including their formation, growth, and retreat. This resource provides animations, diagrams, models in which students can see the influence of temperature and precipitation on glacier growth, and supplementary information that may serve as an overview or review of glaciers for introductory level physical geology or Earth science students at the high school or undergraduate level.

Smoothstone

6

Glaciers  

NSDL National Science Digital Library

This is a great site to help you learn about glaciers! On this webpage, you will learn what glaciers are, how they are formed, the different types of glaciers, their anatomy, how they move, and about glacial erosion. This site also has a model that helps you to understand glacial growth and retreat.

2010-01-01

7

77 FR 62504 - Combined Notice of Filings #1  

Federal Register 2010, 2011, 2012, 2013, 2014

...ER11- 4670-001. Applicants: NaturEner Glacier Wind Energy 1, LLC, NaturEner Glacier Wind Energy 2, LLC, NaturEner Power Watch...Description: Notice of Change in Facts of NaturEner Glacier Wind Energy 1, LLC, et al. Filed Date:...

2012-10-15

8

Glacier Area and Mass Variability in the Wind River Range (Wyoming, USA): 2006 to 2012  

NASA Astrophysics Data System (ADS)

The Wind River Range (WRR) is a continuous mountain range approximately 160 km in length in west-central Wyoming, USA. The Wind River Range is host to roughly 680 snow and ice bodies with 63 of these considered glaciers including seven of the ten largest glaciers in the American Rocky Mountains. The presence of glaciers results in meltwater contributions to streamflow during the late summer (July, August, and September - JAS) when snowmelt is decreasing, temperatures are high, precipitation is low, and irrigation demand peaks. Most studies indicate that the glaciers in the Wind River Range have been retreating since the 1850's, the approximate end of the Little Ice Age. Thus, the quantification of glacier meltwater (e.g., volume, mass) contributions to late-summer/early-fall streamflow is important given this resource is dwindling due to glacier recession. In this study, we selected glaciers in the WRR and obtained satellite products of study region. The ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) Level 1B imageries which are at 15 m spatial resolution between 2006~2012 were classified using supervised method and the glacier boundaries were extracted for tracking their changes. By combining ASTER L1B imageries of different years with two remote sensing derived DEM (Digital Elevation Model) datasets: ASTER GDEM (ASTER Global Digital Elevation), which is at 30 m spatial resolution and acquired prior to 2006 and Global Multi-resolution Terrain Elevation Data (GMTED 2010) which is at 250 m, 500 m and 1 km, and acquired in 2010, the 3D-view glacier volumetric loss extent could also be mapped and quantified. Assessing glacier area and volume variability is very important for evaluating and predicting glacier change in response to a changing environment.

Maloof, A.; Fang, B.; Tootle, G. A.; Lakshmi, V.; Kerr, G.

2013-12-01

9

Glaciers  

NSDL National Science Digital Library

Glaciers are found on every continent except Australia. This interactive feature provides an introduction to these moving streams of ice, which cover about 10 percent of Earth's land surface and hold between two and three percent of its water. Topics include what glaciers are, where and why they form, what influences their growth and decline, and how an apparently solid mass appears to flow like a river. There is also a brief description of some types of glaciers. A background essay and discussion questions are included.

10

Glacier winds in the Rongbuk Valley, north of Mount Everest: 2. Their role in vertical exchange processes  

Microsoft Academic Search

High ozone concentrations, combined with low humidity and strong, persistent glacier winds, were found at the surface of Rongbuk Valley, north of Mount Everest, with sharply increased ozone concentrations in their vertical profiles. Glacier winds and their roles in vertical exchange of the atmosphere were investigated numerically to understand the phenomena. A Lagrangian particle dispersion model was used to carry

Xuhui Cai; Yu Song; Tong Zhu; Weili Lin; Ling Kang

2007-01-01

11

Glacier winds in the Rongbuk Valley, north of Mount Everest: 1. Meteorological modeling with remote sensing data  

Microsoft Academic Search

Persistent glacier winds blowing from noon to midnight in summer are present in the Rongbuk Valley, north of Mount Everest, with a maximum speed of 10 m s-1 and a vertical thickness as high as 1 km. These glacier winds may bring upper level atmosphere ozone to the surface, having a significant impact on the atmospheric environment. Such phenomena may

Yu Song; Tong Zhu; Xuhui Cai; Weili Lin; Ling Kang

2007-01-01

12

Glaciers  

NSDL National Science Digital Library

In this online activity, learners adjust mountain snowfall and temperature to see how glaciers grow and shrink. They will use scientific tools to measure thickness, velocity and glacial budget. This activity includes an online simulation, sample learning goals, teaching ideas, and translations in over 20 languages.

Wendy Adams

2011-01-01

13

Wind-driven modulation of warm water supply to a proglacial fjord, Jorge Montt Glacier, Patagonia  

NASA Astrophysics Data System (ADS)

Projections of sea level rise due to ice loss from the land to the ocean have been hampered by a lack of understanding of the role the ocean is playing in glacier retreat, including the processes that contribute to the supply of warm water to the ice-ocean interface. Here shipboard, moored, and weather station data collected off Jorge Montt, a rapidly retreating glacier in Patagonia, are analyzed to understand the influence of wind forcing. During summer, synoptic-scale down-fjord wind events enhance an estuarine-like two-layer flow, increasing the inflow of oceanic deep water. During up-fjord wind events, the inflow of deep water is significantly reduced, and a three-layer exchange flow develops. Overall, along-fjord wind forcing is shown to modulate the inflow of warm water to the fjord by a factor of 2.5 The results suggest that local, channelized winds can be an important process modulating warm water supply and melting of tidewater glaciers.

Moffat, Carlos

2014-06-01

14

76 FR 62791 - Combined Notice of Filings #2  

Federal Register 2010, 2011, 2012, 2013, 2014

...ER11-4666-000. Applicants: NaturEner Glacier Wind Energy 1, LLC. Description: NaturEner Glacier Wind Energy 1, LLC submits tariff filing...ER11-4667-000. Applicants: NaturEner Glacier Wind Energy 2, LLC. Description:...

2011-10-11

15

77 FR 38044 - Combined Notice of Filings #1  

Federal Register 2010, 2011, 2012, 2013, 2014

...EG12-79-000. Applicants: NaturEner Glacier Wind Energy 1, LLC. Description: Notice...Wholesale Generator Status of NaturEner Glacier Wind Energy 1, LLC. Filed Date: 6...ER12-2057-000. Applicants: NaturEner Glacier Wind Energy 1, LLC. Description:...

2012-06-26

16

Wind influence on snow depth distribution and accumulation over glaciers  

Microsoft Academic Search

In mountain regions wind is known to cause snow redistribution. While physically based models of snow redistribution have been developed for flat to gently rolling terrain, extension of these findings to steep terrain has been limited by the complexity of wind fields in such areas. In this study, we applied a nonhydrostatic and compressible atmospheric prediction model to steep alpine

R. Dadic; R. Mott; M. Lehning; P. Burlando

2010-01-01

17

Man kan inte vlja och vraka bland naturens lagar  

E-print Network

1 Man kan inte välja och vraka bland naturens lagar Av Patrik Lindenfors (Från Humanisten rymden skulle ju all luft blåsa bort", kunde man till exempel påstå, med en argumentation som. Olika argument vägdes och värderades. Till slut nådde vetenskapen något som man kan kalla

Lindenfors, Patrik

18

Glacier winds in the Rongbuk Valley, north of Mount Everest: 2. Their role in vertical exchange processes  

NASA Astrophysics Data System (ADS)

High ozone concentrations, combined with low humidity and strong, persistent glacier winds, were found at the surface of Rongbuk Valley, north of Mount Everest, with sharply increased ozone concentrations in their vertical profiles. Glacier winds and their roles in vertical exchange of the atmosphere were investigated numerically to understand the phenomena. A Lagrangian particle dispersion model was used to carry out numerical experiments (forward-in-time simulations) and footprint analysis (backward-in-time simulations). The meteorological data inputs for these experiments were derived from the Advanced Regional Prediction System. Results showed that glacier winds may lead to significant downward transport of 1.5-2 km during the daytime from the northern slopes of Mount Everest. Glacier winds could advance down through the valley, with strong upward motions shown as a rolling up in front of their leading edge. Combining with upslope winds at two sidewalls of the valley or up-valley winds of tributaries, the lifting flows produced strong mixing of the atmosphere to a depth of approximately 3 km. Three-dimensional footprints derived from the particle dispersion model for the observational site, Rongbuk Monastery, clearly show influence from the mountainside of Mount Everest and from the southern part of the valley. The vertical extension of influence was as much as 2-3 km. Good correlation was found between the influence height and the ozone concentration. All the simulation results strongly indicate that the glacier winds and their related vertical exchange processes "pump down" ozone-rich air from upper levels to the surface of the valley.

Cai, Xuhui; Song, Yu; Zhu, Tong; Lin, Weili; Kang, Ling

2007-06-01

19

78 FR 64488 - Combined Notice of Filings #2  

Federal Register 2010, 2011, 2012, 2013, 2014

...Due: 5 p.m. ET 11/7/13. Docket Numbers: ER14-118-000. Applicants: NaturEner Glacier Wind Energy 1, LLC. Description: NaturEner Glacier Wind Energy 1, LLC submits tariff filing per 35.15: Notice of Cancellation of...

2013-10-29

20

Benchmark Glaciers  

NSDL National Science Digital Library

The United States Geological Survey (USGS) operates a long-term "benchmark" glacier program to intensively monitor climate, glacier motion, glacier mass balance, glacier geometry, and stream runoff at a few select sites. The data collected are used to understand glacier-related hydrologic processes and improve the quantitative prediction of water resources, glacier-related hazards, and the consequences of climate change. This page presents some of the balance, runoff, and temperature data for three glaciers: Gulkana, South Cascade and Wolverine. Reports for each of these glaciers uses the collected data to draw many conclusions. There is also a section with common questions and myths about glaciers.

21

Bivachnyy Glacier  

USGS Multimedia Gallery

Photograph of Bivachnyy Glacier, a surging valley glacier in the central Pamir Mountains. The glacier has a thick debris cover derived from adjacent mountains. Photograph courtesy of V.M. Kotlyakov, Russian Academy of Sciences, Moscow....

22

Glacier Melt  

NSDL National Science Digital Library

This short video shows an example of melting alpine glaciers in the Austrian Alps (Goldberg Glacier). Disappearing alpine glaciers have social and environmental impacts, including the decline of fresh water supplies and contributing to sea level rise.

National Geographic

23

Glacier Maker  

NSDL National Science Digital Library

This site contains hands-on activities that explore the structure of glaciers. Students identify the contents of a glacier like those found in Patagonia; construct a mini glacier model in class; and compare and contrast the classroom model with Patagonian glaciers. Topics included in this page are: Instructional objectives, background materials, activity, procedure, evaluation and web resources.

24

Glacier Physics  

NSDL National Science Digital Library

This site features a collection of visual resources about glaciers. Diagrams, images and animations reveal how a glacier forms, advances and retreats. These resources can be integrated into lectures, labs or other activities.

Francek, Mark

25

Glacier Webquest  

NSDL National Science Digital Library

A project to learn about ice cores and Antarctica. Use handout lab (Webquest: Glaciers) and follow instructions given for each procedure. Go to Ice Core Changes Go to Glacial Loss Go to Glacial Cover Animation Go to Snow Cover Go to Gulkana Glacier Home Page Go to Glacial Topography Go to Glacial Picture Archive Go to Additional Glacier Pictures ...

Mr. Kio

2008-11-06

26

Agassiz Glacier Glacier National Park, MT  

E-print Network

Agassiz Glacier Glacier National Park, MT Greg Pederson photo USGS USGS Repeat Photography Project Glacier Glacier National Park, MT Greg Pederson photo USGS USGS Repeat Photography Project http://nrmsc.usgs.gov/repeatphoto/ 2005 M. V. Walker photo courtesy of GNP archives1943 #12;Blackfoot ­ Jackson Glacier Glacier National

27

Fastest Glacier  

NSDL National Science Digital Library

This video from a 2005 NOVA program features scientists who study how the Jakobshavn Isbrae glacier in western Greenland is shrinking and moving faster due to increased melting over the past ten years. The video includes footage of scientists in the field explaining methods and animation of ice sheet dynamics leading to faster glacier movement.

NOVA scienceNOW

28

World Glacier Monitoring Service  

NSDL National Science Digital Library

The World Glacier Monitoring Service site contains online issues of Fluctuations of Glaciers and the Glacier Mass Balance Bulletin; glacier inventory data describing the spatial variability and glacier fluctuation data documenting changes in time; explanations of glacier monitoring strategy using glacier mass balance, length change, inventories, and data analysis; and a bibliography of related work.

29

Western Glacier Stonefly  

USGS Multimedia Gallery

The rare western glacier stonefly (Zapada glacier)is native to Glacier National Park and is seeking habitat at higher elevations due to warming stream temperature and glacier loss due to climatewarming. ...

30

Western Glacier Stonefly  

USGS Multimedia Gallery

The rare western glacier stonefly (Zapada glacier)is native to Glacier National Park and is seeking habitat at higher elevations due to warming stream temperature and glacier loss due to climatewarming. ...

31

Glacier Caves  

NSDL National Science Digital Library

Created by Charlie Anderson Jr. of the International Glaciospeleological Survey, Glacier Caves provides numerous fantastic photographs of glaciers, caves, and volcanoes located mainly in Northwestern United States. Visitors can sort through the images by topic or by location. Users can find various materials on eruptions, special features, and explorations of many famous Northwestern mountains including Mount St. Helens, Mount Hood, and Mount Rainer. The site features links to volcano web cameras.

32

Alaska Glaciers and Rivers  

NASA Technical Reports Server (NTRS)

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this image on October 7, 2007, showing the Alaska Mountains of south-central Alaska already coated with snow. Purple shadows hang in the lee of the peaks, giving the snow-clad land a crumpled appearance. White gives way to brown on the right side of the image where the mountains yield to the lower-elevation Susitna River Valley. The river itself cuts a silver, winding path through deep green forests and brown wetlands and tundra. Extending from the river valley, are smaller rivers that originated in the Alaska Mountains. The source of these rivers is evident in the image. Smooth white tongues of ice extend into the river valleys, the remnants of the glaciers that carved the valleys into the land. Most of the water flowing into the Gulf of Alaska from the Susitna River comes from these mountain glaciers. Glacier melt also feeds glacier lakes, only one of which is large enough to be visible in this image. Immediately left of the Kahiltna River, the aquamarine waters of Chelatna Lake stand out starkly against the brown and white landscape.

2007-01-01

33

Melting Glaciers  

NSDL National Science Digital Library

Due to the potential disastrous consequences to the environment and to numerous societies, scientists, governments, and civilians are concerned with the growing trend of glacial melt. This topic-in-depth explores various geographic regions where this phenomenon has recently been observed. Providing background into the study of glaciology, this report begins with a Web site (1) discussing the unique features of glaciers. The US Army Corps of Engineers offers visitors an insight to glacial properties including their locations, movements, and influences; along with a series educational images. The second site (2) explains the exceptionality of the two hundred sixty six glaciers at Glacier National Park. Through a collection of images, animations, and pictures provided by the National Park Service, users can learn about ice dams, climatic impacts, and the erosive powers of ice and water. The rest of the topic-in-depth discusses findings of glacial melting from around the world. NASA (3) addresses the Artic warming's affects on glacier formations. This Web site provides a few animations displaying ice sheet extent and the cracking of icebergs. On a positive note, visitors can learn how the decrease in glaciers has opened up new habitat for some Artic species. The next Web site (4), also by NASA, discusses the findings of a twenty-five year study of Patagonia's glaciers. Educators and students can discover how NASA utilized the Space Shuttle Endeavor to study the entire 17,200 square kilometer region. The site also discusses potential causes of the melting in this region, which has contributed to almost ten percent of the global sea-level change from mountain glaciers. As reported by the BBC (5), Dr. Harrison at the University of Oxford has determined that the glaciers in parts of Kazakhstan have been decreasing annually by almost two cubic kilometers between 1955 and 2000. Visitors can learn how the melting of these four hundred sixteen glaciers will adversely affect the region's rivers and its water supply. The Taipei Times (6) reports that the Swiss Alpine glacial melting has probably intensified due to this summer's record-breaking heat wave. This Web site provides short, intriguing descriptions of consequences of the "rush of melt water streaming from the ice wall." Users can learn about predictions in the 1990s that the glaciers would shrink to ten percent of their 1850 size by the end of the twenty first century. In the next Web site (7), the BBC provides a captivating illustration of the effects the Peruvian glacial melts may have on tourism, the country's water supply, and more. Students and educators can learn about NASA studies showing cracks in the ice, which could lead to the flooding of large cities. Visitors can also find out how the recent glacier recessions have affected some ancient spiritual traditions. The last site, by the USGS, (8) features excerpts from Myrna Hall and Daniel Fagre's 2003 research paper in BioScience. Visitors can discover the melt rate and spatial distributions of glaciers for two possible future climate situations. Providing an amazing animation, users will be amazed by the changes predicted by the model.

Enright, Rachel

34

Glaciers and Global Climate  

NASA Technical Reports Server (NTRS)

Glaciers are important indicators of global climate. Glacier recession, as observed from space and in the field, has been occurring for about 100 years. The present extent of glaciers and glaciers in the last Ice Age will be discussed. I will show slides of field work on glaciers and show instruments used to measure ice and snow. I will discuss reasons for studying glaciers and why remote sensing is important for glacier studies.

Hall, Dorothy K.

1999-01-01

35

Fast tidewater glaciers  

Microsoft Academic Search

Some iceburg-calving outlet glaciers flow continuously at speeds normally associated with surging glaciers and exhibit dramatic instability scenarios related to those suggested for marine ice sheets. No temperature tidewater glaciers are known to have floating termini, but many polar and subpolar tidewater glaciers do. The fast flow of temperature calving glaciers is almost entirely due to basal sliding and appears

M. F. Meier; Austin Post

1987-01-01

36

Glacier Photograph Collection  

NSDL National Science Digital Library

These repeat photographs (also known as glacier pairs) are of special interest to scientists studying glaciers and climate. Glacier photographs taken from the same vantage point, but years apart in time, can reveal dramatic changes in the glacier terminus position, as a glacier either advances or retreats. Most glaciers around the world have retreated at unprecedented rates over the last century. These pairs of photographs can provide striking visual evidence of climate change.

National Snow and Ice Data Center

37

Northeast Glaciers  

NSDL National Science Digital Library

This reference guide provides a brief review of glaciers in the Northeastern U.S. It then focuses on the glacial affects in four areas, an inland basin near the Finger Lakes area of New York, the Appalachian/Piedmont through New York and Pennsylvania, the coastal plain and the exotic terrane of New England. Topics covered include glacial scouring, glacial deposits and periglacial features.

2003-01-01

38

Shepard Glacier, Glacier National Park, Montana - 2005  

USGS Multimedia Gallery

The thick, crevassed, ice flows of historic Shepard Glacier have been diminished to less than 0.1 square kilometer in area by 2005. According to the criteria set by the USGS Repeat Photography Project, Shepard Glacier is now considered to be too small to be defined as a glacier. (Blase Reardon)...

39

Mendenhall Glacier Juneau, Alaska  

E-print Network

· · · · · · #12;V1 Mendenhall Glacier Juneau, Alaska 404 Alaskan Frontiers & Glaciers V1 PRSRTSTD U blend of nature and modern culture. Marvel at the spectacular Hubbard Glacier, the longest tidewater glacier in Alaska and visit Icy Strait Point, a seaport nestled in the lush, seemingly endless northern

Raina, Ramesh

40

Muir Glacier Retreats  

USGS Multimedia Gallery

Muir Glacier has retreated out of the field of view and is now nearly 5 miles to the northwest. Riggs Glacier has retreated as much as 2000 ft and thinned by more than 800 feet. Note the dense vegetation that has developed. Also note the correlation between Muir Glaciers 1941 thickness and th...

41

Muir Glacier in Glacier Bay National Monument 1941  

USGS Multimedia Gallery

This August 1941 photograph is of Muir Glacier in Glacier Bay National Monument, Alaska. It shows the lower reaches of Muir Glacier, then a large, tidewater calving valley glacier and its tributary, Riggs Glacier. For nearly two centuries before 1941, Muir Glacier had been retreating. In places, a t...

42

Glacier inventory of the upper Huasco valley, Norte Chico, Chile: glacier characteristics, glacier change and comparison with  

E-print Network

Glacier inventory of the upper Huasco valley, Norte Chico, Chile: glacier characteristics, glacier Chile, Portugal 84, Casilla 3387, Santiago, Chile ABSTRACT. Results of a new glacier inventory identified, and glaciers with surface areas glacierized area and 3% of the water

Rabatel, Antoine

43

Online Glacier Photograph Database  

NSDL National Science Digital Library

This image collection from the National Snow and Ice Data Center features 14 pairs of Alaskan glacier photographs. Each photographic pair consists of a late-19th or early-20th century photograph and a 21st century photograph taken from the same location. The comparative photographs clearly show substantial changes in glacier position and size and document significant landscape evolution and vegetative succession. The site also provides links to pairs of photographs of glaciers in Switzerland, a repeat photography project at Glacier National Park by the USGS, a glacier database which features satellite images and maps, and further information on glaciers.

The National Snow and Ice Data Center (NSIDC)

44

Glacier Hazards From Space  

NSDL National Science Digital Library

This interactive slide show presents aerial photographs of seven glaciers worldwide. All of the glaciers present some form of hazard due to the rapid melting of mountain glaciers and a detailed explanation is given for each. Two of the photos contain superimposed before and after photographs and a sliding line which allows the viewer to alternate the two views. Locations of the glaciers include Bhutan and Nepal, Russia and Italy, as well as Alaska in the United States.

45

Afghanistan Glacier Diminution  

Microsoft Academic Search

Glaciers in Afghanistan represent a late summer - early fall source of melt water for late season crop irrigation in a chronically drought-torn region. Precise river discharge figures associated with glacierized drainage basins are generally unavailable because of the destruction of hydrological gauging stations built in pre-war times although historic discharge data and prior (1960s) mapped glacier regions offer some

J. F. Shroder; M. Bishop; U. Haritashya; J. Olsenholler

2008-01-01

46

Glaciers Then and Now  

NSDL National Science Digital Library

In this activity, students compare 2 photographs (with time span of 30-100 years between photos) of specific Alaskan glaciers to observe how glaciers have changed over the time interval. Activity is a good kickoff for learning about glaciology - how and why glaciers form, grow and shrink, and their relation to climate change.

2007-01-01

47

World Glacier Inventory  

NSDL National Science Digital Library

The National Snow and Ice Data Center (NSIDC) provides the World Glacier Inventory data, which was collected by the World Glacier Monitoring Service. This inventory contains geographic location, area, length, orientation, elevation, and classification of morphological type and moraines of more than 67,000 glaciers throughout the world. The data may be downloaded via FTP or through form-based queries.

48

Glacier (?) National Park  

NSDL National Science Digital Library

Spreadsheets Across the Curriculum/Geology of National Parks module. Students examine data about the disappearing glaciers in the park; after calculating percentage change in the number of glaciers from 1850 to 2000, they interpolate to estimate when Grinnell glacier will be gone.

Module by: Judy McIlrath, University of South Florida Cover Page by: Len Vacher and Denise Davis, University of South Florida

49

Glacier Ecosystems of Himalaya  

NASA Astrophysics Data System (ADS)

Biological activity on glaciers has been believed to be extremely limited. However, we found various biotic communities specialized to the glacier environment in various part of the world, such as Himalaya, Patagonia and Alaska. Some of these glacier hosted biotic communities including various cold-tolerant insects, annelids and copepods that were living in the glacier by feeding on algae and bacteria growing in the snow and ice. Thus, the glaciers are simple and relatively closed ecosystems sustained by the primary production in the snow and ice. In this presentation, we will briefly introduce glacier ecosystems in Himalaya; ecology and behavior of glacier animals, altitudinal zonation of snow algal communities, and the structure of their habitats in the glacier. Since the microorganisms growing on the glacier surface are stored in the glacial strata every year, ice-core samples contain many layers with these microorganisms. We showed that the snow algae in the ice-core are useful for ice core dating and could be new environmental signals for the studies on past environment using ice cores. These microorganisms in the ice core will be important especially in the studies of ice core from the glaciers of warmer regions, in which chemical and isotopic contents are often heavily disturbed by melt water percolation. Blooms of algae and bacteria on the glacier can reduce the surface albedo and significantly affect the glacier melting. For example, the surface albedo of some Himalayan glaciers was significantly reduced by a large amount of dark-colored biogenic material (cryoconite) derived from snow algae and bacteria. It increased the melting rates of the surfaces by as much as three-fold. Thus, it was suggested that the microbial activity on the glacier could affect the mass balance and fluctuation of the glaciers.

Kohshima, S.; Yoshimura, Y.; Takeuchi, N.; Segawa, T.; Uetake, J.

2012-12-01

50

The World Glacier Inventory  

NSDL National Science Digital Library

This web site is part of the National Snow and Ice Data Center's World Glacier Monitoring Service. The World Glacier Inventory contains information for over 67,000 glaciers throughout the world. Parameters within the inventory include: geographic location, area, length, orientation, elevation, and classification of morphological type and moraines. The inventory entries are based upon a single observation in time and can be viewed as a "snapshot" of the glacier at this time. These data are collected and digitized by the World Glacier Monitoring Service, Zurich. A point and click map of the world will also take users to the region of interest with a list of glaciated areas.

C. Haggerty

51

Worthington Glacier Project  

NSDL National Science Digital Library

Funded by the National Science Foundation (NSF), the Worthington Glacier Project is a collaboration between researchers at the University of Wyoming and the University of Colorado. The objective of this project is to understand glacier flow dynamics "by comparing detailed measurements of glacier motion with numerical models for glacier flow." Summaries and diagrams are provided of the discussed topics: Borehole Video Observations, Radio-Echo Sounding, Crevassing, Surface Flow Field, Englacial Flow Field, 3-D Flow Field, and In-Situ Stress. Images of the Worthington Glacier fieldwork, future research, and publications are also available at the site.

52

Fast tidewater glaciers  

NASA Astrophysics Data System (ADS)

Some iceberg-calving outlet glaciers flow continuously at speeds normally associated with surging glaciers arid exhibit dramatic instability scenarios related to those suggested for marine ice sheets. No temperate tidewater glaciers are known to have floating termini, but many polar and subpolar tidewater glaciers do. The fast flow of temperate calving glaciers is almost entirely due to basal sliding and appears to be a function of the effective pressure on the bed, which may approach zero, and the longitudinal back stress on the terminus. The terminus boundary condition (the calving relation) is imperfectly known yet is vital to the dynamics of these glaciers. Calving relations for grounded tidewater glaciers have been suggested on empirical grounds but have not been rigorously tested; the calving relations for floating termini are virtually unknown. This, together with the imperfect understanding of basal sliding, inhibits confidence in our understanding of the stability of these glaciers. Columbia Glacier (Alaska) is an instructive example because observations have been made on the major changes in its geometry, calving rate, and dynamics that have occurred in less than 10 years. The calving flux has increased more rapidly than the glacier flux, causing thinning and retreat; as a result, the ice velocity has increased markedly. The short-term velocity changes relate to changes in back pressure (ice recession, tidal changes) and the flux of water injected to the bed. These results have relevance to the mechanisms of basal sliding, glacier surges, and the stability of marine ice streams.

Meier, M. F.; Post, Austin

1987-08-01

53

Glaciers of Asia  

USGS Publications Warehouse

This chapter is the ninth to be released in U.S. Geological Survey Professional Paper 1386, Satellite Image Atlas of Glaciers of the World, a series of 11 chapters. In each of the geographic area chapters, remotely sensed images, primarily from the Landsat 1, 2, and 3 series of spacecraft, are used to analyze the specific glacierized region of our planet under consideration and to monitor glacier changes. Landsat images, acquired primarily during the middle to late 1970s and early 1980s, were used by an international team of glaciologists and other scientists to study various geographic regions and (or) to discuss related glaciological topics. In each glacierized geographic region, the present areal distribution of glaciers is compared, wherever possible, with historical information about their past extent. The atlas provides an accurate regional inventory of the areal extent of glacier ice on our planet during the 1970s as part of a growing international scientific effort to measure global environmental change on the Earth?s surface. The chapter is divided into seven geographic parts and one topical part: Glaciers of the Former Soviet Union (F-1), Glaciers of China (F-2), Glaciers of Afghanistan (F?3), Glaciers of Pakistan (F-4), Glaciers of India (F-5), Glaciers of Nepal (F?6), Glaciers of Bhutan (F-7), and the Paleoenvironmental Record Preserved in Middle-Latitude, High-Mountain Glaciers (F-8). Each geographic section describes the glacier extent during the 1970s and 1980s, the benchmark time period (1972-1981) of this volume, but has been updated to include more recent information. Glaciers of the Former Soviet Union are located in the Russian Arctic and various mountain ranges of Russia and the Republics of Georgia, Kyrgyzstan, Tajikistan, and Kazakstun. The Glacier Inventory of the USSR and the World Atlas of Ice and Snow Resources recorded a total of 28,881 glaciers covering an area of 78,938 square kilometers (km2). China includes many of the mountain-glacier systems of the world including the Himalaya, Karakorum, Tien Shan and Altay mountain ranges. The glaciers are widely scattered and cover an area of about 59,425 km2. The mountain glaciers may be classified as maritime, subcontinental or extreme continental. In Afghanistan, more than 3,000 small glaciers occur in the Hindu Kush and Pamir mountains. Most glaciers occur on north-facing slopes shaded by mountain peaks and on east and southeast slopes that are shaded by monsoon clouds. The glaciers provide vital water resources to the region and cover an area of about 2,700 km2. Glaciers of northern Pakistan are some of the largest and longest mid-latitude glaciers on Earth. They are located in the Hindu Kush, Himalaya, and Karakoram mountains and cover an area of about 15,000 km2. Glaciers here are important for their role in providing water resources and their hazard potential. The glaciers in India are located in the Himalaya and cover about 8,500 km2. The Himalaya contains one of the largest reservoirs of snow and ice outside the polar regions. The glaciers are a major source of fresh water and supply meltwater to all the rivers in northern India, thereby affecting the quality of life of millions of people. In Nepal, the glaciers are located in the Himalaya as individual glaciers; the glacierized area covers about 5,324 km2. The region is the highest mountainous region on Earth and includes the Mt. Everest region. Glaciers in the Bhutan Himalaya have a total area of about 1,317 km2. Many recent glacier studies are focused on glacier lakes that have the potential of generating dangerous glacier lake outburst floods. Research on the glaciers of the middle-latitude, high-mountain glaciers of Asia has also focused on the information contained in the ice cores from the glaciers. This information helps in the reconstruction of paleoclimatic records, and the computer modeling of global climate change.

Williams, Richard S., Jr.; Ferrigno, Jane G.

2010-01-01

54

Alaskan Glaciers and Glacier-Outburst Floods (Jkulhlaups)  

Microsoft Academic Search

Alaska has more than 50,000 glaciers, including about 2,000 valley glaciers. Nearly all Alaskan glaciers are temperate. Many Alaskan valley glaciers end in ice-marginal lakes formed by terminal or recessional moraines. Some Alaskan valley glaciers act as ice dams, forming lakes by blocking side valleys or by extending into adjacent valleys. Many Alaskan glaciers store large quantities of water in

B. F. Molnia

2009-01-01

55

Afghanistan Glacier Diminution  

NASA Astrophysics Data System (ADS)

Glaciers in Afghanistan represent a late summer - early fall source of melt water for late season crop irrigation in a chronically drought-torn region. Precise river discharge figures associated with glacierized drainage basins are generally unavailable because of the destruction of hydrological gauging stations built in pre-war times although historic discharge data and prior (1960s) mapped glacier regions offer some analytical possibilities. The best satellite data sets for glacier-change detection are declassified Cornona and Keyhole satellite data sets, standard Landsat sources, and new ASTER images assessed in our GLIMS (Global Land Ice Measurements from Space) Regional Center for Southwest Asia (Afghanistan and Pakistan). The new hyperspectral remote sensing survey of Afghanistan completed by the US Geological Survey and the Afghanistan Ministry of Mines offers potential for future detailed assessments. Long-term climate change in southwest Asia has decreased precipitation for millennia so that glaciers, rivers and lakes have all declined from prehistoric and historic highs. As many glaciers declined in ice volume, they increased in debris cover until they were entirely debris-covered or became rock glaciers, and the ice was protected thereby from direct solar radiation, to presumably reduce ablation rates. We have made a preliminary assessment of glacier location and extent for the country, with selected, more-detailed, higher-resolution studies underway. In the Great Pamir of the Wakhan Corridor where the largest glaciers occur, we assessed fluctuations of a randomly selected 30 glaciers from 1976 to 2003. Results indicate that 28 glacier-terminus positions have retreated, and the largest average retreat rate was 36 m/yr. High albedo, non-vegetated glacier forefields formed prior to 1976, and geomorphological evidence shows apparent glacier-surface downwasting after 1976. Climatic conditions and glacier retreat have resulted in disconnection of tributary glaciers to their main trunk, the formation of high-altitude lakes, and an increased frequency and size of proglacial lakes that are, however, genrally unavailable for irrigation sources. Similar conditions of glacier diminution have occurred in almost all other high altitude parts of the country. Generally decreased precipitation in all seasons, coupled with decreased glacier storage of potential melt-water, augers continued severe problems for beleaguered Afghanistan agriculture, along with concomitant social problems as a result.

Shroder, J. F.; Bishop, M.; Haritashya, U.; Olsenholler, J.

2008-12-01

56

All about glaciers  

NSDL National Science Digital Library

The National Snow and Ice Data Center created this website to educate everyone, from grade school students to glaciologists, about glaciers. At the Data and Science link, researchers can learn about glaciological organizations, publications, and research projects as well as how to obtain glacial data. Students and educators can find a glaciology glossary, answers to many of their questions, and amazing images of glaciers at the General Information link. The website also provides a detailed portrayal of the life of glaciers.

57

Glaciers and Climate Change  

Microsoft Academic Search

Although my book focuses on valley glaciers, it is not intended\\u000ato provide a basic course in glaciology, nor does it claim to\\u000agive a state-of-the-art picture of glacier research. It consists\\u000amainly of the personal reflections of a meteorologist who\\u000agradually became interested in glaciers and is written primarily\\u000afor persons with a general interest in the physics of

J. Oerlemans

2001-01-01

58

Glacier Hazards from Space  

NSDL National Science Digital Library

This "Science Now" feature from the Public Broadcasting Service (PBS) television program "Nova" shows students how remote sensing by satellites can be used to monitor and evaluate hazards presented by glaciers as the climate becomes warmer, causing the glaciers to melt. The feature, which can be presented as a slide show, consists of 11 satellite images with brief written descriptions that explain such hazards as ice collapses and avalanches, flooding by meltwater, and bursting glacier lakes.

59

Moving Model Glacier  

NSDL National Science Digital Library

In this goopy activity, learners will model glacial movement with gak, a white glue and liquid starch mixture. Each fist-sized gob of gak represents a years worth of snow, accumulating to form a glacier on a model landscape. Learners will record the gaks rate of travel as well as make observations of other glacier behaviors. Relates to the linked video, DragonflyTV GPS: Glaciers.

Twin Cities Public Television, Inc.

2007-01-01

60

Glaciers: Teacher's Guide  

NSDL National Science Digital Library

The Glaciers Teacher's Guide Web site was created by Arizona educator Patti Greenleaf. The site provides everything needed to complete the online activity, which is geared to students in grades 4 to 5. Objectives of the lesson include having students define what a glacier is, correctly use some terminology related to glaciers, describe how they form and move, and finally be able to tell where glaciers are located today. These objectives are accomplished by having the students read the provided text as well as looking at various photographs and movies. The structure and material of the site are its highlight, both of which are simple but effective.

Nichols, Marilyn.

1969-12-31

61

The thermophysics of glaciers  

SciTech Connect

This volume presents the results of experimental and theoretical work on the thermodynamics of ice sheets and glaciers. The author has carried out extensive field work in both the Soviet Union and Antarctica over the last 25 years and has contributed to the understanding of the thermophysics of glaciers. The topics covered in this volume embrace heat flow measurement and temperature distributions in glaciers, the thermal drilling of glaciers, the melting and freezing of ice sheets, and other thermophysical problems. Also included are topics of relevance to glacial engineering.

Zotikov, I.A.

1986-01-01

62

Glaciers and Icebergs  

NSDL National Science Digital Library

This lesson plan provides instruction to teachers for creating a glacier in the classroom to demonstrate how glaciation affects landforms. Learning objectives include student understanding that as glaciers move, they create a variety of patterns on landforms by a process called glacial scraping, that the scraping patterns left by a glacier depend on how the glacier moved over the landform, and that the evidence of glaciation left by glacial scraping provides clues to the climate in a particular place over a long period of time. The site also includes relevant vocabulary words with sound recordings for pronunciation. There are ideas presented for more advanced activities, discussion questions, and additional sources to consult.

Frank Weisel

63

Wind  

NSDL National Science Digital Library

What part does the wind play in satisfying energy demands? This informational piece, part of a series about the future of energy, introduces students to wind as an energy source. Here students read about the history, uses, and efficiency of wind power. Information is also provided about benefits, limitations, and geographical considerations of wind power in the United States. Thought-provoking questions afford students chances to reflect on what they've read about the uses of wind power. Supplemental articles and information are available from a sidebar. Three energy-related web links are also provided. Copyright 2005 Eisenhower National Clearinghouse

Iowa Public Television. Explore More Project

2004-01-01

64

Retreat of Glaciers in Glacier National Park In Glacier National Park (GNP), MT some effects of global  

E-print Network

Retreat of Glaciers in Glacier National Park In Glacier National Park (GNP), MT some effects of global climate change are strikingly clear. Glacier recession is underway, and many glaciers have already disappeared. The retreat of these small alpine glaciers reflects changes in recent climate as glaciers respond

65

2. HORSESHOE CURVE IN GLACIER POINT ROAD NEAR GLACIER POINT. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. HORSESHOE CURVE IN GLACIER POINT ROAD NEAR GLACIER POINT. HALF DOME AT CENTER REAR. LOOKING NNE. GIS N-37 43 44.3 / W-119 34 14.1 - Glacier Point Road, Between Chinquapin Flat & Glacier Point, Yosemite Village, Mariposa County, CA

66

HORSESHOE CURVE IN GLACIER POINT ROAD NEAR GLACIER POINT. HALF ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

HORSESHOE CURVE IN GLACIER POINT ROAD NEAR GLACIER POINT. HALF DOME AT CENTER REAR. SAME VIEW AT CA-157-2. LOOKING NNE. GIS: N-37' 43 44.3 / W-119 34 14.1 - Glacier Point Road, Between Chinquapin Flat & Glacier Point, Yosemite Village, Mariposa County, CA

67

Glaciers and Rocks  

NSDL National Science Digital Library

This formative assessment item uncovers students' ideas about glacial erosion and how glaciers transport rocks and other sediment. The assessment is aligned with the National Science Education Standards. It contains instructional suggestions as well as links to other helpful resources dealing with glaciers and glacial movement.

Jessica Fries-Gaither

68

Mini Glacier Meltdown  

NSDL National Science Digital Library

This activity (located on page 3 of the PDF) is a full inquiry investigation about the different causes of glacial melt. Groups of learners will design their own experiment using frozen "glaciers", bricks and different energy sources (fans, and lights) to test how different conditions affect the rate of melting. The results might be surprising. Relates to linked video, DragonflyTV GPS: Glaciers.

Twin Cities Public Television, Inc.

2007-01-01

69

Denali Fault: Susitna Glacier  

USGS Multimedia Gallery

Helicopters and satellite phones were integral to the geologic field response. Here, Peter Haeussler is calling a seismologist to pass along the discovery of the Susitna Glacier thrust fault. View is to the north up the Susitna Glacier. The Denali fault trace lies in the background where the two lan...

70

Melting Mountain Glaciers  

NSDL National Science Digital Library

The world's glaciers are shrinking at alarming rates, and many scientists believe it is due to changes in climate. Dr. Lonnie Thompson of Ohio State University and Dr. Douglas Hardy of UMass-Amherst discuss glaciers and how they melt, and pay special attention to Africa's tallest mountain, Mt. Kilimanjaro. "Changing Planet" is produced in partnership with the National Science Foundation.

NBC Learn

2010-10-07

71

Glacier Peak, Washington  

NSDL National Science Digital Library

This site features links to all aspects of Glacier Peak, a volcano in the Cascade Range, including its geographic setting, and geologic and eruptive history. Glacier Peak is not prominently visible from any major metropolitan centers, and thus its attractions, as well as its hazards, tend to be overlooked. Yet, Glacier Peak has produced larger and more explosive eruptions than any other Washington volcano except Mount St. Helens. Glacier Peak was not known by settlers to be a volcano until the 1850s, when Native Americans mentioned it to naturalist George Gibbs. Not until 1898 did Glacier Peak appear on a published map under its current name. Links labeled 'Special Items of Interest' include information about volcanic highlights and features, and points of interest. Other links lead to maps, graphics, images, publications, reports, and other items of interest involving this volcano and others.

72

2008 Wind Energy Projects, Wind Powering America (Poster)  

SciTech Connect

The Wind Powering America program produces a poster at the end of every calendar year that depicts new U.S. wind energy projects. The 2008 poster includes the following projects: Stetson Wind Farm in Maine; Dutch Hill Wind Farm in New York; Grand Ridge Wind Energy Center in Illinois; Hooper Bay, Alaska; Forestburg, South Dakota; Elbow Creek Wind Project in Texas; Glacier Wind Farm in Montana; Wray, Colorado; Smoky Hills Wind Farm in Kansas; Forbes Park Wind Project in Massachusetts; Spanish Fork, Utah; Goodland Wind Farm in Indiana; and the Tatanka Wind Energy Project on the border of North Dakota and South Dakota.

Not Available

2009-01-01

73

National Park Glaciers Knowledge Center  

NSDL National Science Digital Library

This interactive resource explains what glaciers are, where they are found, how they form, and how they move. The types and parts of glaciers are discussed, as well as ice ages, the different types of landforms that may result from glaciation, and how scientists monitor glaciers. Examples from our national parks are also highlighted as case studies to illustrate how glaciers have created landscapes.

2005-08-01

74

Modeling Glacier Erosion Through Time  

NSDL National Science Digital Library

Prior to this lab, students will have read and learned about valley glacier processes, glacier mass balance, warm-based and cold-based glaciers, and can identify various glacier landforms formed by erosion. They will also have had an introductory lecture on ice physics, but that is not necessary to complete this activity.

Cathy L Connor

75

On turbulent heat flux contributions to the energy balance at the Opabin Glacier, Yoho National Park, Canada  

Microsoft Academic Search

Turbulent heat flux and its contribution to energy balance is investigated at two glaciers in the Canadian Rockies. Detailed profile measurements of wind, temperature, and humidity in the lower boundary layer above the Opabin Glacier reveal a predominantly stable boundary layer regime. Wind speeds generally increase with height and temperature profiles are predominantly logarithmic in nature, however humidity profiles do

Mira Losic

2009-01-01

76

Hydrometeorology of a high Arctic glacier  

NASA Astrophysics Data System (ADS)

Field studies of John Evans Glacier (JEG), Ellesmere Island, (79 40' N, 74 30' W) were used to investigate Arctic glacier melt, runoff and mass balance (MB) response to climate change. Seasonal development of glacier drainage is driven by a hydrofracture process: meltwater-filled crevasses propagate from the glacier surface to the bed, forcing a connection between the supra- and subglacial drainage systems. Given the importance of surface meltwater in this process, the melt response of a high wind/high air temperature event (28-30 July, 2000) was examined. Results show that this event produced 30% of total seasonal melt, strongly contributing to negative MB conditions in 2000. The timing and frequency of such events therefore critically impacts both seasonal drainage development and interannual variability in Arctic glacier MB. Field measurements at JEG highlight problems inherent in current MB models. Models assume constant negative summer air temperature lapse rates (STLR) and positive winter accumulation lapse rates (WALR) over glacier surfaces. Results show that STLR and WALR are highly spatially and temporally variable: STLR is often positive, and WALR is negative due to snow redistribution/sublimation from wind scour events. Models also do not incorporate summer snowfall events, which significantly reduce melt; and summer wind events that, while rare, substantially reduce MB. Results are significant for the high Arctic where annual MB is relatively small, and minor changes in annual ablation/accumulation can significantly impact MB. Model parameterization sensitivity was determined using parameter values selected from field observations. Degree-day model (DDM) output is most sensitive to values of STLR and summer ALR, and the variable degree-day factor. These input parameters must therefore be verified by field measurements to increase confidence in model predictions. Perturbation of the DDM with global circulation model predictions of future (2000-2029) air temperature/precipitation show that increased air temperatures will have the greatest impact on net annual MB at JEG, and are hardly mitigated by a concurrent predicted winter precipitation increase. This results in enhanced melt/runoff production and superimposed ice formation, likely causing more extensive seasonal development of the glacier drainage system, and potentially impacting the dynamic response of JEG to climate change.

Boon, Sarah M. H.

77

Air temperature variability over three glaciers in the Ortles-Cevedale (Italian Alps): effects of glacier disintegration, intercomparison of calculation methods, and impacts on mass balance modeling  

NASA Astrophysics Data System (ADS)

Glacier mass balance models rely on accurate spatial calculation of input data, in particular air temperature. Lower temperatures (the so-called glacier cooling effect), and lower temperature variability (the so-called glacier damping effect) generally occur over glaciers, compared to ambient conditions. These effects, which depend on the geometric characteristics of glaciers and display a high spatial and temporal variability, have been mostly investigated on medium- to large-size glaciers so far, while observations on smaller ice bodies are scarce. Using a dataset from 8 on-glacier and 4 off-glacier weather stations, collected in summer 2010 and 2011, we analyzed the air temperature variability and wind regime over three different glaciers in the Ortles-Cevedale. The magnitude of the cooling effect and the occurrence of katabatic boundary layer (KBL) processes showed remarkable differences among the three ice bodies, suggesting the likely existence of important reinforcing mechanisms during glacier decay and disintegration. None of the methods proposed in the literature for calculating on-glacier temperature from off-glacier data fully reproduced our observations. Among them, the more physically-based procedure of Greuell and Bhm (1998) provided the best overall results where the KBL prevail, but it was not effective elsewhere (i.e. on smaller ice bodies and close to the glacier margins). The accuracy of air temperature estimations strongly impacted the results from a mass balance model which was applied to the three investigated glaciers. Most importantly, even small temperature deviations caused distortions in parameter calibration, thus compromising the model generalizability.

Carturan, L.; Cazorzi, F.; De Blasi, F.; Dalla Fontana, G.

2014-12-01

78

Mount Cheops Cirque Glacier: Response of a Small Debris Covered Glacier to Climate Change  

E-print Network

Mount Cheops Cirque Glacier: Response of a Small Debris Covered Glacier of a microclimate cirque glacier on Mount Cheops in Glacier National Park of Canada. Rapidly receding glaciers are becoming an important water resource concern

Smith, Dan

79

Mapping the Glaciers  

NSDL National Science Digital Library

This earth systems field lab begins with an in-class guided inquiry experience which uses Minnesota Geological Survey 3-D maps of the upper Midwest to determine where they believe glaciers may have had an influence. They will determine this by looking at landscapes and compiling their own evidence from the maps. They will also offer evidence for a hypothesis they generate which involves the direction that the glacier was traveling. The two-day lesson ends (after student presentations on their findings about glaciers) with a field investigation of one of our parking lot snow banks. Students will compare and contrast what they know about glaciers, with one of our parking lot snow banks, determining any similarities with how the landscape may have appeared during the Pleistocene.

80

Glossary of Glacier Terminology  

NSDL National Science Digital Library

This glossary provides definitions of terms necessary to understand the modern glacier environment. Terms are listed in alphabetical order and are accompanied by photographs. A separate section provides definitions of each type, accompanied by a photograph of an example.

81

Ablation of Martian glaciers  

NASA Technical Reports Server (NTRS)

Glacier like landforms are observed in the fretted terrain of Mars in the latitude belts near + or - 42 deg. It was suggested that sublimation or accumulation-ablation rates could be estimated for these glaciers if their shapes were known. To this end, photoclinometric profiles were obtained of a number of these landforms. On the basis of analyses of these profiles, it was concluded that ice is chiefly ablating from these landforms that either are inactive rock-glaciers or have materials within them that are moving exceedingly slowly at this time. These conclusions are consistent with other geologic information. The analyses were performed using a two-dimensional model of an isothermal glacier.

Moore, Henry J.; Davis, Philip A.

1987-01-01

82

Isotopic composition of ice cores and meltwater from upper fremont glacier and Galena Creek rock glacier, Wyoming  

USGS Publications Warehouse

Meltwater runoff from glaciers can result from various sources, including recent precipitation and melted glacial ice. Determining the origin of the meltwater from glaciers through isotopic analysis can provide information about such things as the character and distribution of ablation on glaciers. A 9.4 m ice core and meltwater were collected in 1995 and 1996 at the glacigenic Galena Creek rock glacier in Wyoming's Absaroka Mountains. Measurements of chlorine-36 (36Cl), tritium (3H), sulphur-35 (35S), and delta oxygen-18 (??18O) were compared to similar measurements from an ice core taken from the Upper Fremont Glacier in the Wind River Range of Wyoming collected in 1991-95. Meltwater samples from three sites on the rock glacier yielded 36Cl concentrations that ranged from 2.1 ?? 1.0 X 106 to 5.8??0.3 X 106 atoms/l. The ice-core 36Cl concentrations from Galena Creek ranged from 3.4??0.3 X 105 to 1.0??0.1 X 106 atoms/l. Analysis of an ice core from the Upper Fremont Glacier yielded 36Cl concentrations of 1.2??0.2 X 106 and 5.2??0.2 X 106 atoms/l for pre- 1940 ice and between 2 X 106 and 3 X 106 atoms/l for post-1980 ice. Purdue's PRIME Lab analyzed the ice from the Upper Fremont Glacier. The highest concentration of 36Cl in the ice was 77 ?? 2 X 106 atoms/l and was deposited during the peak of atmospheric nuclear weapons testing in the late 1950s. This is an order of magnitude greater than the largest measured concentration from both the Upper Fremont Glacier ice core that was not affected by weapons testing fallout and the ice core collected from the Galena Creek rock glacier. Tritium concentrations from the rock glacier ranged from 9.2??0.6 to 13.2??0.8 tritium units (TU) in the meltwater to -1.3??1.3 TU in the ice core. Concentrations of 3H in the Upper Fremont Glacier ice core ranged from 0 TU in the ice older than 50 years to 6-12 TU in the ice deposited in the last 10 years. The maximum 3H concentration in ice from the Upper Fremont Glacier deposited in the early 1960s during peak weapons testing fallout for this isotope was 360 TU. One meltwater sample from the rock glacier was analyzed for 35S with a measured concentration of 5.4??1.0 millibecquerel per liter (mBeq/l). Modern precipitation in the Rocky Mountains contains 35S from 10 to 40 mBeq/L. The ??18O results in meltwater from the Galena Creek rock glacier (-17.40??0.1 to -17.98??0.1 per mil) are similar to results for modern precipitation in the Rocky Mountains. Comparison of these isotopic concentrations from the two glaciers suggest that the meltwater at the Galena Creek site is composed mostly of melted snow and rain that percolates through the rock debris that covers the glacier. Additionally, this water from the rock debris is much younger (less than two years) than the reported age of about 2000 years for the subsurface ice at the mid-glacier coring site. Thus the meltwater from the Galena Creek rock glacier is composed primarily of melted surface snow and rain water rather than melted glacier ice, supporting previous estimates of slow ablation rates beneath the surface debris of the rock glacier.

DeWayne, Cecil L.; Green, J.R.; Vogt, S.; Michel, R.; Cottrell, G.

1998-01-01

83

A strategy for monitoring glaciers  

USGS Publications Warehouse

Glaciers are important features in the hydrologic cycle and affect the volume, variability, and water quality of runoff. Assessing and predicting the effect of glaciers on water resources require a monitoring program to provide basic data for this understanding. The monitoring program of the U.S. Geological Survey employs a nested approach whereby an intensively studied glacier is surrounded by less intensively studied glaciers and those monitored solely by remote sensing. Ideally, each glacierized region of the United States would have such a network of glaciers. The intensively studied glacier provides a detailed understanding of the physical processes and their temporal changes that control the mass exchange of the glaciers in that region. The less intensively studied glaciers are used to assess the variability of such processes within the region.

Fountain, Andrew G.; Krimmel, Robert M.; Trabant, Dennis C.

1997-01-01

84

Geological Field Trips: Glaciers  

NSDL National Science Digital Library

Students will utilize the Internet to take a virtual field trip to visit a glacier and discover what physical effects glaciers have on the land. They will also have the opportunity to virtually visit Vermont and trace the pictorial history of how a whale's fossils were found there. The site also contains a student worksheet for their visual field trip. The site also provides an explanation of the formation of fossils.

Patti Zvanut

2000-03-23

85

Variations in Sr and Nd isotopic ratios of cryoconite on glaciers in Asia, Alaska, and Greenland  

NASA Astrophysics Data System (ADS)

Recent shrinkages of glacial mass are not only due to global warming, but also possibly to accumulation of cryoconite on the glacial surface. Cryoconite is a biogenic surface dust consisting of organic matter mainly derived from living microbes on the glaciers, and mineral particles originated from basal till and/or wind-blown dust. Since cryoconite is dark color, it can reduce surface albedo of glaciers and accelerate their melting. Thus, it is important to understand their sources and formation process on the glaciers. The characteristics of cryoconite vary among geographical locations. For example, there are small amounts of cryoconite on Arctic glaciers and their glacial surface is clean. In contrast, large amounts of cryoconite accumulate on Asian glaciers and their glacial surface appears very dirty. These differences in cryoconite are likely to affect on surface albedo and melting of each glacier. However, the formation process of cryoconite, especially origins of minerals and production process of organic matters are still not well understood. Stable isotopic ratios of strontium (Sr) and neodymium (Nd) provide a means of identifying sources of substances and have been commonly used in loess or sediment studies. Furthermore, Sr isotope has been used as a tracer of Ca ion in studies of geochemical process, because its chemical characteristics are similar to Ca. Thus, Sr in organic matter including such organisms on the glacier may reveal their nutrient sources and ecology of them. In this study, we analyzed Sr and Nd isotopic ratios of four mineral and organic fractions in cryoconite on Asian and Polar glaciers. Based on the isotopic ratios, we identified origins of minerals in cryoconite and mineral sources used as nutrients by microbes on the glaciers. Sr and Nd isotopic ratios in the mineral fractions, especially silicate minerals, which are major components of mineral particles, vary significantly among the glaciers. Cryoconite on Asian glaciers showed higher Sr and lower Nd ratios in the north and also showed little variation within a glacier. On the other hand, those on Alaskan glacier showed lower Sr and large spatial variation in Nd on a glacier. Cryoconite on Greenlandic glaciers showed further high Sr and low Nd than the other glaciers. This suggests that origins of silicate minerals in cryoconite are substantially different among the glaciers. Compared with the isotopic ratios of silicate minerals in moraine, desert, and loess reported over the regions, those in cryoconite on Asian, Alaskan, and Greenlandic glaciers were close to those in respective regions. This result indicates that silicate minerals in cryoconite were derived from surrounding the glaciers. The Sr isotopic ratios of organic matter in cryoconite also varied among the glaciers. They may reflect the minerals used by glacial microbes as nutrients.

Nagatsuka, N.; Takeuchi, N.; Nakano, T.

2012-12-01

86

Getting the Shot, Grinnell Glacier, Glacier National Park.  

USGS Multimedia Gallery

USGS scientist shoots a repeat photograph of Grinnell Glacier in Glacier National Park to illustrate glacial recession due to impacts of climate change. *note ? logo on scientists hat is logo from USGS Northern Rocky Mountain Science Center, not private....

87

Getting the Shot, Grinnell Glacier, Glacier National Park.  

USGS Multimedia Gallery

USGS scientist shoots a repeat photograph of Grinnell Glacier in Glacier National Park to illustrate glacial recession due to impacts of climate change. *note logo on scientists hat is logo from USGS Northern Rocky Mountain Science Center, not private....

88

Exploring the links between transient water inputs and glacier velocity in a small temperate glacier in southeastern Alaska  

NASA Astrophysics Data System (ADS)

Glaciers along the Gulf of Alaska are thinning and retreating rapidly. An important control on the rate at which ice is being lost is basal motion because higher glacier velocities increase the rate at which ice is delivered to ablation zones. Recent research has focused on understanding the effects of sub-glacial water storage on glacier basal motion. In this study, we examined two seasons of the effect of hydrologic controls (from large rainfall events as well as a glacier lake outburst floods) on the velocity of the Lemon Creek Glacier in southeastern Alaska. Lemon Creek Glacier is a moderately sized (~16~km2) temperate glacier at the margin of the Juneau Icefield. An ice-marginal lake forms at the head of the glacier and catastrophically drains once or twice every melt season. We have instrumented the glacier with two meteorological stations: one at the head of the glacier near the ice-marginal lake and another several kilometers below the terminus. These stations measure temperature, relative humidity, precipitation, incoming solar radiation and wind speed and direction. Lake stage in the ice-marginal lake was monitored with a pressure transducer. In addition, Lemon Creek was instrumented with a water quality sonde at the location of a US Geological Survey gaging station approximately 3 km downstream from the glacier terminus. The sonde provides continuous measurements of water temperature, dissolved oxygen, turbidity and conductivity. Finally, multiple Trimble NetRS dual frequency, differential GPS units were deployed on the glacier along the centerline of the glacier. All of the instruments were run continuously from May-September 2008 and May-September 2009 and captured threee outburst floods associated with the ice-marginal lake drainage as well as several large (>3~cm) rainfall events associated with frontal storms off of the Gulf of Alaska in late summer. Taken together, these data allow us to test the hypothesis that water inputs which overwhelm subglacial drainage networks result in increased rates of basal motion. 2008 was an extremely rainy summer, and the (single) lake drainage occurred during the largest precipitation even of the summer. 2009 on the other hand, was comparatively dry and sunny for the majority of the summer--the first lake drainage occurred during a several day stretch of sunny weather. The lake refilled during an extreme rainfall (20 cm of rain was recorded in a 24 hour period at a met station 16 km away and about 500 m lower in elevation) and then subsequently drained during a rainy period. We focus on the comparison of the data from two years, including the glacial response to the lake drainage with and without accompanying precipitation inputs.

Heavner, M.; Habermann, M.; Hood, E. W.; Fatland, D. R.

2009-12-01

89

Exploring the links between transient water inputs and glacier velocity in a small temperate glacier in southeastern Alaska  

NASA Astrophysics Data System (ADS)

Glaciers along the Gulf of Alaska are thinning and retreating rapidly and over the last century this loss of ice has contributed measurably to global sea level rise. An important control on the rate at which ice is being lost is basal motion because higher glacier velocities increase the rate at which ice is delivered to ablation zones. Recent research has focused on understanding the effects of sub-glacial water storage on glacier basal motion. In this study, we examined how water inputs from large rainfall events as well as a glacier lake outburst flood affected the velocity of the Lemon Creek Glacier in southeastern Alaska. Lemon Creek Glacier is a moderately sized (~16~km2) temperate glacier at the margin of the Juneau Icefield. An ice- marginal lake forms at the head of the glacier and catastrophically drains once or twice every melt season. We have instrumented the glacier with two meteorological stations: one at the head of the glacier near the ice-marginal lake and another several kilometers below the terminus. These stations measure temperature, relative humidity, precipitation, incoming solar radiation and wind speed and direction. Lake stage in the ice- marginal lake was monitored with a pressure transducer. In addition, Lemon Creek was instrumented with a water quality sonde at the location of a US Geological Survey gaging station approximately 3 km downstream from the glacier terminus. The sonde provides continuous measurements of water temperature, dissolved oxygen, turbidity and conductivity. Finally, two Trimble NetRS dual frequency, differential GPS units were deployed on the glacier at approximately 1/3 and 2/3 down the centerline of the glacier. All of the instruments were run continuously from May-September 2008 and captured the outburst flood associated with the ice-marginal lake drainage as well as several large (>3~cm) rainfall events associated with frontal storms off of the Gulf of Alaska in late summer. Taken together, these data allow us to test the hypothesis that water inputs which overwhelm subglacial drainage networks result in increased rates of basal motion.

Habermann, M.; Hood, E.; Heavner, M.; Motyka, R.

2008-12-01

90

Debris-Free Plateau Glacier  

USGS Multimedia Gallery

Small debris-free plateau glacier with glacier lakes at Gangrinchemzoe Pass at 5,200 m, south of the main Himalayan divide, Bhutan. Image courtesy of Shuji Iwata, Tokyo Metropolitan University, Japan....

91

The GLIMS Glacier Database  

NASA Astrophysics Data System (ADS)

The Global Land Ice Measurements from Space (GLIMS) project has built a geospatial and temporal database of glacier data, composed of glacier outlines and various scalar attributes. These data are being derived primarily from satellite imagery, such as from ASTER and Landsat. Each "snapshot" of a glacier is from a specific time, and the database is designed to store multiple snapshots representative of different times. We have implemented two web-based interfaces to the database; one enables exploration of the data via interactive maps (web map server), while the other allows searches based on text-field constraints. The web map server is an Open Geospatial Consortium (OGC) compliant Web Map Server (WMS) and Web Feature Server (WFS). This means that other web sites can display glacier layers from our site over the Internet, or retrieve glacier features in vector format. All components of the system are implemented using Open Source software: Linux, PostgreSQL, PostGIS (geospatial extensions to the database), MapServer (WMS and WFS), and several supporting components such as Proj.4 (a geographic projection library) and PHP. These tools are robust and provide a flexible and powerful framework for web mapping applications. As a service to the GLIMS community, the database contains metadata on all ASTER imagery acquired over glacierized terrain. Reduced-resolution of the images (browse imagery) can be viewed either as a layer in the MapServer application, or overlaid on the virtual globe within Google Earth. The interactive map application allows the user to constrain by time what data appear on the map. For example, ASTER or glacier outlines from 2002 only, or from Autumn in any year, can be displayed. The system allows users to download their selected glacier data in a choice of formats. The results of a query based on spatial selection (using a mouse) or text-field constraints can be downloaded in any of these formats: ESRI shapefiles, KML (Google Earth), MapInfo, GML (Geography Markup Language) and GMT (Generic Mapping Tools). This "clip-and-ship" function allows users to download only the data they are interested in. Our flexible web interfaces to the database, which includes various support layers (e.g. a layer to help collaborators identify satellite imagery over their region of expertise) will facilitate enhanced analysis to be undertaken on glacier systems, their distribution, and their impacts on other Earth systems.

Raup, B. H.; Khalsa, S. S.; Armstrong, R.

2007-12-01

92

Jakobshavn Glacier Retreat (WMS)  

NSDL National Science Digital Library

Since measurements of Jakobshavn Isbrae were first taken in 1850, the glacier has gradually receded, finally coming to rest at a certain point for the past 5 decades. However, from 1997 to 2003, the glacier has begun to recede again, this time almost doubling in speed. The finding is important for many reasons. For starters, as more ice moves from glaciers on land into the ocean, it raises sea levels. Jakobshavn Isbrae is Greenlands largest outlet glacier, draining 6.5 percent of Greenlands ice sheet area. The ice streams speed-up and near-doubling of ice flow from land into the ocean has increased the rate of sea level rise by about .06 millimeters (about .002 inches) per year, or roughly 4 percent of the 20th century rate of sea level increase. This animation shows the recession for three years, from 2001 through 2003. The line of recession shows the place where the glacier meets the ocean and where pieces calve off and flow away from land toward open water.

Eric Sokolowsky

2005-03-30

93

1, 1739, 2007 Glacier balance  

E-print Network

TCD 1, 17­39, 2007 Glacier balance measurement, forecasting M. S. Pelto Title Page Abstract The Cryosphere Discussions is the access reviewed discussion forum of The Cryosphere Glacier annual balance: 18 June 2007 Correspondence to: M. S. Pelto (mspelto@nichols.edu) 17 #12;TCD 1, 17­39, 2007 Glacier

Paris-Sud XI, Université de

94

Engineering geomorphology of rock glaciers  

NASA Astrophysics Data System (ADS)

A partnership between geomorphology and engineering is facilitating human development in this harsh environment. Rock glaciers provide locations for urban water sources, construction borrow sources, drill sites, shaft and tunnel portals, ski tower supports, and dam abutments. Rock glaciers, as dynamic landforms, necessitate proper identification in the field. Placing structures on, in, or adjacent to rock glaciers requires an appreciation and understanding of their temporal stability. Internal and surface characteristics provide important clues to the development and deformation of rock glaciers. Rock glaciers play a significant role in the alpine debris transport system. Active movement and mass wasting are perhaps the most obvious geologic hazards affecting engineered works. The structure of the rock glacier is conducive to the production of a steady, continuous supply of meltwater during summer months. Thus, rock glaciers serve as alpine aquifers. Consideration of rock glaciers as potential aquifer sources requires caution because of the long-term impact of climate change on the temporal nature of the landform. From the rock glaciers that we have monitored for water quality characteristics, it appears that they provide quality potable water. This paper provides a foundation for appreciation and understanding of rock glaciers from an engineering geomorphologic point of view. The approach taken in this paper provides practical, important information to aid the engineer and engineering geologist in prudent evaluations of rock glaciers as potential sites for human development and uses. The bottom line of our paper is: rock glaciers must be avoided for essentially all structures.

Burger, K. C.; Degenhardt, J. J.; Giardino, J. R.

1999-12-01

95

Denali Fault: Black Rapids Glacier  

USGS Multimedia Gallery

View eastward along Black Rapids Glacier. The Denali fault follows the trace of the glacier. These very large rockslides went a mile across the glacier on the right side. Investigations of the headwall of the middle landslide indicate a volume at least as large as that which fell, has dropped a mete...

96

Iceland Glacier Recession 1973 to 2000, Glacier Terminus contrast emphasized  

NSDL National Science Digital Library

This animation shows glacier recesion at the Breidamerkurjokull glacier in Iceland. The data from 1973 is taken from Landsat 1 and the 2000 data is from Landsat 7. The Breidamerkurjokull glacier in Iceland has been measured by Landsat to be receding since 1973. The glacierologists in Iceland and here at Nasas Goddard Space Flight Center have measured the recession throughout the entire glacier and found different rates of recession in different areas. In genral, the glacier seems to be receding at about 2% annually. It is extremely controversial whether this recession is caused by global warming.

Lori Perkins

2001-04-09

97

Karakoram glacier surge dynamics  

NASA Astrophysics Data System (ADS)

We examine the surges of five glaciers in the Pakistan Karakoram using satellite remote sensing to investigate the dynamic nature of surges in this region and how they may be affected by climate. Surface velocity maps derived by feature-tracking quantify the surge development spatially in relation to the terminus position, and temporally with reference to seasonal weather. We find that the season of surge initiation varies, that each surge develops gradually over several years, and that maximum velocities are recorded within the lowermost 10 km of the glacier. Measured peak surge velocities are between one and two orders of magnitude greater than during quiescence. We also note that two of the glaciers are of a type not previously reported to surge. The evidence points towards recent Karakoram surges being controlled by thermal rather than hydrological conditions, coinciding with high-altitude warming from long-term precipitation and accumulation patterns.

Quincey, D. J.; Braun, M.; Glasser, N. F.; Bishop, M. P.; Hewitt, K.; Luckman, A.

2011-09-01

98

Climate regime of Asian glaciers revealed by GAMDAM Glacier Inventory  

NASA Astrophysics Data System (ADS)

Among meteorological elements, precipitation has a large spatial variability and less observation, particularly in High Mountain Asia, although precipitation in mountains is an important parameter for hydrological circulation. We estimated precipitation contributing to glacier mass at median elevation of glaciers, which is presumed to be at equilibrium-line altitude (ELA) so that mass balance is zero at that elevation, by tuning adjustment parameters of precipitation. We also made comparisons between median elevation of glaciers, including the effect of drifting snow and avalanche, and eliminated those local effects. Then, we could obtain median elevation of glaciers depending only on climate to estimate glacier surface precipitation. The calculated precipitation contributing to glacier mass can elucidate that glaciers in the arid High Mountain Asia have very less precipitation, while much precipitation contribute to glacier mass in the Hindu Kush, the Himalayas, and the Hengduan Shan due to not only direct precipitation amount but also avalanche nourishment. We classified glaciers in High Mountain Asia into summer-accumulation type and winter-accumulation type using the summer accumulation ratio, and confirmed that summer-accumulation type glaciers have a higher sensitivity than winter-accumulation type glaciers.

Sakai, A.; Nuimura, T.; Fujita, K.; Takenaka, S.; Nagai, H.; Lamsal, D.

2014-07-01

99

Greenland Glacier Albedo Variability  

NASA Technical Reports Server (NTRS)

The program for Arctic Regional Climate Assessment (PARCA) is a NASA-funded project with the prime goal of addressing the mass balance of the Greenland ice sheet. Since the formal initiation of the program in 1995, there has been a significant improvement in the estimates of the mass balance of the ice sheet. Results from this program reveal that the high-elevation regions of the ice sheet are approximately in balance, but the margins are thinning. Laser surveys reveal significant thinning along 70 percent of the ice sheet periphery below 2000 m elevations, and in at least one outlet glacier, Kangerdlugssuaq in southeast Greenland, thinning has been as much as 10 m/yr. This study examines the albedo variability in four outlet glaciers to help separate out the relative contributions of surface melting versus ice dynamics to the recent mass balance changes. Analysis of AVHRR Polar Pathfinder albedo shows that at the Petermann and Jakobshavn glaciers, there has been a negative trend in albedo at the glacier terminus from 1981 to 2000, whereas the Stor+strommen and Kangerdlugssuaq glaciers show slightly positive trends in albedo. These findings are consistent with recent observations of melt extent from passive microwave data which show more melt on the western side of Greenland and slightly less on the eastern side. Significance of albedo trends will depend on where and when the albedo changes occur. Since the majority of surface melt occurs in the shallow sloping western margin of the ice sheet where the shortwave radiation dominates the energy balance in summer (e.g. Jakobshavn region) this region will be more sensitive to changes in albedo than in regions where this is not the case. Near the Jakobshavn glacier, even larger changes in albedo have been observed, with decreases as much as 20 percent per decade.

2004-01-01

100

Northern Illinois University: Glaciers  

NSDL National Science Digital Library

Northern Illinois University offers illustrative summary of glaciers and glacial processes. The website provides a timeline of the glacial advances into Illinois. Students and educators can learn a few of the landscape features that scientists use to interpret geologic history. Users can learn how glaciers affected Illinois's topography and waterbodies. The site furnishes educational maps of Illinois's bedrock geology and shaded relief. The text is linked to a glossary to assist users with glacial terminology. While this website does concentrate on the state of Illinois, everyone can learn basic characteristics of glacial movements.

101

Svalbard surging glacier landsystems  

NASA Astrophysics Data System (ADS)

The percentage of Svalbard glaciers thought to be of surge-type is somewhere between 13-90% according to different sources variously based on statistical analysis and observations of diagnostic glaciological and geomorphological features, e.g. looped moraines. Developing a better understanding of which of these figures, if either, is most realistic is important in the context of glacier dynamics and related contributions of small glaciers and ice caps to sea level change in the immediate future. We present detailed geomorphological assessments of the margins of several known surge-type glaciers in Svalbard in order to update and improve the existing framework by which they are identified, and to provide a foundation for future reassessments of the surge-type glacier population based on distinct landform-sediment assemblages. Three landsystems are proposed: (1) Surges of small valley glaciers produce a prominent ice-cored latero-frontal moraine at their surge maximum and are characterised by an inner zone of ice stagnation terrain (hummocky topography, kettle lakes, debris flows) with no or only very few poorly-defined bedforms (crevasse squeeze ridges, eskers and flutes) and no recessional moraines. Many of these glaciers may have surged in the past but show no signs that they have the capability to do so again in the future. (2) Larger land-terminating glaciers, often with several tributaries, typically produce a push moraine complex which contains evidence for multiple advances, as identified from ridge-meltwater channel relationships. The inner zone often contains a large lagoon, partly dammed by the push moraine complex, and widespread ice stagnation terrain. Crevasse squeeze ridges, eskers and flutes are well-defined but small and limited in number and distribution. (3) Surges of large tidewater glaciers produce distinctive, often multi-generational, landform assemblages both in submarine and lateral terrestrial positions. The well-preserved submarine record is characterised by large cross-fjord push moraines of fjord floor sediments with lobe-shaped debris flows on their distal slope, glacial lineations, dense rhombohedral networks of crevasse squeeze ridges, and eskers. Annual push moraines associated with the quiescent phase are also observed and are unique to the submarine record. The terrestrial record consists of large lateral moraine systems alongside the fjord which contain outer push ridges composed of shallow marine sediments and an inner zone of ice stagnation terrain. Eskers, flutes and large, sharp-crested crevasse fill ridges in dense networks are superimposed on this inner zone; the latter are similar in character to their submarine counterparts but typically higher. We suggest that these three landsystems broadly characterise the geomorphology of the vast majority of known Svalbard surge-type glaciers and may allow previously unknown surge-type glaciers to be identified, both in the field and from aerial photographs and sea floor imagery.

Lovell, Harold; Benn, Douglas; Lukas, Sven; Flink, Anne

2014-05-01

102

Winds  

NSDL National Science Digital Library

In this problem-based learning (PBL) scenario, students prepare a presentation for investors showing how their fishing company has a significant advantage because it locates upwelling zones and fishing areas using TRMM (Tropical Rainfall Measuring Mission) and other satellite data. Prior to launching the PBL, students learn about wind: the topics of air pressure, coriolis effect, upwelling and the role of differential heating on the atmosphere are explored in classroom demonstrations. Materials required include a beaker, coffee grounds, drinking straw, balloon, flashlight, and turntable. The resource includes teacher background information, glossary, assessment rubric, and an appendix introducing problem-based learning.

2012-08-03

103

Melting Glaciers Threaten Peru  

NSDL National Science Digital Library

Thousands of people in the Andes mountains of Peru are having their lives affected in both a practical and cultural way by climate change, which is causing the region's glaciers to melt. This document explores the causes of the glacial melt and its impacts on the local cultures.

2003-10-09

104

Taking a Glacier's Pulse  

NSDL National Science Digital Library

This article profiles Dr. Leigh Stearns, a research scientist with the National Science Foundation's Science and Technology Center for Remote Sensing of Ice Sheets (CReSIS) and Assistant Professor in Geology at the University of Kansas who studies glaciers in Greenland.

Carol Landis

105

Glaciers and Glaciation  

NSDL National Science Digital Library

This web page contains 23 multiple-choice practice exam questions on the topic glaciers and glaciation. It is part of the Principles of Earth Science course at the University of South Dakota. Users select an answer, then click to see if it is correct.

Timothy Heaton

106

Gifts of the Glaciers  

NSDL National Science Digital Library

This website highlights the glacial formation of the Great Lakes: - Lake Superior, Lake Huron, Lake Michigan, Lake Erie and Lake Ontario. This site provides photos and descriptions of the lakes and how they formed by the glaciers thousands of years ago.

Stephen Wittman

107

Changing Planet: Melting Glaciers  

NSDL National Science Digital Library

This NBC Learn video features climate scientists doing their research on Mt. Kilimanjaro to study the climate of the past. The scientists put the recently observed changes on the glacier into perspective by comparing past climate fluctuations, stressing that the current observed rate of change is unprecedented.

NBC Learn video - Changing Planet

108

Glaciers and Glaciation  

NSDL National Science Digital Library

This site contains lecture notes to accompany one chapter/lecture of a physical geology course using the text, The Dynamic Earth: An Introduction to Physical Geology, 4th Edition, by Brian J. Skinner and Stephen C. Porter. Subtopics include glaciers, glacial deposits, glacial features, glaciation, and glacial ages.

Stephen Nelson

109

Assessing glacier response to changing climate using new and historical field observations on the Kahiltna Glacier in the Central Alaska Range  

NASA Astrophysics Data System (ADS)

Like many remote mountain ranges in Alaska, British Columbia and the Yukon, the Central Alaska Range is a highly glaciated but relatively sparsely monitored region in terms of glacier mass balance and meteorological ground measurements. To date, long-term trends and balance gradients are poorly known, though these are of particular importance for calibrating melt models and evaluating remote sensing techniques aimed at assessing glacier response to climate change. Among the best field-based data available for the region are approximately 20 years of National Park Service mass balance measurements on the Kahiltna Glacier. A land-terminating valley glacier with a wide range of altitudes and non-surge-type behavior, the Kahiltna Glacier is often taken as a benchmark for the current mass balance state of Central Alaska Range glaciers. However, mass balance has historically only been sampled at a single location on the glacier, allowing for the possibility of substantial scaling error when these findings are extrapolated spatially. Here we present an extended campaign of field-based observations on the Kahiltna Glacier in 2010 and 2011, used to expand data from the single National Park Service index site to the entire glacier in order to reconstruct the historical mass balance record. Measurements include summer melt at 13 ablation stake positions, winter accumulation surveys along a centerline and several lateral profiles, summer temperatures at five elevations, and meteorological variables such as incoming/reflected solar radiation and wind speed/direction at a representative ablation area site. Calibrated against the observed temperature gradients, a set of modeling tools has been developed for the glacier using a fully distributed positive degree day approach. Derived mass change estimates provide key information for assessing the little known state of health of Central Alaska Range glaciers. By serving as a template, balance and temperature gradients observed on the Kahiltna Glacier can enable mass balance estimates for other glaciers in the region with as little as a single stake measurement. Moreover, mass changes derived from this study will provide seasonal corrections to remote sensing estimates from repeat laser altimetry, and will assist in calibrating regionally downscaled GRACE gravimetry measurements. Ultimately, this research hopes to provide crucial information for determining past and current glacier melt evolution for the Kahiltna Glacier and Central Alaska Range glaciers as a whole.

Young, J. C.; Arendt, A. A.

2011-12-01

110

Alaskan Glaciers and Glacier-Outburst Floods (Jkulhlaups)  

NASA Astrophysics Data System (ADS)

Alaska has more than 50,000 glaciers, including about 2,000 valley glaciers. Nearly all Alaskan glaciers are temperate. Many Alaskan valley glaciers end in ice-marginal lakes formed by terminal or recessional moraines. Some Alaskan valley glaciers act as ice dams, forming lakes by blocking side valleys or by extending into adjacent valleys. Many Alaskan glaciers store large quantities of water in thermokarst lakes, crevasses, conduits, and cavities. Annually, all of these situations result in jkulhlaups. Draining of ice-dammed lakes or ice-marginal lakes causes most. Some jkulhlaups are produced by the release of water stored subglacially, englacially, or supraglacially, sometimes through surge-related processes. Less frequently, jkulhlaups result from the melting of glaciers located around the summit craters of many of Alaska's erupting volcanoes. Recently, all of these mechanisms have produced jkulhlaups that have effected resource development, fisheries, and infrastructure. In spite of Alaska's small population and large geographic area, annually Alaskan jkulhlaups cause millions of dollars of damage. In the last three decades, jkulhlaup events at Hubbard Glacier have produced two of the largest floods that have occurred anywhere on Earth in post-Pleistocene time. Two recent Bering Glacier jkulhlaups resulted in a flood lasting nearly a year and in the rapid lowering of an ice-dammed lake by more than 50 m. This presentation characterizes the scope of jkulhlaups that have recently occurred in Alaska, focusing on recent jkulhlaup events at Hubbard and Bering Glaciers and Mount Redoubt.

Molnia, B. F.

2009-04-01

111

Gifts of the Glaciers Glacial Landforms  

E-print Network

Gifts of the Glaciers Glacial Landforms Gifts of the Glaciers Moving ice of glacier was responsible. Glaciers perform, in many ways, like an excavator. Although they can push weak material, like gravel, like it in place, like a ripper. And, like a bulldozer, glaciers are poor at eroding rock unless it is already

Cochran-Stafira, D. Liane

112

Glacier Recession Prepared by Joni L. Kincaid  

E-print Network

Glacier Recession Prepared by Joni L. Kincaid for the Advancing Geospatial Skills in Science funded by the National Science Foundation's GK-12 Program. Spring, 2007 #12;Glacier: a large mass of ice Line Glacier How do glaciers form? Glaciers form in locations where the snow does not melt over

113

On the instability of avalanching glaciers  

Microsoft Academic Search

The instability of hanging glaciers and more generally of avalanching glaciers is discussed on the basis of observations performed on several glaciers located in the European Alps. A classification of avalanching glaciers is proposed, which allows a primary appreciation of the danger inherent in these glaciers. On the basis of field observations and results of numerical simulations of crevassing, the

Antoine Pralong; Martin Funk

2006-01-01

114

Annual satellite imaging of the world's glaciers Assessment of glacier extent and change  

E-print Network

GLIMS HIGH ICE Annual satellite imaging of the world's glaciers Assessment of glacier extent and change Development and population of a digital glacier data inventory #12;Glaciers of High Asia: Where was a debris-covered glacier near Mt. Everest J.S. Kargel, April 2001 #12;Gangotri Glacier, India #12;A. Kääb

115

Observed changes in glaciers in China  

NASA Astrophysics Data System (ADS)

Small glaciers are highly sensitive to changes in temperature and precipitation making them important indicators of regional climate change. At present, worldwide evaluation and prediction of glacier change are based on or aided by detailed observations from a small number of glaciers due to the inaccessibility of many glacier areas. Thus, the ground-based detailed glacier monitoring is of strong need and extremely important for glacier variability evaluation in both regional and global scale. China has 46,377 glaciers with a total area of 59,425 km2 and 5600 km3 in volume. Most of the glaciers have experienced rapid and accelerated shrinkage during last few decades. Although some of the glaciers have been investigated or observed through field expeditions and ground-based monitoring, the information of the glacier changes are poorly documented and relatively new to international community. This paper summarizes the observed changes of 9 reference glaciers in China: 1) Urumqi Glacier No. 1, located at the headwaters of Urumqi River in eastern Tianshan which is the best observed glacier in China; 2) Haxilegen Glacier No. 51, at Kuitun River in eastern Tianshan; 3) Qingbingtan Glacier No.72, located at the upper reach of Aksu River in the middle of Tianshan; 4) Miaoergou ice cap, located in the most east part of Tianshan; 5) Laohugou Glacier No. 12, located in Shule River in Qinlian Mountains; 6) Qi Yi glacier (also named as July First Glacier), located in Qinlian Mountains; 7) Dongkemadi Glacier located in Tianggula Mountains in Qinghai-Xizang (Tibetan) Plateau; 8) Rongbu Glacier at the north slop of Mt. Everest in Himalaya Mountains; and 9) Baishui Glacier No. 1, the only temperate glacier in this glacier group, located at Yulong Snow Mountain. Geographically those reference glaciers well represent the glaciers in the major high mountain system in western China. In addition, they have been monitored for 5-53 years and promise the best datasets for glacier changes in their regions.

Li, L.; Li, H.; Wang, F.

2012-04-01

116

100 Years of Glacier Retreat in Central Asia  

E-print Network

100 Years of Glacier Retreat in Central Asia 100 Years of Glacier Retreat in Central Asia · Jeffrey+GLIMS Glacier databaseMODIS+GLIMS Glacier database #12;Benchmark GlaciersBenchmark Glaciers #12;Everest ASTER Mosaic, 2001Everest ASTER Mosaic, 2001 #12;KhumbuKhumbu Glacier, Nepal, 1958Glacier, Nepal, 1958 #12

117

Modeled Climate-Induced Glacier Change in Glacier National Park, 1850-2100  

NSDL National Science Digital Library

This animated model shows the predicted effects of glacial melting and changes in vegetation patterns in the Blackfoot-Jackson Glacier Basin of Glacier National Park, Montana. The scenario incorporated in the model consists of a predicted exponential rise in atmospheric CO2 concentrations, a 2xCO2 global warming scenario, with a concurrent warming of 2-3 degrees centigrade (4-5 degrees Fahrenheit) by the year 2050. In addition, it assumes that precipitation, primarily in the form of rain, will increase over the same time period about 10 percent. The animation is accompanied by a set of still images displaying intermediate steps used in the calculations of the ecological components, such as terrain characteristics, sun impact, soil moisture, and wind.

Dan Fagre

2003-01-01

118

Life Cycle of a Glacier  

NSDL National Science Digital Library

This slide show follows a snowflake through its life in a glacier. The path of the ice crystal is traced from its incorporation in the zone of accumulation, through the zone of ablation to its final departure, whether being calved as an iceberg or melting or sublimated. There is also information on the speed of the glacier and the difference between a cold and a warm glacier.

119

Glacier National Park  

NSDL National Science Digital Library

This is the homepage of Glacier National Park. Users can access materials on the park's ecology and environment (plants and animals, biodiversity and air quality, geology, and fires), the culture and history of the park, park activities, and publications on naturalist activities. There are also video clips of park wildlife and scenery, a photo gallery, and live webcams. Links are provided to additional information, such as research activities on bear DNA and global climate change.

120

Modeled and measured glacier change and related glaciological, hydrological, and meteorological conditions at South Cascade Glacier, Washington, balance and water years 2006 and 2007  

USGS Publications Warehouse

Winter snow accumulation and summer snow and ice ablation were measured at South Cascade Glacier, Washington, to estimate glacier mass balance quantities for balance years 2006 and 2007. Mass balances were computed with assistance from a new model that was based on the works of other glacier researchers. The model, which was developed for mass balance practitioners, coupled selected meteorological and glaciological data to systematically estimate daily mass balance at selected glacier sites. The North Cascade Range in the vicinity of South Cascade Glacier accumulated approximately average to above average winter snow packs during 2006 and 2007. Correspondingly, the balance years 2006 and 2007 maximum winter snow mass balances of South Cascade Glacier, 2.61 and 3.41 meters water equivalent, respectively, were approximately equal to or more positive (larger) than the average of such balances since 1959. The 2006 glacier summer balance, -4.20 meters water equivalent, was among the four most negative since 1959. The 2007 glacier summer balance, -3.63 meters water equivalent, was among the 14 most negative since 1959. The glacier continued to lose mass during 2006 and 2007, as it commonly has since 1953, but the loss was much smaller during 2007 than during 2006. The 2006 glacier net balance, -1.59 meters water equivalent, was 1.02 meters water equivalent more negative (smaller) than the average during 1953-2005. The 2007 glacier net balance, -0.22 meters water equivalent, was 0.37 meters water equivalent less negative (larger) than the average during 1953-2006. The 2006 accumulation area ratio was less than 0.10, owing to isolated patches of accumulated snow that endured the 2006 summer season. The 2006 equilibrium line altitude was higher than the glacier. The 2007 accumulation area ratio and equilibrium line altitude were 0.60 and 1,880 meters, respectively. Accompanying the glacier mass losses were retreat of the terminus and reduction of total glacier area. The terminus retreated at a rate of about 13 meters per year during balance year 2006 and at a rate of about 8 meters per year during balance year 2007. Glacier area near the end of balance years 2006 and 2007 was 1.74 and 1.73 square kilometers, respectively. Runoff from the basin containing the glacier and from an adjacent nonglacierized basin was gaged during all or parts of water years 2006 and 2007. Air temperature, wind speed, precipitation, and incoming solar radiation were measured at selected locations on and near the glacier. Air-temperature over the glacier at a height of 2 meters generally was less than at the same altitude in the air mass away from the glacier. Cooling of the air by the glacier increased systematically with increasing ambient air temperature. Empirically based equations were developed to estimate 2-meter-height air temperature over the glacier at five sites from site altitude and temperature at a non-glacier reference site.

Bidlake, William R.; Josberger, Edward G.; Savoca, Mark E.

2010-01-01

121

Mass balance model parameter transferability on a tropical glacier  

NASA Astrophysics Data System (ADS)

The mass balance and melt water production of glaciers is of particular interest in the Peruvian Andes where glacier melt water has markedly increased water supply during the pronounced dry seasons in recent decades. However, the melt water contribution from glaciers is projected to decrease with appreciable negative impacts on the local society within the coming decades. Understanding mass balance processes on tropical glaciers is a prerequisite for modeling present and future glacier runoff. As a first step towards this aim we applied a process-based surface mass balance model in order to calculate observed ablation at two stakes in the ablation zone of Shallap Glacier (4800 m a.s.l., 9S) in the Cordillera Blanca, Peru. Under the tropical climate, the snow line migrates very frequently across most of the ablation zone all year round causing large temporal and spatial variations of glacier surface conditions and related ablation. Consequently, pronounced differences between the two chosen stakes and the two years were observed. Hourly records of temperature, humidity, wind speed, short wave incoming radiation, and precipitation are available from an automatic weather station (AWS) on the moraine near the glacier for the hydrological years 2006/07 and 2007/08 while stake readings are available at intervals of between 14 to 64 days. To optimize model parameters, we used 1000 model simulations in which the most sensitive model parameters were varied randomly within their physically meaningful ranges. The modeled surface height change was evaluated against the two stake locations in the lower ablation zone (SH11, 4760m) and in the upper ablation zone (SH22, 4816m), respectively. The optimal parameter set for each point achieved good model skill but if we transfer the best parameter combination from one stake site to the other stake site model errors increases significantly. The same happens if we optimize the model parameters for each year individually and transfer these combinations to the other year. We show that multi-site and multi-year analyses are crucial before extrapolating ablation modeling to larger glacier areas. So far tested surface albedo schemes and respective parameterizations can obviously not satisfyingly reproduce the dynamics of glacier surface conditions at our study site and new solutions to the problem have to be explored.

Gurgiser, Wolfgang; Mlg, Thomas; Nicholson, Lindsey; Kaser, Georg

2013-04-01

122

Muir Glacier in Glacier Bay National Monument 2004  

USGS Multimedia Gallery

This August 2004 photo further documents the significant changes that have occurred during the 63 years between photographs A and C, and during the 54 years between photographs B and C. Muir Glacier has retreated out of the field of view and is now nearly 5 miles to the northwest. Riggs Glacier has ...

123

Listening to Glaciers: Passive hydroacoustics near marine-terminating glaciers  

USGS Publications Warehouse

The catastrophic breakup of the Larsen B Ice Shelf in the Weddell Sea in 2002 paints a vivid portrait of the effects of glacier-climate interactions. This event, along with other unexpected episodes of rapid mass loss from marine-terminating glaciers (i.e., tidewater glaciers, outlet glaciers, ice streams, ice shelves) sparked intensified study of the boundaries where marine-terminating glaciers interact with the ocean. These dynamic and dangerous boundaries require creative methods of observation and measurement. Toward this effort, we take advantage of the exceptional sound-propagating properties of seawater to record and interpret sounds generated at these glacial ice-ocean boundaries from distances safe for instrument deployment and operation.

Pettit, E.C.; Nystuen, J.A.; O'Neel, Shad

2012-01-01

124

Glaciers and the Changing Earth  

NSDL National Science Digital Library

In this lesson, students will investigate how glaciers affect the landscape in the context of wondering how the rocks used in the stone walls first got into the ground. Following a directed reading and discussion, they will perform an activity in which they use ice cubes and a bucket of sand to simulate the effects of a glacier.

125

Chernobyl fallout on Alpine glaciers  

SciTech Connect

Measurements of the gross beta activity of snow samples from four Alpine glaciers contaminated by radioactive fallout from the Chernobyl nuclear accident and a gamma-spectrum analysis of selected samples are reported. The results are discussed with respect to possible risks to the population from using meltwater from these glaciers as drinking water.

Ambach, W.; Rehwald, W.; Blumthaler, M.; Eisner, H.; Brunner, P.

1989-01-01

126

Life Cycle of a Glacier  

NSDL National Science Digital Library

An interactive slide show explores the journey of a single snowflake onto and through a glacier. This journey, which can take as much as 30,000 years to complete, shows that the life cycle of a glacier can be more complex than originally perceived.

127

ASTER Image of Gangotri Glacier  

USGS Multimedia Gallery

Sept 9, 2001 ASTER image showing the position of the terminus of Gangotri Glacier, India, between 1780 and 2001. Image from Jesse Allen, NASA's Earth Observatory. Glacier retreat boundaries courtesy of the U.S. Land Processes Distributed Active Archive Center...

128

Malaspina Glacier, Alaska  

NASA Technical Reports Server (NTRS)

This image from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra satellite covers an area of 55 by 40 kilometers (34 by 25 miles) over the southwest part of the Malaspina Glacier and Icy Bay in Alaska. The composite of infrared and visible bands results in the snow and ice appearing light blue, dense vegetation is yellow-orange and green, and less vegetated, gravelly areas are in orange. According to Dr. Dennis Trabant (U.S. Geological Survey, Fairbanks, Alaska), the Malaspina Glacier is thinning. Its terminal moraine protects it from contact with the open ocean; without the moraine, or if sea level rises sufficiently to reconnect the glacier with the ocean, the glacier would start calving and retreat significantly. ASTER data are being used to help monitor the size and movement of some 15,000 tidal and piedmont glaciers in Alaska. Evidence derived from ASTER and many other satellite and ground-based measurements suggests that only a few dozen Alaskan glaciers are advancing. The overwhelming majority of them are retreating.

This ASTER image was acquired on June 8, 2001. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next six years to map and monitor the changing surface of our planet.

ASTER is one of five Earth-observing instruments launched December 18,1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. science team leader; Bjorn Eng of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The Terra mission is part of NASA's Earth Science Enterprise, along-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as a total integrated system.

The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

Size: 55 by 40 kilometers (34 by 25 miles) Location: 60.0 degrees North latitude, 140.7 degrees West longitude Orientation: North at top Image Data: ASTER bands 2, 3 and 4 Original Data Resolution: 15 meters (49 feet) Date Acquired: June 8, 2001

2001-01-01

129

Physical and chemical properties of ice in a main valley glacier and a tributary glacier, Gornergletscher,  

E-print Network

Physical and chemical properties of ice in a main valley glacier and a tributary glacier properties of ice in a main valley glacier and a tributary glacier, Gornergletscher, Canton Valais, Switzerland Annika M. Quick Department of Geological Sciences Master of Science Glacier models often fail

Seamons, Kent E.

130

Patagonia Glacier, Chile  

NASA Technical Reports Server (NTRS)

This ASTER images was acquired on May 2, 2000 over the North Patagonia Ice Sheet, Chile near latitude 47 degrees south, longitude 73 degrees west. The image covers 36 x 30 km. The false color composite displays vegetation in red. The image dramatically shows a single large glacier, covered with crevasses. A semi-circular terminal moraine indicates that the glacier was once more extensive than at present. ASTER data are being acquired over hundreds of glaciers worldwide to measure their changes over time. Since glaciers are sensitive indicators of warming or cooling, this program can provide global data set critical to understand climate change.

This image is located at 46.5 degrees south latitude and 73.9 degrees west longitude.

Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud morphology and physical properties, wetlands Evaluation, thermal pollution monitoring, coral reef degradation, surface temperature mapping of soils and geology, and measuring surface heat balance.

2000-01-01

131

Widespread evidences of hoarfrost formation at a rock glacier in the Seckauer Tauern, Austria  

NASA Astrophysics Data System (ADS)

The mechanism of deep reversible air circulation (the so called "chimney effect" or "wind tube") is known to be a process of ground overcooling in the lower and deeper parts of porous sediments and related landforms such as scree slopes or intact and relict rock glaciers. Warm air outflow emerging from relatively small voids within these mostly coarse-grained sediment bodies is sometimes noticeable. However, easier to identify are associated phenomena such as snowmelt windows, snow cover depressions and hoarfrost formations. Generally, these indications for warm air outflow are found at the upper part of scree slopes or the rooting zone of rock glaciers. Here we present widespread field evidences of hoarfrost from the pseudo-relict Schneben Rock Glacier in the Seckauer Tauern Range, Austria located at E1440'26'' and N4722'31''. Herewith, a pseudo-relict rock glacier is defined as an intermediate rock glacier type between a relict and a climatic-inactive rock glacier, hence a relict rock glacier with locally isolated patches of permafrost. The rock glacier covers an area of about 0.11km2, ranges from ca. 1720 to 1905 m a.s.l., and consists predominantly of coarse-grained gneissic sediments with blocks up to a size of several cubic metres at the surface. In particular the lower part and some ridges in the central and upper part are covered by dwarf pines (pinus mugo) mirroring the flow structure of the previously active rock glacier. Isolated permafrost occurs presumably at the rooting zone of the rock glacier as indicated by evidences from a neighbouring rock glacier in a comparable setting. Field observations in November 2011 showed widespread occurrences of hoarfrost crystals growing around the funnel edge indicating the sublimation of vapour from warm funnels. Such hoarfrost sites were found at more than 50 single locations distributed over the entire rock glacier from the tongue to the rooting zone generally. The occurrence of hoarfrost can get classified into the following classes: (a) at foot slope positions, (b) along linear structures or depressions of the rock glacier, (c) below vegetation patches of dwarf pines, (d) at the interface between younger fine-grained sediments (derived from debris flows) and the coarse-grained former rock glacier surface, and finally (e) hoarfrost occurrence at the rock glacier body without any identifiable structure in the vicinity. Examples from these different hoarfrost classes are presented and discussed.

Kellerer-Pirklbauer, A.; Winkler, G.; Pauritsch, M.

2012-04-01

132

Primer on glacier flows Christian Heining  

E-print Network

Primer on glacier flows Christian Heining University of Bayreuth, Germany, Department of Applied Mechanics and Fluid Dynamics 1. Why is it important to understand the physics of glaciers? - Glaciers ocean sediments (ice shelfs in antarctica) o pollen - Glaciers contribute to the raise

Sainudiin, Raazesh

133

Glacier Shrinkage and Effects on Alpine Hydrology  

Microsoft Academic Search

Alpine glaciers cover an area of about 553 km2 in seven western states of the American West. With few exceptions, all glaciers have been shrinking over the past century and the rate of shrinkage has accelerated over the past few decades. Overall, smaller glaciers exhibit greatest shrinkage, relative to their size, compared to larger glaciers. Preliminary results from studies of

H. Basagic; A. G. Fountain; D. H. Clark

2004-01-01

134

Canadian Glacier Hydrology, 2003-2007  

Microsoft Academic Search

Glacier hydrological research in Canada from 2002-2007 continues to advance, driven by new observations of glacier retreat in all regions of the country. New observation networks have been formed to study various aspects of glacier change and linkages with the hydrological system. Small- scale studies of accumulation and melt processes on glacier surfaces continue, and are being used to parameterize

Sarah Boon; Gwenn E. Flowers; D. Scott Munro

2009-01-01

135

Recent behaviour of Slovenian glaciers  

NASA Astrophysics Data System (ADS)

Just two glaciers, below the peaks of Triglav (2864 m) and Skuta (2532 m), are persisting in Slovenian Alps, both on a relatively very low elevation. Their present surfaces do not exceed one hectare, thus we can speak only about two glacierets or very small glaciers. The Anton Melik Geographical Institute of the Scientific Research Centre at the Slovenian Academy of Sciences and Arts has regularly performed measurements since 1946. The size of the Triglav glacier, measured in 1946, was 14.4 hectares, and by the year 2012 the glacier had shrunk to a half of a hectare. The direct vicinity of the meteorological station on Mt. Kredarica makes possible an analysis of the dependency of the glacier's fluctuation on weather changes. Several methods of measuring have been applied. Since 1999 we have regularly performed photogrammetric measurements of the glacier, which render possible exact calculations of changes in the glacier's area and volume by individual years. In addition, we also performed georadar measurements in 2000 and 2013. Besides regular annual measurements performed at the end of melting seasons, the Triglav glacier has also been photographed monthly since 1976, from two fixed positions on Mt. Kredarica. In 2012, we performed aerial laser scanning (LIDAR) of the Triglav glacier. While for the last decade of the 20th century we reported that the Triglav glacier has not only retreated but literally disintegrated, in the first decade of the 21st century we can observe its stagnation. Due to the present concave form of the glacier's surface, snow remains on it late into summer, and since the year 2007, the ice of the lower part of the glacier has not been revealed even at the end of the melting season but has remained covered with the firn and snow of previous winters. Should such weather conditions continue and the amount of winter precipitation further increase, the remainder of the Triglav glacier will, though very small in size, continue to exist for next ten years or even more.

Gabrovec, Matej; Ferk, Mateja; Ortar, Jaka

2014-05-01

136

Seasonal changes in surface albedo of Himalayan glaciers from MODIS data and links with the annual mass balance  

NASA Astrophysics Data System (ADS)

Few glaciological field data are available on glaciers in the Hindu Kush - Karakoram - Himalaya (HKH) region, and remote sensing data are thus critical for glacier studies in this region. The main objectives of this study are to document, using satellite images, the seasonal changes of surface albedo for two Himalayan glaciers, Chhota Shigri Glacier (Himachal Pradesh, India) and Mera Glacier (Everest region, Nepal), and to reconstruct the annual mass balance of these glaciers based on the albedo data. Albedo is retrieved from MODerate Imaging Spectroradiometer (MODIS) images, and evaluated using ground based measurements. At both sites, we find high coefficients of determination between annual minimum albedo averaged over the glacier (AMAAG) and glacier-wide annual mass balance (Ba) measured with the glaciological method (R2 = 0.75). At Chhota Shigri Glacier, the relation between AMAAG found at the end of the ablation season and Ba suggests that AMAAG can be used as a proxy for the maximum snowline altitude or equilibrium line altitude (ELA) on winter accumulation-type glaciers in the Himalayas. However, for the summer-accumulation type Mera Glacier our approach relied on the hypothesis that ELA information, mostly not accessible from space during the monsoon, was still preserved later thanks to strong winter winds blowing away snow and in turn exposing again the late monsoon surface. AMAAG was subsequently revealed in the post-monsoon period. Reconstructed Ba at Chhota Shigri Glacier agrees with mass balances previously reconstructed using a positive degree-day method. Reconstructed Ba at Mera Glacier is affected by heavy cloud cover during the monsoon, which systematically limited our ability to observe AMAAG at the end of the melting period. In addition, the relation between AMAAG and Ba is constrained over a shorter time period for Mera Glacier (6 years) than for Chhota Shigri Glacier (11 years). Thus the mass balance reconstruction is less robust for Mera Glacier than for Chhota Shigri Glacier. However our method shows promising results and may be used to reconstruct the annual mass balance of glaciers with contrasted seasonal cycles in the western part of the HKH mountain range since the early 2000s when MODIS images became available.

Brun, F.; Dumont, M.; Wagnon, P.; Berthier, E.; Azam, M. F.; Shea, J. M.; Sirguey, P.; Rabatel, A.; Ramanathan, Al.

2014-06-01

137

Teleconnections between Andean and New Zealand glaciers  

Microsoft Academic Search

Retreat and advance of glaciers in the Southern Alps of New Zealand have occurred over two distinct 20-yr climate periods (19541974) and (19741994). Changes in tropical and southern Andean glaciers are compared over these same periods. Behaviour of glaciers in the tropical Andes are out of phase with the Southern Alps glaciers, but some glaciers in Patagonia appear to be

B. Blair Fitzharris; Gareth R. Clare; Jim Renwick

2007-01-01

138

Younger Dryas and early Holocene age glacier advances in Patagonia  

NASA Astrophysics Data System (ADS)

Reliable dating of Southern Hemisphere glacier fluctuations since the Last Glacial Maximum (LGM) is crucial to resolving debates about millennial-scale climate change. Here we present 10Be dates for lateral, valley-mouth and cross-valley moraines formed between the contemporary South American North Patagonian Icefield (NPI) and its LGM position in four separate valleys around 47S. This is an area near the core of the precipitation-bearing southern westerly winds, where it is known that rapid shifts in climate occurred during Lateglacial times. The dates indicate that outlet glaciers advanced, or at least stabilised, to form large moraines east of an expanded NPI at 11.0 0.5/11.2 0.6, 11.5 0.6, 11.7 0.6 and 12.8 0.7 ka (Putnam southern-hemisphere production rates and Dunai scaling scheme, assumed boulder erosion rate of 2 mm/ka). Four of these ages are statistically indistinguishable and probably represent a single, regional ice advance. The dates indicate that glaciers in Patagonia were larger during these times than at any point since the LGM and provide evidence in Patagonia for glacier advances around the time of the European Younger Dryas (12.9-11.7 ka) and into the very early Holocene. Although palaeoclimatic records from this area are often contradictory, these glacier advances were probably associated with a period of cooling or regionally increased precipitation related to the changes in the position of the southern westerly winds.

Glasser, Neil F.; Harrison, Stephan; Schnabel, Christoph; Fabel, Derek; Jansson, Krister N.

2012-12-01

139

Methods of Measuring Glacier Change  

NASA Astrophysics Data System (ADS)

In the 19th century measuring glacier change was limited to measuring the position of the glacier front, or terminus. By the mid 20th century, change measurements expanded to include aerial photogrammetry and field-based mass balance methods. The latter were typically based on stakes drilled into a glacier, against which snow accumulation and ice loss were measured. Knowing the density of the surface material and area of the glacier, the mass change can be calculated. This approach still provides the most detailed information on glacier mass change. At the turn of the new millennium, the increased sophistication of aerial and satellite remote sensing technology and computer software have provided numerous new approaches to assessing glacier change. In particular, airborne laser altimetry can be used to define the altitude of a glacier surface and over time provides changes in glacier volume. Traditional aerial photogrammetry has been revitalized by tracking feature displacement to provide a displacement field over the glacier surface and inferring point estimates of mass change based on a numerical model of continuity. The same technique can be used with a scanning laser altimeter. Satellite images can be used to track glacier change both in the form of aerial changes and by feature tracking. However due to current image resolutions the satellite imagery has been restricted to large ice fields on ice sheets. This may change in the near future. Synthetic aperture radar (SAR) satellites provide an enormous potential for tracking glaciers because interferometric techniques can also be used to infer a displacement field, and surface features can be investigated such as the snow line, and the transition between wet and dry snow. The all weather capabilities of SAR including day/night imaging, make it a particularly attractive sensor. One has to be clear, however, that these various techniques provide somewhat different information about glacier change and some caution must be taken when comparing the results of these methods. Databases of glacier change has largely been the responsibility of the World Glacier Monitoring Service (WGMS). That database is based on scalar quantities of glacier geometries and change, such as, mass change, length change, mean elevation, and so on. When first established it was the only practical type of database. With the rapid development of increasing computer memory and speed, and analytic software, particularly geographic information systems (GIS), we are no longer restricted to scalar databases. Within a GIS we can store, in digital form, historic maps of glacier surfaces, aerial photography including digital orthophotoquadrangles, satellite imagery and products derived from laser altimetry. In addition, we can store interpretative products and metadata including references to relevant scientific reports. Thus an investigator will have the original data and derived products at their disposal. The availability of original data is particularly important in view of expected future advances in computational methods. A GIS database will contribute to the WGMS efforts and accelerate our ability to exchange data internationally and increase our understanding of the spatial and temporal components of glacier change. Current efforts in this direction need to be encouraged and expanded.

Fountain, A. G.

2001-12-01

140

Pine Island Glacier, Antarctica  

NASA Technical Reports Server (NTRS)

This ASTER image was acquired on December 12, 2000, and covers an area of 38 x 48 km. Pine Island Glacier has undergone a steady loss of elevation with retreat of the grounding line in recent decades. Now, space imagery has revealed a wide new crack that some scientists think will soon result in a calving event. Glaciologist Robert Bindschadler of NASA's Goddard Space Flight Center predicts this crack will result in the calving of a major iceberg, probably in less than 18 months. Discovery of the crack was possible due to multi-year image archives and high resolution imagery. This image is located at 74.1 degrees south latitude and 105.1 degrees west longitude.

The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

2001-01-01

141

Gallery Walk Questions about Glaciers  

NSDL National Science Digital Library

created by Mark Francek, Central Michigan University The following are potential questions that could be used in a gallery walk activity about glaciers. The questions are organized according to the cognitive level ...

142

Flow instabilities of Alaskan glaciers  

NASA Astrophysics Data System (ADS)

Over 300 of the largest glaciers in southern Alaska have been identified as either surge-type or pulse-type, making glaciers with flow instabilities the norm among large glaciers in that region. Consequently, the bulk of mass loss due to climate change will come from these unstable glaciers in the future, yet their response to future climate warming is unknown because their dynamics are still poorly understood. To help broaden our understanding of unstable glacier flow, the decadal-scale ice dynamics of 1 surging and 9 pulsing glaciers are investigated. Bering Glacier had a kinematic wave moving down its ablation zone at 4.4 +/- 2.0 km/yr from 2002 to 2009, which then accelerated to 13.9 +/- 2.0 km/yr as it traversed the piedmont lobe. The wave first appeared in 2001 near the confluence with Bagley Ice Valley and it took 10 years to travel ~64 km. A surge was triggered in 2008 after the wave activated an ice reservoir in the midablation zone, and it climaxed in 2011 while the terminus advanced several km into Vitus Lake. Ruth Glacier pulsed five times between 1973 and 2012, with peak velocities in 1981, 1989, 1997, 2003, and 2010; approximately every 7 years. A typical pulse increased ice velocity 300%, from roughly 40 m/yr to 160 m/yr in the midablation zone, and involved acceleration and deceleration of the ice en masse; no kinematic wave was evident. The pulses are theorized to be due to deformation of a subglacial till causing enhanced basal motion. Eight additional pulsing glaciers are identified based on the spatiotemporal pattern of their velocity fields. These glaciers pulsed where they were either constricted laterally or joined by a tributary, and their surface slopes are 1-2. These traits are consistent with an overdeepening. This observation leads to a theory of ice motion in overdeepenings that explains the cyclical behavior of pulsing glaciers. It is based on the concept of glaciohydraulic supercooling, and includes sediment transport and erosion along an adverse slope, ice thickening, and ablation of the ice surface such that the ratio of the angle of the adverse slope to ice surface slope oscillates around the supercooling threshold.

Turrin, James Bradley

143

Instructions for Glacier Recession Lesson Objective: Students will learn  

E-print Network

Instructions for Glacier Recession Lesson Objective: Students will learn: - about the connection between glaciers and climate, - why glacial studies are important, - how glacier recession affects humanity, and - how humans are affecting glaciers. Materials: Movie ­ Inconvenient Truth For Exercise

144

Water, ice, and meteorological measurements at South Cascade Glacier, Washington, 2000-01 balance years  

USGS Publications Warehouse

Winter snow accumulation and summer snow, firn, and ice melt were measured at South Cascade Glacier, Washington, to determine the winter and net balances for the 2000 and 2001 balance years. In 2000, the winter balance, averaged over the glacier, was 3.32 meters, and the net balance was 0.38 meters. The winter balance was the ninth highest since the record began in 1959. The net balance was greater than 33 of the 41 years since 1959. In 2001, the winter balance was 1.90 meters, and net balance was -1.57 meters. The winter balance was lower than all but 4 years since 1959, and the net balance was more negative than all but 5 other years. Runoff was measured from the glacier basin and an adjacent non-glacierized basin. Air temperature, precipitation, humidity, wind speed and solar radiation were measured nearby. Ice displacements were measured for the 1998-2001 period.

Krimmel, Robert M.

2002-01-01

145

Glacial ice and atmospheric forcing on the Mertz Glacier Polynya over the past 250 years.  

PubMed

The Mertz Glacier Polynya off George V Land, East Antarctica, is a source of Adlie Land Bottom Water, which contributes up to ~25% of the Antarctic Bottom Water. This major polynya is closely linked to the presence of the Mertz Glacier Tongue that traps pack ice upstream. In 2010, the Mertz Glacier calved a massive iceberg, deeply impacting local sea ice conditions and dense shelf water formation. Here we provide the first detailed 250-year long reconstruction of local sea ice and bottom water conditions. Spectral analysis of the data sets reveals large and abrupt changes in sea surface and bottom water conditions with a ~70-year cyclicity, associated with the Mertz Glacier Tongue calving and regrowth dynamics. Geological data and atmospheric reanalysis, however, suggest that sea ice conditions in the polynya were also very sensitive to changes in surface winds in relation to the recent intensification of the Southern Annular Mode. PMID:25803779

Campagne, P; Crosta, Xavier; Houssais, M N; Swingedouw, D; Schmidt, S; Martin, A; Devred, E; Capo, S; Marieu, V; Closset, I; Mass, G

2015-01-01

146

Ancient carbon from a melting glacier gives high 14C age in living pioneer invertebrates  

PubMed Central

Glaciers are retreating and predatory invertebrates rapidly colonize deglaciated, barren ground. The paradox of establishing predators before plants and herbivores has been explained by wind-driven input of invertebrate prey. Here we present an alternative explanation and a novel glacier foreland food web by showing that pioneer predators eat locally produced midges containing 21,000 years old ancient carbon released by the melting glacier. Ancient carbon was assimilated by aquatic midge larvae, and terrestrial adults achieved a radiocarbon age of 1040 years. Terrestrial spiders, harvestmen and beetles feeding on adult midges had radiocarbon ages of 3401100 years. Water beetles assumed to eat midge larvae reached radiocarbon ages of 11001200 years. Because both aquatic and terrestrial pioneer communities use ancient carbon, the term primary succession is questionable in glacier forelands. If our old invertebrates had been collected as subfossils and radiocarbon dated, their age would have been overestimated by up to 1100 years. PMID:24084623

Hgvar, Sigmund; Ohlson, Mikael

2013-01-01

147

Ancient carbon from a melting glacier gives high ?C age in living pioneer invertebrates.  

PubMed

Glaciers are retreating and predatory invertebrates rapidly colonize deglaciated, barren ground. The paradox of establishing predators before plants and herbivores has been explained by wind-driven input of invertebrate prey. Here we present an alternative explanation and a novel glacier foreland food web by showing that pioneer predators eat locally produced midges containing 21,000 years old ancient carbon released by the melting glacier. Ancient carbon was assimilated by aquatic midge larvae, and terrestrial adults achieved a radiocarbon age of 1040 years. Terrestrial spiders, harvestmen and beetles feeding on adult midges had radiocarbon ages of 340-1100 years. Water beetles assumed to eat midge larvae reached radiocarbon ages of 1100-1200 years. Because both aquatic and terrestrial pioneer communities use ancient carbon, the term "primary succession" is questionable in glacier forelands. If our "old" invertebrates had been collected as subfossils and radiocarbon dated, their age would have been overestimated by up to 1100 years. PMID:24084623

Hgvar, Sigmund; Ohlson, Mikael

2013-01-01

148

Seasonal and annual mass balances of Mera and Pokalde glaciers (Nepal Himalaya) since 2007  

NASA Astrophysics Data System (ADS)

In the Everest region, Nepal, ground-based monitoring programmes were started on the debris-free Mera Glacier (27.7 N, 86.9 E; 5.1 km2, 6420 to 4940 m a.s.l.) in 2007 and on the small Pokalde Glacier (27.9 N, 86.8 E; 0.1 km2, 5690 to 5430 m a.s.l., ~ 25 km north of Mera Glacier) in 2009. These glaciers lie on the southern flank of the central Himalaya under the direct influence of the Indian monsoon and receive more than 80% of their annual precipitation in summer (June to September). Despite a large inter-annual variability with glacier-wide mass balances ranging from -0.67 0.28 m w.e. in 2011-2012 (Equilibrium-line altitude (ELA) at ~ 5800 m a.s.l.) to +0.46 0.28 m w.e. in 2010-2011 (ELA at ~ 5340 m a.s.l.), Mera Glacier has been shrinking at a moderate mass balance rate of -0.08 0.28 m w.e. yr-1 since 2007. Ice fluxes measured at two distinct transverse cross sections at ~ 5350 m a.s.l. and ~ 5520 m a.s.l. confirm that the mean state of this glacier over the last one or two decades corresponds to a limited mass loss, in agreement with remotely-sensed region-wide mass balances of the Everest area. Seasonal mass balance measurements show that ablation and accumulation are concomitant in summer which in turn is the key season controlling the annual glacier-wide mass balance. Unexpectedly, ablation occurs at all elevations in winter due to wind erosion and sublimation, with remobilised snow potentially being sublimated in the atmosphere. Between 2009 and 2012, the small Pokalde Glacier lost mass more rapidly than Mera Glacier with respective mean glacier-wide mass balances of -0.72 and -0.23 0.28 m w.e. yr-1. Low-elevation glaciers, such as Pokalde Glacier, have been usually preferred for in-situ observations in Nepal and more generally in the Himalayas, which may explain why compilations of ground-based mass balances are biased toward negative values compared with the regional mean under the present-day climate.

Wagnon, P.; Vincent, C.; Arnaud, Y.; Berthier, E.; Vuillermoz, E.; Gruber, S.; Mngoz, M.; Gilbert, A.; Dumont, M.; Shea, J. M.; Stumm, D.; Pokhrel, B. K.

2013-11-01

149

Seasonal and annual mass balances of Mera and Pokalde glaciers (Nepal Himalaya) since 2007  

NASA Astrophysics Data System (ADS)

In the Everest region, Nepal, ground-based monitoring programs were started on the debris-free Mera Glacier (27.7 N, 86.9 E; 5.1 km2, 6420 to 4940 m a.s.l.) in 2007 and on the small Pokalde Glacier (27.9 N, 86.8 E; 0.1 km2, 5690 to 5430 m a.s.l., 25 km North of Mera Glacier) in 2009. These glaciers lie on the southern flank of the central Himalaya under the direct influence of the Indian monsoon and receive more than 80% of their annual precipitation in summer (June to September). Despite a large inter-annual variability with glacier-wide mass balances ranging from -0.77 0.40 m w.e. in 2011-2012 (Equilibrium-line altitude (ELA) at 6055 m a.s.l.) to + 0.46 0.40 m w.e. in 2010-2011 (ELA at 5340 m a.s.l.), Mera Glacier has been shrinking at a moderate mass balance rate of -0.10 0.40 m w.e. yr-1 since 2007. Ice fluxes measured at two distinct transverse cross sections at 5350 m a.s.l. and 5520 m a.s.l. confirm that the mean state of this glacier over the last one or two decades corresponds to a limited mass loss, in agreement with remotely-sensed region-wide mass balances of the Everest area. Seasonal mass balance measurements show that ablation and accumulation are concomitant in summer which in turn is the key season controlling the annual glacier-wide mass balance. Unexpectedly, ablation occurs at all elevations in winter due to wind erosion and sublimation, with remobilized snow likely being sublimated in the atmosphere. Between 2009 and 2012, the small Pokalde Glacier lost mass more rapidly than Mera Glacier with respective mean glacier-wide mass balances of -0.72 and -0.26 0.40 m w.e. yr-1. Low-elevation glaciers, such as Pokalde Glacier, have been usually preferred for in-situ observations in Nepal and more generally in the Himalayas, which may explain why compilations of ground-based mass balances are biased toward negative values compared with the regional mean under the present-day climate.

Wagnon, P.; Vincent, C.; Arnaud, Y.; Berthier, E.; Vuillermoz, E.; Gruber, S.; Mngoz, M.; Gilbert, A.; Dumont, M.; Shea, J. M.; Stumm, D.; Pokhrel, B. K.

2013-07-01

150

Modelling Greenland Outlet Glaciers  

NASA Technical Reports Server (NTRS)

The objective of this project was to develop simple yet realistic models of Greenland outlet glaciers to better understand ongoing changes and to identify possible causes for these changes. Several approaches can be taken to evaluate the interaction between climate forcing and ice dynamics, and the consequent ice-sheet response, which may involve changes in flow style. To evaluate the icesheet response to mass-balance forcing, Van der Veen (Journal of Geophysical Research, in press) makes the assumption that this response can be considered a perturbation on the reference state and may be evaluated separately from how this reference state evolves over time. Mass-balance forcing has an immediate effect on the ice sheet. Initially, the rate of thickness change as compared to the reference state equals the perturbation in snowfall or ablation. If the forcing persists, the ice sheet responds dynamically, adjusting the rate at which ice is evacuated from the interior to the margins, to achieve a new equilibrium. For large ice sheets, this dynamic adjustment may last for thousands of years, with the magnitude of change decreasing steadily over time as a new equilibrium is approached. This response can be described using kinematic wave theory. This theory, modified to pertain to Greenland drainage basins, was used to evaluate possible ice-sheet responses to perturbations in surface mass balance. The reference state is defined based on measurements along the central flowline of Petermann Glacier in north-west Greenland, and perturbations on this state considered. The advantage of this approach is that the particulars of the dynamical flow regime need not be explicitly known but are incorporated through the parameterization of the reference ice flux or longitudinal velocity profile. The results of the kinematic wave model indicate that significant rates of thickness change can occur immediately after the prescribed change in surface mass balance but adjustments in flow rapidly diminish these rates to a few cm/yr at most. The time scale for adjustment is of the order of a thousand years or so.

vanderVeen, Cornelis; Abdalati, Waleed (Technical Monitor)

2001-01-01

151

Aletsch Glacier, Switzerland  

NASA Technical Reports Server (NTRS)

Aletsch Glacier, the largest glacier of Europe, covers more than 120 square kilometers (more than 45 square miles)in southern Switzerland. At its eastern extremity lies a glacierlake, Mdrjelensee (2,350 meters/7,711 feet above sea level). To the west rises Aletschhorn (4,195 meters/13,763 feet), which was first climbed in 1859. The Rhone River flows along the southern flank of the mountains.

This image was acquired on July 23, 2001 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. The Terra mission is part of NASA's Earth Science Enterprise, a long-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as a total integrated system.

Size: 60 x 56 km (37.2 x 34.7 miles) Location: 46.5 deg. North lat., 8.0 deg. East long. Orientation: North at top Image Data: ASTER bands 1,2, and 3. Original Data Resolution: 15 m Date Acquired: July 23, 2001

2002-01-01

152

Quantifying Spatially-Variable Ablation of Bering Glacier Lobes Using Low-Cost Automated Samplers and Remote Sensing Imagery  

NASA Astrophysics Data System (ADS)

The Bering Glacier is the largest and longest glacier in continental North America, with an area of approximately 5,175 km2 and a length of 190 km. It is also the largest surging glacier in America, having surged at least five times during the twentieth century. Bering Glacier alone covers more than 6% of the glacier covered area of Alaska and may contain 15-20% of Alaska's total glacier ice. The entire glacier lies within 100 km of the Gulf of Alaska. The last great surge of the Bering Glacier occurred in 1993-95. An interdisciplinary research team has been actively monitoring the Bering Glacier since 2000, in order to understand the post-surge dynamics in respect to its effect on the Bering Glacier system hydrology. A comprehensive sampling of the lakes, rivers, runoff, and glacier volumetric change is being conducted to understand how changes in the glacier affect the hydrological environment which in turn determines the individual habitat of the flora and fauna that defines the ecology of the region. The monitoring program consists of a combination of highly-detailed local measurements with coarser resolution measurements over large spatial extents. Detailed measurements were collected using an inexpensive, field-deployable data measurement and logging system was designed and fabricated in 2004. The Glacier Ablation Sensor System (GASS) collects environmental information on glacier melting (temperature, barometric pressure, light level, wind speed) and movement (GPS coordinates, depth to glacier surface). The system uses solar cells with a battery to provide the required power, and is capable of storing an entire summer season's worth of hourly data. A set of GASS units (5-8) were deployed during the summers of 2004, 2005, and 2006 on the Bering and Stellar lobes of the Bering Glacier. To complement the local measurements, optical remote sensing imagery has been collected to monitor changes in the glacial terminus and to quantify the spatial variability of albedo. Spatially-variable estimates of ablation were made using an empirical model for the extent of the glacial lobes. The empirical model terms are based on a full energy balance model, and include sensible, latent, and radiative heat fluxes. Point measurements of environmental parameters were spatially distributed based on empirical relationships between parameters and elevation. Temporally- and spatially-variable albedo was estimated based on optical remote sensing data. Discharge to the terminal lakes was estimated based on the modeled ablation, and compared to limited discharge measurements.

Shuchman, R.; Josberger, E.; Erickson, T. A.; Hatt, C.; Liversedge, L.; Roussi, C.; Payne, J. F.

2006-12-01

153

Climatic controls of western U.S. glaciers at the last glacial maximum  

USGS Publications Warehouse

We use a nested atmospheric modeling strategy to simulate precipitation and temperature of the western United States 18,000 years ago (18 ka). The high resolution of the nested model allows us to isolate the regional structure of summer temperature and winter precipitation that is crucial to determination of the net mass balance of late-Pleistocene mountain glaciers in this region of diverse topography and climate. Modeling results suggest that climatic controls of these glaciers varied significantly over the western U.S. Glaciers in the northern Rocky Mountains existed under relatively cold July temperatures and low winter accumulation, reflecting anticyclonic, easterly wind flow off the Laurentide Ice Sheet. In contrast, glaciers that existed under relatively warmer and wetter conditions are located along the Pacific coast south of Oregon, where enhanced westerlies delivered higher precipitation than at present. Between these two groupings lie glaciers that were controlled by a mix of cold and wet conditions attributed to the convergence of cold air from the ice sheet and moisture derived from the westerlies. Sensitivity tests suggest that, for our simulated 18 ka climate, many of the glaciers exhibit a variable response to climate but were generally more sensitive to changes in temperature than to changes in precipitation, particularly those glaciers in central Idaho and the Yellowstone Plateau. Our results support arguments that temperature depression generally played a larger role in lowering equilibrium line altitudes in the western U.S. during the last glacial maximum than did increased precipitation, although the magnitude of temperature depression required for steady-state mass balance varied from 8-18??C. Only the Sierra Nevada glaciers required a substantial increase in precipitation to achieve steady-state mass balance, while glaciers in the Cascade Range existed with decreased precipitation.

Hostetler, S.W.; Clark, P.U.

1997-01-01

154

Response of glaciers in northwestern North America to future climate change: an atmosphere/glacier  

E-print Network

Response of glaciers in northwestern North America to future climate change: an atmosphere/glacier@gi.alaska.edu 2 HyMet, Inc., 13629 Burma Road SW, Vashon Island, WA 98070, USA ABSTRACT. The response of glaciers to changing climate is explored with an atmosphere/glacier hierarchical modeling approach, in which global

Bhatt, Uma

155

Annual satellite imaging of the world's glaciers Assessment of glacier extent and change  

E-print Network

GLIMS HIGH ICE Annual satellite imaging of the world's glaciers Assessment of glacier extent and change Development and population of a digital glacier data inventory #12;Skeletal remains of what was a debris-covered glacier near Mt. Everest J.S. Kargel, April 2001 #12;#12;#12;Global Land Ice Measurements

156

The GLIMS geospatial glacier database: A new tool for studying glacier change  

E-print Network

The GLIMS geospatial glacier database: A new tool for studying glacier change Bruce Raup a,, Adina's estimated 160000 glaciers. Each institution (called a Regional Center, or RC) oversees the analysis of satellite imagery for a particular region containing glacier ice. Data received by the GLIMS team

157

Rapid Thinning of a Lake Calving Glacier: Yakutat Glacier, Southeast Alaska  

Microsoft Academic Search

Calving glaciers around the world have recently undergone a rapid retreat and are important contributors to global sea level rise. Due to their greatly increased mass loss, tidewater glaciers in particular have long received much attention, whereas lake calving glaciers have just been identified as significant contributors. In southeast Alaska, numerous glaciers have experienced rapid retreat and significant thinning during

B. Truessel; R. J. Motyka; C. F. Larsen; M. Truffer

2010-01-01

158

Dating of Little Ice Age glacier fluctuations in the tropical Andes: Charquini glaciers, Bolivia, 16S  

Microsoft Academic Search

Fluctuations of the Charquini glaciers (Cordillera Real, Bolivia) have been reconstructed for the Little Ice Age (LIA) from a set of 10 moraines extending below the present glacier termini. A lichenometric method using the Rhizocarpon geographicum was used to date the moraines and reconstruct the main glacier fluctuations over the period. The maximum glacier extent occurred in the second half

Antoine Rabatel; Vincent Jomelli; Philippe Naveau; Bernard Francou; Delphine Grancher

2005-01-01

159

The triggering of subglacial lake drainage during rapid glacier drawdown: Crane Glacier, Antarctic Peninsula  

E-print Network

The triggering of subglacial lake drainage during rapid glacier drawdown: Crane Glacier, Antarctic Glacier, Antarctic Peninsula, shows an unusual temporal pattern of elevation loss: a period of very rapid is not seen. Bathymetry in Crane Glacier fjord reveals a series of flat-lying, formerly subglacial deeps

Paris-Sud XI, Université de

160

Assessment of multispectral glacier mapping methods and derivation of glacier area changes, 19782002, in the central  

E-print Network

Assessment of multispectral glacier mapping methods and derivation of glacier area changes, 1978 56, Dunedin 9054, New Zealand ABSTRACT. We have measured the glacier area changes in the central Southern Alps, New Zealand, between 1978 and 2002 and have compiled the 2002 glacier outlines using

Kääb, Andreas

161

High Altitude Glaciers in the Tropics  

NSDL National Science Digital Library

While it may seem like a contradiction, glaciers do exist in the tropical latitudes. In this video produced by ThinkTV, learn about tropical glaciers and why scientists are studying them to better understand global climate change.

ThinkTV

2010-11-30

162

Survey of glaciers in the northern Rocky Mountains of Montana and Wyoming; Size response to climatic fluctuations 1950-1996  

SciTech Connect

An aerial survey of Northern Rocky Mountain glaciers in Montana and Wyoming was conducted in late summer of 1996. The Flathead, Swan, Mission, and Beartooth Mountains of Montana were covered, as well as the Teton and Wind River Ranges of Wyoming. Present extent of glaciers in this study were compared to limits on recent USGS 15 and 7.5 topographic maps, and also from selected personal photos. Large cirque and hanging glaciers of the Flathead and Wind River Ranges did not display significant decrease in size or change in terminus position. Cirque glaciers in the Swan, Mission, Beartooth and Teton Ranges were markedly smaller in size; with separation of the ice body, growth of the terminus lake, or cover of the ice terminus with rockfalls. A study of annual snowfall, snowdepths, precipitation, and mean temperatures for selected stations in the Northern Rocky Mountains indicates no extreme variations in temperature or precipitation between 1950-1996, but several years of low snowfall and warmer temperatures in the 1980`s appear to have been sufficient to diminish many of the smaller cirque glaciers, many to the point of extinction. The disappearance of small cirque glaciers may indicate a greater sensitivity to overall climatic warming than the more dramatic fluctuations of larger glaciers in the same region.

Chatelain, E.E. [Valdosta State Univ., GA (United States)

1997-09-01

163

Glacier Mass Balance measurements in Bhutan  

NASA Astrophysics Data System (ADS)

Long-term glacier measurements are scarce in the Himalayas, partly due to lack of resources as well as inaccessibility of most of the glaciers. There are over 600 glaciers in Bhutan in the Eastern Himalayas, but no long-term measurements. However, such studies are an important component of hydrological modelling, and especially relevant to the proposed expansion of hydropower resources in this area. Glaciological studies are also critical to understanding the risk of jkulhlaups or GLOFS (glacier lake outburst floods) from glaciers in this region. Glacier mass balance measurements have been initiated on a glacier in the Chamkhar Chu region in central Bhutan by the Department of Hydro-Met Services in co-operation with the Norwegian Water Resources and Energy Directorate. Chamkhar Chu is the site of two proposed hydropower plants that will each generate over 700 MW, although the present and future hydrological regimes in this basin, and especially the contribution from glaciers, are not well-understood at present. There are about 94 glaciers in the Chamkhar Chhu basin and total glacier area is about 75 sq. km. The glaciers are relatively accessible for the Himalayas, most of them can be reached after only 4-5 days walk from the nearest road. One of the largest, Thana glacier, has been chosen as a mass balance glacier and measurements were initiated in 2013. The glacier area is almost 5 sq. km. and the elevation range is 500 m (5071 m a.s.l. to 5725 m a.s.l.) making it suitable as a benchmark glacier. Preliminary measurements on a smaller, nearby glacier that was visited in 2012 and 2013 showed 1 m of firn loss (about 0.6 m w.eq.) over 12 months.

Jackson, Miriam; Tenzin, Sangay; Tashi, Tshering

2014-05-01

164

Where Have All the Glaciers Gone?  

NSDL National Science Digital Library

In this activity, students examine images of alpine glaciers to develop an understanding of how glaciers respond to climate change. They record, discuss, and interpret their observations. They consider explanations for changes in the size and position of glaciers from around the world. They develop an understanding that the melting (retreat) of glaciers is occurring simultaneously on different continents around the world, and, thus, they represent evidence of global climate change.

National Center For Atmospheric Research

165

The Effects of Changing Climate on Glaciers in the Central Alaska Range, Alaska, USA: A Case Study on the Kahiltna Glacier  

NASA Astrophysics Data System (ADS)

This study will develop a set of modeling tools to provide estimates of melt evolution for the Kahiltna Glacier and glaciers of the Central Alaska Range (CAKR), over a number of future climate change scenarios. To parameterize the model, field measurements of mass balance and meteorological variables are being collected on the Kahiltna Glacier. These measurements include winter accumulation surveys along both a centerline transect and several lateral profiles of the main glacier branch, and summer ablation measurements at ten centerline index locations spaced evenly over a range of elevations. Snow density measurements are also being recorded at three elevations. Temperature and relative humidity is being sampled at five of the index locations, and a full meteorological station (measuring temperature, humidity, wind speed and direction, snow accumulation, ice ablation, and solar radiation) will be positioned on the lower ablation area. Here we present preliminary results from the 2010 melt season, comparing data collected on the Kahiltna Glacier to measurements from nearby sites within the CAKR. Data from a single index site monitored by the National Park Service (NPS) is compared to the accumulation and ablation measurements taken at the ten sites visited during 2010 as part of this study, to show the NPS index sites representativeness at different elevations. Accumulation at these locations is also compared to a nearby snow telemetry (SNOTEL) site to determine whether there is a systematic offset between station data and conditions on the glacier. Lapse rates are calculated from temperature readings at five different elevations, for comparison with data from a meteorological station located in an adjacent glacier basin. From these analyses we provide a preliminary assessment of the extent to which our in situ measurements on the Kahiltna Glacier are representative of regional trends. The project will leverage 20 years of NPS mass balance data for the Kahiltna Glacier, as well as weather station data previously collected within the CAKR. Field measurements will also be supplemented with available remote sensing mass balance estimates from both the Gravity Recovery and Climate Experiment (GRACE) and aircraft laser altimetry. Results from the Kahiltna Glacier will be used to calibrate a meltwater runoff model for all glaciated areas within the CAKR. This research hopes to provide crucial information for determining current glacier conditions and the changes in meltwater runoff that can be expected over time.

Young, J. C.; Arendt, A. A.

2010-12-01

166

Analysis of time series of glacier speed: Columbia Glacier, Alaska  

USGS Publications Warehouse

During the summer of 1984 and 1985, laser measurements were made of the distance from a reference location to markers on the surface of the lower reach of Columbia Glacier, Alaska. The speed varies from 7 to 15 m/d and has three noteworthy components: 1) a low-frequency perturbation in speed with a time scale of days related to increased precipitation, 2) semidiurnal and diurnal variations related to sea tides, and 3) diurnal variations related to glacier surface melt. -from Authors

Walters, R.A.; Dunlap, W.W.

1987-01-01

167

Longitudinal surface structures (flowstripes) on Antarctic glaciers  

NASA Astrophysics Data System (ADS)

Longitudinal surface structures ("flowstripes") are common on many glaciers but their origin and significance are poorly understood. In this paper we present observations of the development of these longitudinal structures from four different Antarctic glacier systems; the Lambert Glacier/Amery Ice Shelf area, the Taylor and Ferrar Glaciers in the Ross Sea sector, Crane and Jorum Glaciers (ice-shelf tributary glaciers) on the Antarctic Peninsula, and the onset zone of a tributary to the Recovery Glacier Ice Stream in the Filchner Ice Shelf area. Mapping from optical satellite images demonstrates that longitudinal surface structures develop in two main situations: (1) as relatively wide flow stripes within glacier flow units and (2) as relatively narrow flow stripes where there is convergent flow around nunataks or at glacier confluence zones. Our observations indicate that the confluence features are narrower, sharper, and more clearly defined features. They are characterised by linear troughs or depressions on the ice surface and are much more common than the former type. Longitudinal surface structures within glacier flow units have previously been explained as the surface expression of localised bed perturbations but a universal explanation for those forming at glacier confluences is lacking. Here we propose that these features are formed at zones of ice acceleration and extensional flow at glacier confluences. We provide a schematic model for the development of longitudinal surface structures based on extensional flow that can explain their ridge and trough morphology as well as their down-ice persistence.

Glasser, N. F.; Gudmundsson, G. H.

2012-03-01

168

Get Close to Glaciers with Satellite Imagery.  

ERIC Educational Resources Information Center

Discusses the use of remote sensing from satellites to monitor glaciers. Discusses efforts to use remote sensing satellites of the Landsat series for examining the global distribution, mass, balance, movements, and dynamics of the world's glaciers. Includes several Landsat images of various glaciers. (TW)

Hall, Dorothy K.

1986-01-01

169

Fate of Mountain Glaciers in the Anthropocene  

E-print Network

Fate of Mountain Glaciers in the Anthropocene A Report by the Working Group Commissioned of Sciences at the Vatican, to contemplate the observed retreat of the mountain glaciers, its causes and consequences. This report resulted from a workshop in April 2011 at the Vatican. 2007 Courtesy of Glacier

Stocker, Thomas

170

Glaciers and icecaps: Storehouses of freshwater  

NSDL National Science Digital Library

Glacier: Complete description of what glaciers and icecaps are and why they are important to us. Maps show the location of glaciers and icecaps. This resource is part of the "Water Science for Schools" collection at the United States Geological Survey.

171

BIODIVERSITY Accounting for tree line shift, glacier  

E-print Network

BIODIVERSITY RESEARCH Accounting for tree line shift, glacier retreat and primary succession land cover (tree line shift, glacier retreat and primary succession) into species distribution model. Methods We fit linear mixed effects (LME) models to historical changes in forest and glacier cover

Zimmermann, Niklaus E.

172

4, 173211, 2008 Climate and glacier  

E-print Network

CPD 4, 173­211, 2008 Climate and glacier response to ENSO in subtropical Andes E. Dietze et al forum of Climate of the Past Response of regional climate and glacier ice proxies to El Ni of the European Geosciences Union. 173 #12;CPD 4, 173­211, 2008 Climate and glacier response to ENSO

Boyer, Edmond

173

2, 121, 2008 Mountain glaciers of  

E-print Network

TCD 2, 1­21, 2008 Mountain glaciers of NE Asia M. D. Ananicheva et al. Title Page Abstract The Cryosphere Discussions is the access reviewed discussion forum of The Cryosphere Mountain glaciers of NE Asia in the near future: a projection based on climate-glacier systems' interaction M. D. Ananicheva1 , A. N

Boyer, Edmond

174

Glacier variations in the Bernese Alps (Switzerland)  

E-print Network

Glacier variations in the Bernese Alps (Switzerland) ­ Reconstructions and simulations #12;#12;Glacier variations in the Bernese Alps (Switzerland) ­ Reconstructions and simulations Two Alpine glaciers over the last two centuries: a scientific view based on pictorial sources Starting

Steiner, Daniel

175

Muir Glacier and Muir Inlet 1980  

USGS Multimedia Gallery

This ship-deck-based August 1980 photograph of Muir Glacier and Muir Inlet, Glacier Bay National Park and Preserve, St. Elias Mountains, Alaska, shows the nearly 200-ft-high retreating tidewater end of Muir Glacier with part of its face capped by a few angular pinnacles of ice, called sracs....

176

Flow velocities of Alaskan glaciers.  

PubMed

Our poor understanding of tidewater glacier dynamics remains the primary source of uncertainty in sea level rise projections. On the ice sheets, mass lost from tidewater calving exceeds the amount lost from surface melting. In Alaska, the magnitude of calving mass loss remains unconstrained, yet immense calving losses have been observed. With 20% of the global new-water sea level rise coming from Alaska, partitioning of mass loss sources in Alaska is needed to improve sea level rise projections. Here we present the first regionally comprehensive map of glacier flow velocities in Central Alaska. These data reveal that the majority of the regional downstream flux is constrained to only a few coastal glaciers. We find regional calving losses are 17.1?Gt?a(-1), which is equivalent to 36% of the total annual mass change throughout Central Alaska. PMID:23857302

Burgess, Evan W; Forster, Richard R; Larsen, Christopher F

2013-01-01

177

Phytoplankton biomass andphotosynthetic competency in the summertime Mertz Glacier Region of East Antarctica  

Microsoft Academic Search

Vertical profiles of water temperature, salinity, beam transmission, density, pressure, wind speed, wind direction, phytoplankton biomass (chlorophyll a (Chl a) plus phaeophytin a), andphotosynthetic competency (by fast repetition- rate fluorometry) are presentedfor the Mertz Glacier region, East Antarctica, for a 3-week periodd uring the austral summer 2000-2001. Injection of low-salinity water from the melting of the ice pack formeda shallow

Robert D. Vaillancourt; Sara Green

2003-01-01

178

Glacier recession in Iceland and Austria  

SciTech Connect

It has been possible to measure glacier recession on the basis of Landsat data, in conjunction with comparisons of the magnitude of recession of a glacier margin with in situ measurements at fixed points along the same margin. Attention is presently given to the cases of Vatnajokull ice cap, in Iceland, and the Pasterze Glacier, in Austria, on the basis of satellite data from 1973-1987 and 1984-1990, respectively. Indications of a trend toward negative mass balance are noted. Nevertheless, while most of the world's small glaciers have been receding, some are advancing either due to local climate or the tidewater glacier cycle. 21 refs.

Hall, D.K.; Williams, R.S. Jr.; Bayr, K.J. (NASA, Goddard Space Flight Center, Greenbelt, MD (United States) USGS, Reston, VA (United States) Keene State College, NH (United States))

1992-03-01

179

Glacier recession in Iceland and Austria  

NASA Technical Reports Server (NTRS)

It has been possible to measure glacier recession on the basis of Landsat data, in conjunction with comparisons of the magnitude of recession of a glacier margin with in situ measurements at fixed points along the same margin. Attention is presently given to the cases of Vatnajokull ice cap, in Iceland, and the Pasterze Glacier, in Austria, on the basis of satellite data from 1973-1987 and 1984-1990, respectively. Indications of a trend toward negative mass balance are noted. Nevertheless, while most of the world's small glaciers have been receding, some are advancing either due to local climate or the tidewater glacier cycle.

Hall, Dorothy K.; Williams, Richard S., Jr.; Bayr, Klaus J.

1992-01-01

180

Light Iceland Glacier Recession 1973 to 2000  

NSDL National Science Digital Library

This animation shows glacier recesion at the Breidamerkurjokull glacier in Iceland. The data from 1973 is taken from Landsat 1 and the 2000 data is from Landsat 7. The Breidamerkurjokull glacier in Iceland has been measured by Landsat to be receding since 1973. The glacierologists in Iceland and here at NASAs Goddard Space Flight Center have measured the recession throughout the entire glacier and found different rates of recession in different areas. In genral, the glacier seems to be receding at about 2% annually. It is extremely controversial whether or not this recession is caused by global warming.

Lori Perkins

2001-04-09

181

Longitudinal surface structures (flowstripes) on Antarctic glaciers  

NASA Astrophysics Data System (ADS)

Longitudinal surface structures (''flowstripes'') are common on many glaciers but their origin and significance are poorly understood. In this paper we present observations of the development of these longitudinal structures from four different Antarctic glacier systems (the Lambert Glacier/Amery Ice Shelf area, outlet glaciers in the Ross Sea sector, ice-shelf tributary glaciers on the Antarctic Peninsula, and the onset zone of a tributary to the Recovery Glacier Ice Stream in the Filchner Ice Shelf area). Mapping from optical satellite images demonstrates that longitudinal surface structures develop in two main situations: (1) as relatively wide flow stripes within glacier flow units and (2) as relatively narrow flow stripes where there is convergent flow around nunataks or at glacier confluence zones. Our observations indicate that the confluence features are narrower, sharper, and more clearly defined features. They are characterised by linear troughs or depressions on the ice surface and are much more common than the former type. Longitudinal surface structures within glacier flow units have previously been explained as the surface expression of localised bed perturbations but a universal explanation for those forming at glacier confluences is lacking. Here we propose that these features are formed at zones of ice acceleration and extensional flow at glacier confluences. We provide a schematic model for the development of longitudinal surface structures based on extensional flow that can explain their ridge and trough morphology as well as their down-ice persistence.

Glasser, N. F.; Gudmundsson, G. H.

2011-11-01

182

The contribution of glacier melt to streamflow  

NASA Astrophysics Data System (ADS)

Ongoing and projected future changes in glacier volume and extent globally have led to concerns about the implications for water supplies. Glacier contributions to river discharge are not well known on a regional or global basis, nor are the populations at risk to future glacier changes. We estimate upper bounds on the fraction of river discharge attributable to glacier discharge on a monthly basis using a global hydrology model and glacier energy balance computations, and track this fraction through the global stream network. In general, our estimates of the fraction of river discharge attributable to glacier sources are lower than previously published values. Nonetheless, we estimate that globally 370 (140) million people live in river basins where glacier sources contribute at least 10% (25%) of river discharge on a seasonal basis. Most of this population is in the High Asia region.

Schaner, Neil; Voisin, Nathalie; Nijssen, Bart; Lettenmaier, Dennis P.

2012-09-01

183

The contribution of glacier melt to streamflow  

SciTech Connect

Ongoing and projected future changes in glacier extent and water storage globally have lead to concerns about the implications for water supplies. However, the current magnitude of glacier contributions to river runoff is not well known, nor is the population at risk to future glacier changes. We estimate an upper bound on glacier melt contribution to seasonal streamflow by computing the energy balance of glaciers globally. Melt water quantities are computed as a fraction of total streamflow simulated using a hydrology model and the melt fraction is tracked down the stream network. In general, our estimates of the glacier melt contribution to streamflow are lower than previously published values. Nonetheless, we find that globally an estimated 225 (36) million people live in river basins where maximum seasonal glacier melt contributes at least 10% (25%) of streamflow, mostly in the High Asia region.

Schaner, Neil; Voisin, Nathalie; Nijssen, Bart; Lettenmaier, D. P.

2012-09-13

184

The current disequilibrium of North Cascade glaciers  

NASA Astrophysics Data System (ADS)

Three lines of evidence indicate that North Cascade (Washington, USA) glaciers are currently in a state of disequilibrium. First, annual balance measured on nine glaciers yields a mean cumulative balance for the 1984-2004 period of -8.58 m water equivalent (w.e.), a net loss of ice thickness exceeding 9.5 m. This is a significant loss for glaciers that average 30-50 m in thickness, representing 18-32% of their entire volume.Second, longitudinal profiles completed in 1984 and 2002 on 12 North Cascade glaciers confirm this volume change indicating a loss of -5.7 to -6.3 m in thickness (5.0-5.6 m w.e.) between 1984 and 2002, agreeing well with the measured cumulative balance of -5.52 m w.e. for the same period. The change in thickness on several glaciers has been equally substantial in the accumulation zone and the ablation zone, indicating that there is no point to which the glacier can retreat to achieve equilibrium. Substantial thinning along the entire length of a glacier is the key indicator that a glacier is in disequilibrium.Third, North Cascade glacier retreat is rapid and ubiquitous. All 47 glaciers monitored are currently undergoing significant retreat or, in the case of four, have disappeared. Two of the glaciers where mass balance observations were begun, Spider Glacier and Lewis Glacier, have disappeared. The retreat since 1984 of eight Mount Baker glaciers that were all advancing in 1975 has averaged 297 m. These observations indicate broad regional continuity in glacial response to climate.

Pelto, Mauri S.

2006-03-01

185

Mass balance, meteorology, area altitude distribution, glacier-surface altitude, ice motion, terminus position, and runoff at Gulkana Glacier, Alaska, 1996 balance year  

USGS Publications Warehouse

The 1996 measured winter snow, maximum winter snow, net, and annual balances in the Gulkana Glacier Basin were evaluated on the basis of meteorological, hydrological, and glaciological data. Averaged over the glacier, the measured winter snow balance was 0.87 meter on April 18, 1996, 1.1 standard deviation below the long-term average; the maximum winter snow balance, 1.06 meters, was reached on May 28, 1996; and the net balance (from August 30, 1995, to August 24, 1996) was -0.53 meter, 0.53 standard deviation below the long-term average. The annual balance (October 1, 1995, to September 30, 1996) was -0.37 meter. Area-averaged balances were reported using both the 1967 and 1993 area altitude distributions (the numbers previously given in this abstract use the 1993 area altitude distribution). Net balance was about 25 percent less negative using the 1993 area altitude distribution than the 1967 distribution. Annual average air temperature was 0.9 degree Celsius warmer than that recorded with the analog sensor used since 1966. Total precipitation catch for the year was 0.78 meter, 0.8 standard deviations below normal. The annual average wind speed was 3.5 meters per second in the first year of measuring wind speed. Annual runoff averaged 1.50 meters over the basin, 1.0 standard deviation below the long-term average. Glacier-surface altitude and ice-motion changes measured at three index sites document seasonal ice-speed and glacier-thickness changes. Both showed a continuation of a slowing and thinning trend present in the 1990s. The glacier terminus and lower ablation area were defined for 1996 with a handheld Global Positioning System survey of 126 locations spread out over about 4 kilometers on the lower glacier margin. From 1949 to 1996, the terminus retreated about 1,650 meters for an average retreat rate of 35 meters per year.

March, Rod S.

2003-01-01

186

Quaternary Glaciers of New Zealand  

Microsoft Academic Search

Located in the southwestern Pacific Ocean, New Zealand's record of Quaternary glaciations, preserved in landforms and near-surface deposits, begins at the margins of modern glaciers and extends outwards geographically and backwards in time, to the last glaciation and beyond. The record becomes increasingly fragmentary into the Middle and Early Pleistocene.

D. J. A. Barrell

2011-01-01

187

Icebergs and Glaciers: Unit Outlines  

NSDL National Science Digital Library

This article assembles free resources from the Icebergs and Glaciers issue of the Beyond Penguins and Polar Bears cyberzine into a unit outline based on the 5E learning cycle framework. Outlines are provided for Grades K-2 and 3-5.

Jessica Fries-Gaither

188

MOVEMENT OF WATER IN GLACIERS  

Microsoft Academic Search

A network of passages situated along three-grain intersections enables water to percolate through temperate glacier ice. The deformability of the ice allows the passages to expand and contract in response to changes in pressure, and melting of the passage walls by heat generated by viscous dissipation and carried by above-freezing water causes the larger passages gradually to increase in size

R. L. SHREVE

1972-01-01

189

Mountain Glaciers and Ice Caps  

USGS Publications Warehouse

Projections of future rates of mass loss from mountain glaciers and ice caps in the Arctic focus primarily on projections of changes in the surface mass balance. Current models are not yet capable of making realistic forecasts of changes in losses by calving. Surface mass balance models are forced with downscaled output from climate models driven by forcing scenarios that make assumptions about the future rate of growth of atmospheric greenhouse gas concentrations. Thus, mass loss projections vary considerably, depending on the forcing scenario used and the climate model from which climate projections are derived. A new study in which a surface mass balance model is driven by output from ten general circulation models (GCMs) forced by the IPCC (Intergovernmental Panel on Climate Change) A1B emissions scenario yields estimates of total mass loss of between 51 and 136 mm sea-level equivalent (SLE) (or 13% to 36% of current glacier volume) by 2100. This implies that there will still be substantial glacier mass in the Arctic in 2100 and that Arctic mountain glaciers and ice caps will continue to influence global sea-level change well into the 22nd century.

Ananichheva, Maria; Arendt, Anthony; Hagen, Jon-Ove; Hock, Regine; Josberger, Edward G.; Moore, R. Dan; Pfeffer, William Tad; Wolken, Gabriel J.

2011-01-01

190

UV - GLACIER NATIONAL PARK MT  

EPA Science Inventory

Brewer 134 is located in Glacier NP, measuring ultraviolet solar radiation. Irradiance and column ozone are derived from this data. Ultraviolet solar radiation is measured with a Brewer Mark IV, single-monochrometer, spectrophotometer manufactured by SCI-TEC Instruments, Inc. of ...

191

Jakobshavn Glacier Ice Flow (WMS)  

NSDL National Science Digital Library

Since measurements of Jakobshavn Isbrae were first taken in 1850, the glacier has gradually receded, finally coming to rest at a certain point for the past 5 decades. However, from 1997 to 2003, the glacier has begun to recede again, this time almost doubling in speed. The finding is important for many reasons. For starters, as more ice moves from glaciers on land into the ocean, it raises sea levels. Jakobshavn Isbrae is Greenlands largest outlet glacier, draining 6.5 percent of Greenlands ice sheet area. The ice streams speed-up and near-doubling of ice flow from land into the ocean has increased the rate of sea level rise by about .06 millimeters (about .002 inches) per year, or roughly 4 percent of the 20th century rate of sea level increase. This animation shows a time-lapse sequence of the ice flowing toward the ocean. In recent years, even ice that has traditionally remained in place is now being pulled down to the edge of land.

Eric Sokolowsky

2005-03-30

192

Muir and Riggs Glaciers, Muir Inlet, Alaska - 1941  

USGS Multimedia Gallery

This northeast-looking photograph, on the southeastern side of White Thunder Ridge ,shows the lower reaches of Muir Glacier, then a large tidewater calving valley glacier, and its tributary Riggs Glacier. The sracs in the lower right-hand corner of the photograph mark Muir Glaciers te...

193

Talus rock glaciers in Scotland: Characteristics and controls on formation  

Microsoft Academic Search

Talus rock glaciers produced by creep of internal ice are common in mountains underlain by permafrost. In Scotland, relict talus rock glaciers of inferred Loch Lomond Stadial age are rare, despite widespread former permafrost. In part this reflects occupation of favourable sites by glacier ice. Outside the glacierized area, rock glacier formation was constrained by debris thickness. The debris in

Alison F. Sandeman; Colin K. Ballantyne

1996-01-01

194

Glacier area changes in Northern Eurasia  

NASA Astrophysics Data System (ADS)

Glaciers are widely recognized as key indicators of climate change. Recent evidence suggests an acceleration of glacier mass loss in several key mountain regions. Glacier recession implies landscape changes in the glacial zone, the origin of new lakes and activation of natural disaster processes, catastrophic mudflows, ice avalanches, outburst floods, etc. The absence or inadequacy of such information results in financial and human losses. A more comprehensive evaluation of glacier changes is imperative to assess ice contributions to global sea level rise and the future of water resources from glacial basins. One of the urgent steps is a full inventory of all ice bodies and their changes. The first estimation of glacier state and glacier distribution on the territory of the former Soviet Union has been done in the USSR Glacier Inventory (UGI) published in 1965-1982. The UGI is based on topographic maps and air photos and reflects the status of the glaciers in the 1940s-1970s. There is information about 28?884 glaciers with an area of 7830.75 km2 in the inventory. It covers 25 glacier systems in Northern Eurasia. In the 1980s the UGI has been transformed into digital form as a part of the World Glacier Inventory (WGI). Recent satellite data provide a unique opportunity to look again at these glaciers and to evaluate changes in glacier extent for the second part of the 20th century. About 15?000 glacier outlines for the Caucasus, Polar Urals, Pamir Alay, Tien Shan, Altai, Kamchatka and Russian Arctic have been derived from ASTER and Landsat imagery and can be used for glacier change evaluation. Results of the analysis indicate the steady trend in glacier shrinkage in all mountain regions for the second part of the 20th century. Glacier area loss for the studied regions varies from 13% (Tien Shan) to 22.3% (Polar Urals). The common driver, most likely, is an increase in summer air temperature. There is also a very large variability in the degree of individual glacier degradation, very much depending on the morphology and local meteorological conditions.

Khromova, Tatiana; Nosenko, Gennady; Kutuzov, Stanislav; Muraviev, Anton; Chernova, Ludmila

2014-01-01

195

Hasty retreat of glaciers in northern Patagonia  

NASA Astrophysics Data System (ADS)

Mapping glacier extent from optical satellite data has become a most efficient tool to create or update glacier inventories and determine glacier changes over time. A most valuable archive in this regard is the nearly 30-year time series of Landsat Thematic Mapper (TM) data that is freely available (already orthorectified) for most regions in the world from the USGS. One region with a most dramatic glacier shrinkage and a missing systematic assessment of changes, is the Palena province in Chile, located south of Puerto Montt in northern Patagonia. A major bottleneck for accurate determination of glacier changes in this region is related to the huge amounts of snow falling in this very maritime region, hiding the perimeter of glaciers throughout the year. Consequently, we found only three years with Landsat scenes that can be used to map glacier extent through time. We here present the results of a glacier change analysis from six Landsat scenes (path-rows 232-89/90) acquired in 1985, 2000 and 2011 covering the Palena district in Chile and neighbouring regions. Clean glacier ice was mapped automatically with a standard technique (TM3/TM band ratio) and manual editing was applied to remove wrongly classified lakes and to add debris-covered glacier parts. The digital elevation model (DEM) from ASTER (GDEM2) was used to derive drainage divides, determine glacier specific topographic parameters, and analyse the area changes in regard to topography. The scene from the year 2000 has the best snow conditions and was used to eliminate seasonal snow in the other two scenes by digital combination of the binary glacier masks and neighbourhood analysis. The derived mean relative area loss over the entire study area is 25%, showing a large spatial variability and a strong dependence on elevation. While small mountain glaciers at high elevations and steep slopes show only little change over the 26-year period, ice at low elevations from large valley glaciers shows a dramatic decline (area and thickness loss). Some glaciers retreated more than 3 km over this time period or even disappeared completely. Typically, these glaciers lost contact to the accumulation areas of tributaries and melted away as dead ice. Furthermore, numerous proglacial lakes formed or expanded rapidly, increasing the local hazard potential. On the other hand, some glaciers located on or near to (still active) volcanoes have also slightly advanced over the same time period. Observed trends in temperature (decreasing) are in contrast to the observed strong glacier shrinkage, indicating that also other factors must play a role.

Paul, Frank; Mlg, Nico

2014-05-01

196

Integrated research on mountain glaciers: Current status, priorities and future prospects  

E-print Network

Integrated research on mountain glaciers: Current status, priorities and future prospects Lewis A: Glaciation Glaciers Mountains Glaciology Geochronology Modeling Mountain glaciers are sensitive probes and to predict future changes. Furthermore, glaciers can constitute hazards, including: glacier outburst floods

Roe, Gerard

197

5. GLACIER POINT ROAD VIEW AT SENTINEL DOME PARKING AREA. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. GLACIER POINT ROAD VIEW AT SENTINEL DOME PARKING AREA. LOOKING E. GIS: N-37 42 43.8 / W-119 35 12.1 - Glacier Point Road, Between Chinquapin Flat & Glacier Point, Yosemite Village, Mariposa County, CA

198

1. PARKING LOT AT GLACIER POINT. HALF DOME AT CENTER ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. PARKING LOT AT GLACIER POINT. HALF DOME AT CENTER REAR. LOOKING NE. GIS: N-36 43 45.8 / W-119 34 14.1 - Glacier Point Road, Between Chinquapin Flat & Glacier Point, Yosemite Village, Mariposa County, CA

199

Calendar-dated, early 'Little Ice Age' glacier advance at Robson Glacier, British Columbia, Canada  

Microsoft Academic Search

Dendrochronological studies at Robson and Bennington Glaciers have provided the first calendar dating of an early 'Little Ice Age' glacier advance in North America. Dates derived from in-situ stumps indicate that Robson Glacier began over-riding forest between c. AD 1142 and 1150 and continued until at least AD 1350. The highest rates of glacier advance (c. 3.8 m yr-1 )

B. H. Luckman

1995-01-01

200

Attribution of glacier fluctuations to climate change  

NASA Astrophysics Data System (ADS)

Glacier retreat is a worlwide phenomenon, which started around the middle of the 19th century. During the period 1800-1850 the number of retreating and advancing glaciers was roughly equal (based on 42 records from different continents). During the period 1850-1900 about 92% of all mountain glaciers became shorter (based on 65 records). After this, the percentage of shrinking glaciers has been around 90% until the present time. The glacier signal is rather coherent over the globe, especially when surging and calving glaciers are not considered (for such glaciers the response to climate change is often masked by length changes related to internal dynamics). From theoretical studies as well as extensive meteorological work on glaciers, the processes that control the response of glaciers to climate change are now basically understood. It is useful to make a difference between geometric factors (e.g. slope, altitudinal range, hypsometry) and climatic setting (e.g. seasonal cycle, precipitation). The most sensitive glaciers appear to be flat glaciers in a maritime climate. Characterizing the dynamic properties of a glacier requires at least two quantities: the climate sensitivity, expressing how the equilibrium glacier state depends on the climatic conditions, and the response time, indicating how fast a glacier approaches a new equilibrium state after a stepwise change in the climatic forcing. These quantities can be estimated from relatively simple theory, showing that differences among glaciers are substantial. For larger glaciers, climate sensitivities (in terms of glacier length) vary from 1 to 8 km per 100 m change in the equilibrium-line altitude. Response times are mainly in the range of 20 to 200 years, with most values between 30 and 80 years. Changes in the equilibrium-line altitude or net mass balance of a glacier are mainly driven by fluctuations in air temperature, precipitation, and global radiation. Energy-balance modelling for many glaciers shows that, globally speaking, a 1 K temperature increase has the same effect as a ~25% decrease in precipitation, or a ~15% increase in global radiation. However, the relative importance of these drivers depends significantly on the climatic setting (notably continentality). In this contribution I will give a brief survey of glacier fluctuations over the past few centuries, and provide arguments that on the worldwide scale air temperature must have been the main driver of these fluctuations. A history of global mean temperature that explains the observed glacier fluctuations best will be discussed. On smaller spatial (regional) and temporal (decades) scales, changes in precipitation become important. Both with respect to the attribution problem (what caused the glacier fluctuations in the past?) and the projection issue (what will happen in the next 100 years?), it is important that many more glaciers are explicitly studied with numerical models. I will argue that for non-calving glaciers these models can be relatively simple.

Oerlemans, J.

2012-04-01

201

Brief Communication: Getting Greenland's glaciers right - a new dataset of all official Greenlandic glacier names  

NASA Astrophysics Data System (ADS)

With this new dataset we wish to give the researcher working with Greenlandic glaciers the proper tool to finding the correct name for glaciers and ice caps in Greenland, as well as to locate glaciers described in the historic literature with the old Greenlandic orthography.

Bjrk, A. A.; Kruse, L. M.; Michaelsen, P. B.

2015-03-01

202

115GLACIERS AND ICE CAPSCHAPTER 6B Glaciers and Ice Caps  

E-print Network

. Chinn New Zealand (Alpine and Polar Processes, New Zealand); Andrew G. Fountain USA and Canada115GLACIERS AND ICE CAPSCHAPTER 6B 6B Glaciers and Ice Caps Michael Zemp (lead author, Department, University of Zurich, Switzerland) Contributing Authors for Regional Perspectives and Glacier Hazards

Fountain, Andrew G.

203

The GAMDAM Glacier Inventory: a quality controlled inventory of Asian glaciers  

NASA Astrophysics Data System (ADS)

We present a new glacier inventory for the high mountain Asia named "Glacier Area Mapping for Discharge from the Asian Mountains" (GAMDAM). Glacier outlines were delineated manually using more than 226 Landsat ETM+ scenes from the period 1999-2003, in conjunction with a digital elevation model (DEM) and high-resolution Google Earth imagery. Geolocations are consistent between the Landsat imagery and DEM due to systematic radiometric and geometric corrections made by the United States Geological Survey. We performed repeated delineation tests and rigorous peer review of all scenes used in order to maintain the consistency and quality of the inventory. Our GAMDAM Glacier Inventory (GGI) includes 82776 glaciers covering a total area of 87507 13126 km2 in the high mountain Asia. Thus, our inventory represents a greater number (+4%) of glaciers but significantly less surface area (-31%) than a recent global glacier inventory (Randolph Glacier Inventory, RGI). The employed definition of the upper boundaries of glaciers, glacier recession since the 1970s, and misinterpretation of seasonal snow cover are likely causes of discrepancies between the inventories, though it is difficult to evaluate these effects quantitatively. The GGI will help improve the temporal consistency of the RGI, which incorporated glacier outlines from the 1970s for the Tibetan Plateau, and will provide new opportunities to study Asian glaciers.

Nuimura, T.; Sakai, A.; Taniguchi, K.; Nagai, H.; Lamsal, D.; Tsutaki, S.; Kozawa, A.; Hoshina, Y.; Takenaka, S.; Omiya, S.; Tsunematsu, K.; Tshering, P.; Fujita, K.

2014-06-01

204

Drainage events from a glacier-dammed lake, Bear Glacier, Alaska: Remote sensing and field observations  

NASA Astrophysics Data System (ADS)

We investigated drainage events from a glacier-dammed lake on Bear Glacier, Alaska, and associated outburst floods and hazards. The glacier-dammed lake, which we call Ice Lake, is 17.5 km up-glacier from Bear Glacier's terminus at Bear Glacier Lake. We combine field observations and remote sensing to examine temporal changes in the size of Ice Lake, the frequency and timing of its drainage, and down-glacier propagation of its outburst floods. We found that in recent years, Ice Lake has likely drained every year or two, in late summer or fall (August-October), with outbursts generally following the damming of sufficient water to create a lake area of between 0.35 and 0.5 km2. Ice Lake has migrated downvalley to the south since the 1990s, likely as a result of thinning of the glacier that dams it. In situ measurements of a drainage event in October 2010 showed that Ice Lake drained over a period of days, which manifested at Bear Glacier Lake as a gradual, multiday increase and then decrease in water levels. Glacial lake outburst flooding at Bear Glacier creates risks for sea kayakers in Bear Glacier Lake and may be relevant to understanding the effects of climate warming on glacier-dammed and proglacial lakes.

Wilcox, A. C.; Wade, A. A.; Evans, E. G.

2014-09-01

205

Glacier Surge Mechanism: 1982-1983 Surge of Variegated Glacier, Alaska  

Microsoft Academic Search

The hundredfold speedup in glacier motion in a surge of 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

Barclay Kamb; C. F. Raymond; W. D. Harrison; Hermann Engelhardt; K. A. Echelmeyer; N. Humphrey; M. M. Brugman; T. Pfeffer

1985-01-01

206

GLACIER HAZARDS AT BELVEDERE GLACIER AND THE MONTE ROSA EAST FACE, ITALIAN ALPS: PROCESSES AND MITIGATION  

E-print Network

, and confront the responsible authorities with complex problems without precedent in the European Alps I / 67 GLACIER HAZARDS AT BELVEDERE GLACIER AND THE MONTE ROSA EAST FACE, ITALIAN ALPS and Giorgio Viazzo7 ABSTRACT In summer 2001, the Belvedere glacier, Macugnaga, Italian Alps, started a surge

Kb, Andreas

207

Google Earth Tours of Glacier Change  

NSDL National Science Digital Library

To prepare for this assignment students have already used Google Earth to examine beach erosion, but they have not yet created any new content with Google Earth. Students are already competent navigators and are accustomed to the perspective views used in Google Earth. In this assignment students first go through a prepared Google Earth tour on Juneau Icefield glaciers, and answer questions about glacier features. Then students create their own Google Earth tour, using placemarks to identify key features of their glacier.

Mauri Pelto

208

Sensitivity analysis of glacier systems to climate warming in China  

Microsoft Academic Search

Data of 44 glacier systems in China used in this paper were obtained from Chinese Glacier Inventories and the meteorological\\u000a data were got from Meteorological Atlas of Plateau of west China. Based on the statistical analysis and functional model simulation\\u000a results of the 44 glacier systems in China, the glacier systems were divided into extremely-sensitive glacier system, semi-sensitive\\u000a glacier system,

Xin Wang; Zichu Xie; Qiaoyuan Li; Shuhong Wang; Lei Cheng

2008-01-01

209

Bering Glacier resumes its surge  

NASA Astrophysics Data System (ADS)

Bering Glacier has started to surge again following a 7-month period of minor retreat and near-stagnation. Part of the terminus advanced about 750 m between May 19 and June 1.Beringthe largest surging temperate glacier on Earthrecently experienced a major, 17-month-long surge that ended in September 1994. That surge displaced the terminus by a maximum of about 9 km and caused a substantial increase in iceberg production. It also covered the islands within Vitus Lake completely or partially with ice [Eos, 74, 321-322, 521; Eos, 75, 549] and caused significant changes in the lake's size, bathymetry, hydrology, and water chemistry. The latest surge is overriding two of these islands, which are home to many species of waterfowl, including the endangered dusky snow goose, at the peak of the nesting season.

Molnia, Bruce F.

210

Glac Modeled Glacier Change Animation  

NSDL National Science Digital Library

Animation of Modeled Climate-Induced Glacier Change in Glacier National Park, 1850- 2100. The simulation reflects the predicted exponential rise in atmospheric CO2 concentrations, a 2xCO2 "global warming" scenario, with a concurrent warming of 2-3 degrees centigrade (4-5 degrees Fahrenheit) by the year 2050. In addition it assumes that precipitation, primarily in the form of rain, will increase over the same time period about 10 percent (based on the research of Dr. Steven Running, University of Montana). The animation view of the Blackfoot-Jackson basin along the Continental Divide, includes Gunsight Lake in the foreground and a portion of Lake Ellen Wilson visible over Gunsight Pass.

Myrna H. P. Hall

211

Ice thickness, ablation, and other glaciological measurements on upper Fremont Glacier, Wyoming  

USGS Publications Warehouse

Glaciological investigations of the Upper Fremont Glacier in the Wind River Range of Wyoming were conducted during 1990-1991. The glaciological data will provide baseline information for monitoring future changes to the glacier and support ongoing research utilizing glacial-ice-core composition to reconstruct paleoenvironmental records. Ice thickness, determined by radio-echo sounding, ranged from 60 to 172 m in the upper half of the glacier. Radio-echo sounding of ice thickness at one point was confirmed by drilling 159.7 m to bedrock. Annual ablation (including snow, firn, and ice) measured for the 1990-1991 period averaged about 0.93 m/a. Surface ice velocity and direction were monitored from July 1990 to August 1991. Ice velocity decreased in a downslope direction. The largest measured velocity was about 3.1 m/a and the smallest was 0.8 m/a. -from Authors

Naftz, D.L.; Smith, M.E.

1993-01-01

212

Step-wise changes in glacier flow speed coincide with calving and glacial earthquakes at Helheim Glacier, Greenland  

E-print Network

[1] Geodetic observations show several large, sudden increases in flow speed at Helheim Glacier, one of Greenland's largest outlet glaciers, during summer, 2007. These step-like accelerations, detected along the length of the glacier, coincide...

Nettles, M.; Larsen, T.B.; Elosegui, P.; Hamilton, Gordon S.; Stearns, Leigh; Ahlstrom, A.P.; Davis, J.L.; Anderson, M.L.; de Juan, J.; Khan, S.A.; Stenseng, L.; Ekstrom, G.; Forsberg, R.

2008-12-30

213

Fluffy Snow to Glacier Ice  

NSDL National Science Digital Library

In this activity, students build on their growing knowledge of ice and glacier growth. The students examine images of core samples and make observations about the decreasing size of gas bubbles with increasing depth in the core. The students model permeability. From this experiment, they will develop an understanding of the movement of air through snow and ice and why this information is critical to researchers studying the past climate of our Earth.

Sharon Shutey

214

Antarctica: measuring glacier velocity from satellite images  

SciTech Connect

Many Landsat images of Antarctica show distinctive flow and crevasse features in the floating part of ice streams and outlet glaciers immediately below their grounding zones. Some of the features, which move with the glacier or ice stream, remain visible over many years and thus allow time-lapse measurements of ice velocities. Measurements taken from Landsat images of features on Byrd Glacier agree well with detailed ground and aerial observations. The satellite-image technique thus offers a rapid and cost-effective method of obtaining average velocities, to a first order of accuracy, of many ice streams and outlet glaciers near their termini.

Lucchitta, B.K.; Ferguson, H.M.

1986-11-28

215

Antarctica: Measuring glacier velocity from satellite images  

USGS Publications Warehouse

Many Landsat images of Antarctica show distinctive flow and crevasse features in the floating part of ice streams and outlet glaciers immediately below their grounding zones. Some of the features, which move with the glacier or ice stream, remain visible over many years and thus allow time-lapse measurements of ice velocities. Measurements taken from Landsat images of features on Byrd Glacier agree well with detailed ground and aerial observations. The satellite-image technique thus offers a rapid and cost-effective method of obtaining average velocities, to a first order of accuracy, of many ice streams and outlet glaciers near their termini.

Lucchitta, B.K.; Ferguson, H.M.

1986-01-01

216

Fast recession of a west antarctic glacier  

PubMed

Satellite radar interferometry observations of Pine Island Glacier, West Antarctica, reveal that the glacier hinge-line position retreated 1.2 +/- 0.3 kilometers per year between 1992 and 1996, which in turn implies that the ice thinned by 3.5 +/- 0.9 meters per year. The fast recession of Pine Island Glacier, predicted to be a possible trigger for the disintegration of the West Antarctic Ice Sheet, is attributed to enhanced basal melting of the glacier floating tongue by warm ocean waters. PMID:9677195

Rignot

1998-07-24

217

Internationally coordinated glacier monitoring: strategy and datasets  

NASA Astrophysics Data System (ADS)

Internationally coordinated monitoring of long-term glacier changes provide key indicator data about global climate change and began in the year 1894 as an internationally coordinated effort to establish standardized observations. Today, world-wide monitoring of glaciers and ice caps is embedded within the Global Climate Observing System (GCOS) in support of the United Nations Framework Convention on Climate Change (UNFCCC) as an important Essential Climate Variable (ECV). The Global Terrestrial Network for Glaciers (GTN-G) was established in 1999 with the task of coordinating measurements and to ensure the continuous development and adaptation of the international strategies to the long-term needs of users in science and policy. The basic monitoring principles must be relevant, feasible, comprehensive and understandable to a wider scientific community as well as to policy makers and the general public. Data access has to be free and unrestricted, the quality of the standardized and calibrated data must be high and a combination of detailed process studies at selected field sites with global coverage by satellite remote sensing is envisaged. Recently a GTN-G Steering Committee was established to guide and advise the operational bodies responsible for the international glacier monitoring, which are the World Glacier Monitoring Service (WGMS), the US National Snow and Ice Data Center (NSIDC), and the Global Land Ice Measurements from Space (GLIMS) initiative. Several online databases containing a wealth of diverse data types having different levels of detail and global coverage provide fast access to continuously updated information on glacier fluctuation and inventory data. For world-wide inventories, data are now available through (a) the World Glacier Inventory containing tabular information of about 130,000 glaciers covering an area of around 240,000 km2, (b) the GLIMS-database containing digital outlines of around 118,000 glaciers with different time stamps and (c) the Randolph Glacier Inventory (RGI), a new and globally complete digital dataset of outlines from about 180,000 glaciers with some meta-information, which has been used for many applications relating to the IPCC AR5 report. Concerning glacier changes, a database (Fluctuations of Glaciers) exists containing information about mass balance, front variations including past reconstructed time series, geodetic changes and special events. Annual mass balance reporting contains information for about 125 glaciers with a subset of 37 glaciers with continuous observational series since 1980 or earlier. Front variation observations of around 1800 glaciers are available from most of the mountain ranges world-wide. This database was recently updated with 26 glaciers having an unprecedented dataset of length changes from from reconstructions of well-dated historical evidence going back as far as the 16th century. Geodetic observations of about 430 glaciers are available. The database is completed by a dataset containing information on special events including glacier surges, glacier lake outbursts, ice avalanches, eruptions of ice-clad volcanoes, etc. related to about 200 glaciers. A special database of glacier photographs contains 13,000 pictures from around 500 glaciers, some of them dating back to the 19th century. A key challenge is to combine and extend the traditional observations with fast evolving datasets from new technologies.

Hoelzle, Martin; Armstrong, Richard; Fetterer, Florence; Grtner-Roer, Isabelle; Haeberli, Wilfried; Kb, Andreas; Kargel, Jeff; Nussbaumer, Samuel; Paul, Frank; Raup, Bruce; Zemp, Michael

2014-05-01

218

Subglacial drainage processes at a High Arctic polythermal valley glacier  

E-print Network

Glacier, Ellesmere Island, Canada, were designed to investigate the character of the subglacial drainage, polythermal valley glacier situated in eastern Ellesmere Island, Nunavut, Canada (Fig. 1). The specific

219

Geographical variations in Sr and Nd isotopic ratios of cryoconite on Asian glaciers  

NASA Astrophysics Data System (ADS)

Cryoconite is a dark-coloured surface dust deposited on glaciers that consists of wind-blown mineral particles, as well as organic matter derived from microbes living on glaciers. In this paper, we analyse the Sr and Nd isotopic ratios of four mineral fractions (i.e., the saline, carbonate, phosphate, and silicate mineral fractions), as well as the organic fraction, of cryoconite samples obtained from six Asian glaciers (the Altai, Pamir, Tien Shan, Qillian Shan, and Himalayan regions), and discuss their geographical variations in terms of the geological origins of the mineral particles and the biogeochemical processes on the glaciers. The silicate mineral fraction showed lower Sr and higher Nd ratios for the glaciers located to the north (Altai, 87Sr/86Sr: 0.713?490-0.715?284, ?Nd(0): -6.4 to -5.6), while higher Sr and lower Nd ratios for the glaciers located to the south (Himalayas, 87Sr/86Sr: 0.740?121-0.742?088, ?Nd(0): -16.4 to -15.7) the ratios were similar to those of desert sand, loess, and river sediments in the respective regions of the glaciers. This result suggests that the silicate minerals within the cryoconites were derived from different sources depending on the geographical locations of the glaciers. The isotopic ratios of the saline, carbonate, and phosphate mineral fractions were distinct from those of the silicate fraction, and were similar to those of evaporites and apatite deposits from the Asian deserts, but also varied geographically, indicating that they are likely to reflect their geological origin. The Sr isotopic ratios of the organic fraction were similar to those of the saline and carbonate fractions from glaciers in the central area (Tien Shan and Qillian Shan), but were higher than those of the saline and carbonate fractions, and lower than the phosphate mineral fraction, in the northern and southern areas. The ratios of organic fraction may be determined from the mixing ratio of calcium sources incorporated by microbes on the glaciers.

Nagatsuka, Naoko; Takeuchi, Nozomu; Nakano, Takanori; Shin, Kicheol; Kokado, Emi

2014-04-01

220

Cloud effects on the surface energy and mass balance of Brewster Glacier, New Zealand  

NASA Astrophysics Data System (ADS)

A thorough understanding of the influence of clouds on glacier surface energy balance (SEB) and surface mass balance (SMB) is critical for forward and backward modelling of glacier-climate interactions. A validated 22 month time series of SEB/SMB was constructed for the ablation zone of the Brewster Glacier, using high quality radiation data to carefully evaluate SEB terms and define clear-sky and overcast conditions. A fundamental change in glacier SEB in cloudy conditions was driven by increased effective sky emissivity and surface vapour pressure, rather than the minimal change in air temperature and wind speed. During overcast conditions, positive net longwave radiation and latent heat fluxes allowed melt to be maintained through a much greater length of time compared to clear-sky conditions, and led to similar melt in each sky condition. The sensitivity of SMB to changes in air temperature was greatly enhanced in overcast compared to clear-sky conditions due to more frequent melt and the occurrence of precipitation, which enabled a strong accumulation-albedo feedback. During the spring and autumn seasons, the sensitivity during overcast conditions was strongest. There is a need to include the effects of atmospheric moisture (vapour, cloud and precipitation) on melt processes when modelling glacier-climate interactions.

Conway, J. P.; Cullen, N. J.

2015-02-01

221

Glaciers. Attribution of global glacier mass loss to anthropogenic and natural causes.  

PubMed

The ongoing global glacier retreat is affecting human societies by causing sea-level rise, changing seasonal water availability, and increasing geohazards. Melting glaciers are an icon of anthropogenic climate change. However, glacier response times are typically decades or longer, which implies that the present-day glacier retreat is a mixed response to past and current natural climate variability and current anthropogenic forcing. Here we show that only 25 35% of the global glacier mass loss during the period from 1851 to 2010 is attributable to anthropogenic causes. Nevertheless, the anthropogenic signal is detectable with high confidence in glacier mass balance observations during 1991 to 2010, and the anthropogenic fraction of global glacier mass loss during that period has increased to 69 24%. PMID:25123485

Marzeion, Ben; Cogley, J Graham; Richter, Kristin; Parkes, David

2014-08-22

222

Latest Pleistocene advance of alpine glaciers in the southwestern Uinta Mountains, Utah, USA: Evidence for the influence of local moisture sources  

Microsoft Academic Search

Cosmogenic surface-exposure Be-10 dating of Last Glacial Maximum (LGM) moraines indicates that glaciers in the southwestern Uinta Mountains remained at their maximum positions until ca. 16.8 +\\/- 0.7 ka, similar to 2 k.y. after glaciers in the neighboring Wind River Range and Colorado Rockies began to retreat. The timing of the local LGM in the southwestern Uintas overlaps with both

Jeffrey S. Munroe; Benjamin J. C. Laabs; Jeremy D. Shakun; Brad S. Singer; David M. Mickelson; Kurt A. Refsnider; Marc W. Caffee

2006-01-01

223

A field and glacier modelling based approach to determine the timing and extent of glaciation in southern Africa  

NASA Astrophysics Data System (ADS)

Moraines identified at high-altitude sites in southern Africa and dated to the last glacial maximum (LGM) indicate that the climate in this region was cold enough to support glaciers. Small glaciers are very sensitive to changes in temperature and precipitation and the identification of LGM moraines in southern Africa has important palaeoclimatic implications concerning the magnitude of temperature change and the seasonality of precipitation during the last glacial cycle. This paper presents a refined time-frame for likely glaciations based on surface exposure dating using Cl-36 at sites in Lesotho and reports results of a 2D glacier energy balance and ice flow modelling approach (Plummer and Phillips, 2003) to evaluate the most likely climatic scenarios associated with mapped moraine limits. Samples for surface exposure dating were collected from glacially eroded bedrock at several locations and yield ages within the timescale of the LGM. Scatter in the ages may be due to insufficient erosion of the bedrock surface due to the small and relatively thin nature of the glaciers. To determine the most likely climatic conditions that may have caused the glaciers to reach their mapped extent, we use a glacier-climate model, driven by data from local weather stations and a 30m (ASTER) DEM (sub-sampled to 10m) representation of the topographic surface. The model is forced using modern climate data for primary climatic controls (temperature and precipitation) and for secondary climatic parameters (relative humidity, cloudiness, wind speed). Various sensitivity tests were run by dropping temperature by small increments and by varying the amount of precipitation and its seasonality relative to present-day values. Results suggest that glaciers could have existed in the Lesotho highlands with a temperature depression of ~5-6 C and that the glaciers were highly sensitive to small changes in temperature. The additional accumulation of mass through wind redistribution appears to have been important at all but a few sites, suggesting that this must be taken into account when trying to determine a regional climate signal from small glaciers. Our dating and glacier-climate model simulations reinforce the idea that small glaciers existed in the Lesotho Highlands during the LGM, under climatic scenarios that are consistent with other proxy records. Plummer, M.A. and Phillips, F.M. (2003) 2-D numerical model of snow/ice energy balance and ice flow for paleoclimatic interpretation of glacial geomorphic features. Quaternary Science Reviews, 22, 1389-1406.

Mills, Stephanie C.; Rowan, Ann V.; Barrow, Timothy T.; Plummer, Mitchell A.; Smith, Michael; Grab, Stefan W.; Carr, Simon J.; Fifield, L. Keith

2014-05-01

224

Himalayan glacier retreat delayed by debris cover  

Microsoft Academic Search

Variable retreat rates and paucity of mass-balance data complicate a coherent picture of the current state and future fate of Himalayan glaciers. We report frontal changes and remotely-sensed surface velocities from >250 glaciers in the greater Himalayan realm (Hindu Kush, Karakoram, Himalaya, West Kunlun Shan) between 2000 and 2008 that provide evidence for widespread meltdown, which is obscured by debris

D. Scherler; B. Bookhagen; M. R. Strecker

2010-01-01

225

Microbial biodiversity in glacier-fed streams  

PubMed Central

While glaciers become increasingly recognised as a habitat for diverse and active microbial communities, effects of their climate change-induced retreat on the microbial ecology of glacier-fed streams remain elusive. Understanding the effect of climate change on microorganisms in these ecosystems is crucial given that microbial biofilms control numerous stream ecosystem processes with potential implications for downstream biodiversity and biogeochemistry. Here, using a space-for-time substitution approach across 26 Alpine glaciers, we show how microbial community composition and diversity, based on 454-pyrosequencing of the 16S rRNA gene, in biofilms of glacier-fed streams may change as glaciers recede. Variations in streamwater geochemistry correlated with biofilm community composition, even at the phylum level. The most dominant phyla detected in glacial habitats were Proteobacteria, Bacteroidetes, Actinobacteria and Cyanobacteria/chloroplasts. Microorganisms from ice had the lowest ? diversity and contributed marginally to biofilm and streamwater community composition. Rather, streamwater apparently collected microorganisms from various glacial and non-glacial sources forming the upstream metacommunity, thereby achieving the highest ? diversity. Biofilms in the glacier-fed streams had intermediate ? diversity and species sorting by local environmental conditions likely shaped their community composition. ? diversity of streamwater and biofilm communities decreased with elevation, possibly reflecting less diverse sources of microorganisms upstream in the catchment. In contrast, ? diversity of biofilms decreased with increasing streamwater temperature, suggesting that glacier retreat may contribute to the homogenisation of microbial communities among glacier-fed streams. PMID:23486246

Wilhelm, Linda; Singer, Gabriel A; Fasching, Christina; Battin, Tom J; Besemer, Katharina

2013-01-01

226

Using Metaphorical Models for Describing Glaciers  

ERIC Educational Resources Information Center

To date, there has only been little conceptual change research regarding conceptions about glaciers. This study used the theoretical background of embodied cognition to reconstruct different metaphorical concepts with respect to the structure of a glacier. Applying the Model of Educational Reconstruction, the conceptions of students and scientists

Felzmann, Dirk

2014-01-01

227

Muir Glacier and Muir Inlet 2003  

USGS Multimedia Gallery

This photo was taken in September 2003; in the 23 years between photographs, Muir Glacier has retreated more than a mile and ceased to have a tidewater terminus. Since 1980, Muir Glacier has thinned by more than 600 ft, permitting a view of a mountain with a summit elevation of greater than 4000 ft,...

228

Glaciers in 21st Century Himalayan Geopolitics  

Microsoft Academic Search

Glaciers are ablating rapidly the world over. Nowhere are the rates of retreat and downwasting greater than in the Hindu Kush-Himalaya (HKH) region. It is estimated that over the next century, 40,000 square kilometers of present glacier area in the HKH region will become ice free. Most of this area is in major valleys and the lowest glaciated mountain passes.

J. S. Kargel; R. Wessels; H. H. Kieffer

2002-01-01

229

Early Holocene and Younger Dryas age glacier advances in Patagonia  

NASA Astrophysics Data System (ADS)

Reliable dating of Southern Hemisphere glacier fluctuations since the Last Glacial Maximum (LGM) is crucial to resolving debates about millennial-scale climate change. Here we present 10Be dates for lateral, valley-mouth and cross-valley moraines formed between the contemporary South American North Patagonian Icefield (NPI) and its LGM position in four separate valleys around 47oS. This is an area of climate sensitivity, near the core of the precipitation-bearing southern westerly winds (SWW). The dates indicate that outlet glaciers from an expanded NPI advanced to form large moraines at 10.8 0.5 / 11.0 0.6, 11.2 0.6, 11.5 0.6 and 12.5 0.7 ka (Putnam southern hemisphere production rates and Dunai scaling scheme, zero-erosion). The first four ages are statistically indistinguishable and probably represent a single, regional ice advance. With a likely assumed boulder erosion rate of 2mm/ka, these ages become 11.0 0.5 / 11.2 0.6, 11.5 0.6, 11.7 0.6 and 12.8 0.7 ka. With a higher (less likely) assumed boulder erosion rate of 10mm/ka these ages become 12.0 0.5 / 12.1 0.6, 12.4 0.6, 12.8 0.6 and 14.0 0.7 ka. The dates indicate that glaciers in Patagonia were larger during these times than at any point since the LGM and provide evidence in Patagonia for glacier advances during the very early Holocene, around the time of the European Younger Dryas (12.9 to 11.7 ka) and the Antarctic Cold Reversal (ACR; 14.5 to 12.9 ka). Although palaeoclimatic records from this area are often contradictory, these glacier advances were probably associated with a period of regionally increased precipitation related to the changes in the position of the SWW or meltwater pulses associated with the ACR.

Glasser, N. F.; Harrison, S.; Schnabel, C.; Fabel, D.; Jansson, K.

2012-12-01

230

The length of the glaciers in the world - a straightforward method for the automated calculation of glacier center lines  

NASA Astrophysics Data System (ADS)

Glacier length is an important measure of glacier geometry but global glacier inventories are mostly lacking length data. Only recently semi-automated approaches to measure glacier length have been developed and applied regionally. Here we present a first global assessment of glacier length using a fully automated method based on glacier surface slope, distance to the glacier margins and a set of trade-off functions. The method is developed for East Greenland, evaluated for the same area as well as for Alaska, and eventually applied to all ∼200 000 glaciers around the globe. The evaluation highlights accurately calculated glacier length where DEM quality is good (East Greenland) and limited precision on low quality DEMs (parts of Alaska). Measured length of very small glaciers is subject to a certain level of ambiguity. The global calculation shows that only about 1.5% of all glaciers are longer than 10 km with Bering Glacier (Alaska/Canada) being the longest glacier in the world at a length of 196 km. Based on model output we derive global and regional area-length scaling laws. Differences among regional scaling parameters appear to be related to characteristics of topography and glacier mass balance. The present study adds glacier length as a central parameter to global glacier inventories. Global and regional scaling laws might proof beneficial in conceptual glacier models.

Machguth, H.; Huss, M.

2014-05-01

231

Glaciers in 21st Century Himalayan Geopolitics  

NASA Astrophysics Data System (ADS)

Glaciers are ablating rapidly the world over. Nowhere are the rates of retreat and downwasting greater than in the Hindu Kush-Himalaya (HKH) region. It is estimated that over the next century, 40,000 square kilometers of present glacier area in the HKH region will become ice free. Most of this area is in major valleys and the lowest glaciated mountain passes. The existence and characteristics of glaciers have security impacts, and rapidly changing HKH glaciers have broad strategic implications: (1) Glaciers supply much of the fresh water and hydroelectric power in South and Central Asia, and so glaciers are valuable resources. (2) Shared economic interests in water, hydroelectricity, flood hazards, and habitat preservation are a force for common cause and reasoned international relations. (3) Glaciers and their high mountains generally pose a natural barrier tending to isolate people. Historically, they have hindered trade and intercultural exchanges and have protected against aggression. This has further promoted an independent spirit of the region's many ethnic groups. (4) Although glaciers are generally incompatible with human development and habitation, many of the HKH region's glaciers and their mountains have become sanctuaries and transit routes for militants. Siachen Glacier in Kashmir has for 17 years been "the world's highest battlefield," with tens of thousands of troops deployed on both sides of the India/Pakistan line of control. In 1999, that conflict threatened to trigger all-out warfare, and perhaps nuclear warfare. Other recent terrorist and military action has taken place on glaciers in Kyrgyzstan and Tajikistan. As terrorists are forced from easily controlled territories, many may tend to migrate toward the highest ground, where definitive encounters may take place in severe alpine glacial environments. This should be a major concern in Nepali security planning, where an Army offensive is attempting to reign in an increasingly robust and brutal Maoist insurgency. (5) Glacier lakes are in many cases very fragile and their natural dams routinely rupture, causing devastating floods. A rising regional terrorist threat in several countries could target these dams and precipitate calamitous and terrifying results. (6) Over the next century, retreating glaciers may open new corridors for trade and human migration across the Himalaya and pave the way for possible new economic, military and political alliances in the region. (7) Glacier retreat might open new sanctuaries for terrorists and open new corridors for possible ground-based military offensive action across the HKH ranges. The documentation of glacier characteristics that may influence their trafficability, and projections of future glacier extent and behavior are relevant to wide ranging concerns of the region's inhabitants. Satellite remote sensing and mapping of glaciers is one approach to defining and monitoring the problems and opportunities presented by HKH glaciers. Global Land Ice Measurements from Space (GLIMS) is a joint USGS/NASA Pathfinder project that has formed a global consortium of glaciologists in several regional centers that are mapping and monitoring the HKH glaciers using repeat-pass ASTER and Landsat ETM+ data. We are currently building a comprehensive satellite multispectral image and GIS database that is providing detailed information on the state and rates of change of each glacier in the HKH region and other areas of the world. Merging these results with DEMs allows a predictive capability that could be useful in policy development and security planning.

Kargel, J. S.; Wessels, R.; Kieffer, H. H.

2002-05-01

232

Iceland Glacier Recession 1997 to 2000  

NSDL National Science Digital Library

This animation is a close up zoom into largest area of glacier recesion at the Breidamerkurjokull glacier in Iceland. The data from 1997 is taken from Landsat 5 and the 2000 data is from Landsat 7. The Breidamerkurjokull glacier in Iceland has been measured by Landsat to be receding since 1973. In 1997, Landsat 5 took several other images of the glacier. It was thought by some glacierologists that this particular glacier was receding quicker in the late 1990s than it did in the late 1980s or 1970s. After careful analysis Goddards Glacierologist, Dorothy Hall, concluded that the recession from 1997 to 2000 occurs at a similar rate to the recession between 1973 and 2000. It is extremely controversial whether or not this recession is caused by global warming.

Lori Perkins

2001-04-09

233

Mapping Glacier Data and Photographs via GeoServer and Virtual Globes  

Microsoft Academic Search

Two extensively used glacier data sets include the World Glacier Inventory and the Glacier Photograph Collection. Both data sets are hosted at the National Snow and Ice Data Center in Boulder, Colorado. The World Glacier Inventory encompasses over 100,000 records of glacier data and the Glacier Photograph Collection houses approximately 9,000 digitized photographs. The online Glacier Photograph Collection has doubled

L. M. Ballagh; I. Wang; A. Wallace

2008-01-01

234

Geomicrobiology of a Supraglacial Stream on the Cotton Glacier, Victoria Land, Antarctica.  

NASA Astrophysics Data System (ADS)

The Cotton Glacier lies in the Transantarctic Mountains north of Cape Roberts and has a limited catchment area in the Clare and St. Johns ranges, but receives a large amount of sedimentary deposits from surrounding areas. The bedrock geology of the area is dominated by basement granite and Ferrar dolerite sills, with minor amounts of amphibolite and schist sandwiched between granite bodies. A unique fluvial system forms on the Cotton Glacier as a result of its location in the Transantarctic Mountains. The prevailing winds converge and deposit debris on the Cotton Glacier, warming up the surface and increasing meltwater production. During the austral summer of 2004-2005 we sampled a braided stream that flowed from mid glacier into a series of crevasses downstream. While low in dissolved organic carbon (44-47 ?M C) and nutrients the supraglacial stream on the Cotton Glacier is capable of sustaining life, with bacterial cell abundances from 2.7 - 8.2 x 104 cells ml-1, and bacterial production ranging from 58.84 - 293.18 ng C d-1. Isolates recovered from the Cotton Glacier produced a rainbow of pigment colors and were similar to those recovered from other icy systems (Cytophaga- Flavobateria-Bacteroides and ?-Proteobacteria lineages), suggesting that the occurrence of these related phylotoyes from diverse environs is due to similar survival strategies allowing them to remain active at sub- zero temperatures and survive multiple freeze-thaw events. Two isolates from the Cotton Glacier have been shown to possess ice nucleating activity. These bacteria can catalyze ice formation at -3.5C and colder temperatures and likely possess Type I ice nuclei proteins. The fluorescence and absorbance spectra of the filtered Cotton Glacier water were analyzed to characterize the dissolved organic matter (DOM). The absorbance spectra of the Cotton Glacier sample exhibited a peak around 270 nm, which disappeared over time in the dark at 4C. Analysis of excitation-emission matrices (EEMs) from the Cotton Glacier differed from typical DOM EEMs. The Cotton Glacier EEMs showed almost no fluorescence in the region of EEMs where peaks are normally present and have been attributed to the presence of humic and fulvic organic matter (Ex/Em 240/450 and 330/450). In contrast to most DOM EEMs, the Cotton Glacier EEMs were dominated by peaks in the amino-acid region (Ex/Em 240-270/300-350 nm). Thus, both the initial peak in absorbance at 270 nm and the EEM peaks in the amino-acid region suggest that the DOM present in this system is predominately proteinaceous material likely of microbial origin. This study demonstrates the presence of an active microbial assemblage in a supraglacial stream from a pristine Antarctic glacier. Recent discoveries over the past decade have shown that glacial ice contains an important record of microorganisms on our planet that theoretically could be used to assess biogeochemical processes and habitat types that occurred during past glacial and interglacial periods. This record may also contain information on microbial evolution and physiology, and provide new biotechnological innovations. Supraglacial streams provide an important example of contemporary microbial processes on the glacier surface.

Foreman, C. M.; Morris, C. E.; Cory, R. M.

2006-12-01

235

HIGH ICE, Continuation Some glacier image analysis capabilities  

E-print Network

.GLIMS.orgwww.GLIMS.org #12;Tasman glacier, New Zealand 25 km Mt. Cook Courtesy of Andreas Kaeaeb #12;Baltoro GlacierHIGH ICE, Continuation Some glacier image analysis capabilities #12;VNIR bands 321 RGB 2001, Sep. 6 RickRick WesselsWessels 12/0112/01 Glacier mapping using simple ratios of ASTER band 7 (2.25) / band 1

236

Black soot and the survival of Tibetan glaciers  

PubMed Central

We find evidence that black soot aerosols deposited on Tibetan glaciers have been a significant contributing factor to observed rapid glacier retreat. Reduced black soot emissions, in addition to reduced greenhouse gases, may be required to avoid demise of Himalayan glaciers and retain the benefits of glaciers for seasonal fresh water supplies. PMID:19996173

Xu, Baiqing; Cao, Junji; Hansen, James; Yao, Tandong; Joswia, Daniel R.; Wang, Ninglian; Wu, Guangjian; Wang, Mo; Zhao, Huabiao; Yang, Wei; Liu, Xianqin; He, Jianqiao

2009-01-01

237

Extracting a Climate Signal from 169 Glacier Records  

E-print Network

Extracting a Climate Signal from 169 Glacier Records 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

Wright, Dawn Jeannine

238

Seasonal variability of organic matter composition in an Alaskan glacier outflow: insights into glacier carbon sources  

NASA Astrophysics Data System (ADS)

Glacier ecosystems are a significant source of bioavailable, yet ancient dissolved organic carbon (DOC). Characterizing DOC in Mendenhall Glacier outflow (southeast Alaska) we document a seasonal persistence to the radiocarbon-depleted signature of DOC, highlighting ancient DOC as a ubiquitous feature of glacier outflow. We observed no systematic depletion in ? 14C-DOC with increasing discharge during the melt season that would suggest mobilization of an aged subglacial carbon store. However, DOC concentration, ? 13C-DOC, ? 14C-DOC and fluorescence signatures appear to have been influenced by runoff from vegetated hillslopes above the glacier during onset and senescence of melt. In the peak glacier melt period, the ? 14C-DOC of stream samples at the outflow (-181.7 to -355.3) was comparable to the ? 14C-DOC for snow samples from the accumulation zone (-207.2 to -390.9), suggesting that ancient DOC from the glacier surface is exported in glacier runoff. The pre-aged DOC in glacier snow and runoff is consistent with contributions from fossil fuel combustion sources similar to those documented previously in ice cores and thus provides evidence for anthropogenic perturbation of the carbon cycle. Overall, our results emphasize the need to further characterize DOC inputs to glacier ecosystems, particularly in light of predicted changes in glacier mass and runoff in the coming century.

Spencer, Robert G. M.; Vermilyea, Andrew; Fellman, Jason; Raymond, Peter; Stubbins, Aron; Scott, Durelle; Hood, Eran

2014-05-01

239

Title: Climate-glacier Relationship of Retreating Alaskan Glaciers Author: Elliott Mazur and Umesh K. Haritashya  

NASA Astrophysics Data System (ADS)

Portage, Whittier, Eklutna, as well as many other well-known "tourism glaciers" in the vicinity of Anchorage, Alaska are known to have retreated in the past 20 years. This begs the question, "what of the other lesser-known glaciers? Do they follow the same patterns and minimal glacier models?" Glaciers such as Byron, Leonard, Matanuska, Raven and Spencer may fit a minimal model. Information on Byron and Leonard is sparse, as both have become hanging glaciers. Other glaciers, such as Raven, are small enough to be deemed insignificant, yet may have information to give. Consequently our objective is to study five Alaskan glaciers and determine wide-ranging variability to changing regional climate. To do this we obtained field geo-location data and characterized glaciers based on the satellite imagery and climate reevaluation. Our result shows that glaciers are retreating and thinning irrespective of their aspects, location and altitudinal variability. Moreover, our presentation establishes the strong climate-glacier relationship and defines retreating snowline patterns over the last few decades.

Mazur, E. M.

2012-12-01

240

Quantifying global warming from the retreat of glaciers  

SciTech Connect

Records of glacier fluctuations compiled by the World Glacier Monitoring Service can be used to derive an independent estimate of global warming during the last 100 years. Records of different glaciers are made comparable by a two-step scaling procedure; one allowing for differences in glacier geometry, the other for differences in climate sensitivity. The retreat of glaciers during the last 100 years appears to be coherent over the globe. On the basis of modeling of the climate sensitivity of glaciers, the observed glacier retreat can be explained by a linear warming trend of 0.66 kelvin per century.

Oerlemans, J. (Utrecht Univ. (Netherlands))

1994-04-08

241

Combining a Distributed Melt Model and Meteorological Data of Shackleton Glacier, Canadian Rockies  

NASA Astrophysics Data System (ADS)

Runoff from the Canadian Rocky Mountains into the Upper Columbia and Kootenay basins is strongly dominated by winter snow accumulation and spring melt, and it has been suggested that future reductions in snowpack will create increased competition for water between spring and early fall (Hamlet & Lettenmaier, 1999). Although the glacierised area is substantial for affecting summer flows in these basins, there are no measurements or quantified estimates of glacier runoff contribution. In an effort to provide an estimate of glacier runoff for the region, we measured ablation over 5 years, set up weather stations and temperature sensors in Summers 2009 and 2010 and developed a melt model for Shackleton Glacier (42.5 km2), the largest outlet of the Clemenceau Icefield Group (271 km2), which is the major local ice mass feeding into the Upper Columbia basin. Two HOBO weather stations (WS) were installed on the glacier for two weeks in Summer 2010, one near the left lateral moraine on very dirty ice, and one mid-glacier on relatively clean ice. Instrumentation included pyranometers (solar radiation and albedo), and temperature, wind speed and direction, relative humidity and barometric pressure sensors. A weather station off ice provided additional temperature and precipitation data. Other data included daily ablation stake measurements, surface roughness measurements, temperature data from Tidbit loggers on and off ice, and daily manual weather observations. Yearly ablation stake measurements and summer weather observations have been made by our team since 2005. A BC River Forecast Centre automatic snow pillow station provides additional temperature and precipitation data. Using these meteorological and ablation data for parameterisation and optimisation, a distributed GIS melt model was constructed from a simple energy balance model. The model is driven by hourly direct and diffuse radiation and DEM hillshading, an albedo parameterisation based on four ice/snow zones identified from a satellite image and field measurements, constant daily values of longwave radiation as a function of percent cloud cover, and sensible heat input as a function of air temperature, katabatic wind, surface roughness and elevation. Latent heat was considered negligible. Novel aspects of the melt model include a valley temperature threshold for katabatic wind (using on and off ice temperatures and katabatic wind speed) and slope corrected area melt and radiation calculations. In an attempt to quantify energy balance effects of tributary-trunk detachment due to glacier recession related glacier fragmentation, special attention was paid to the potential influence from lateral moraines and valley walls and very dirty ice on the ablation in ice marginal regions. Observations suggest that, when katabatic wind diminishes, heat advection from an even moderately warmer lateral moraine can raise nearby glacier temperature substantially. This suggests that a combination of katabatic wind fields and proximity to lateral moraines/rock walls may be important in calculations of sensible heat contribution to surface melt in recently fragmented glacier systems.

Mueller, M.; Jiskoot, H.

2010-12-01

242

Welcome to GLACIER Tax Prep We hope you find GLACIER Tax Prep simple to use and easy to understand!  

E-print Network

Welcome to GLACIER Tax Prep We hope you find GLACIER Tax Prep simple to use and easy to understand institution has licensed GLACIER Tax Prep (which replaces CINTAX) to assist you in this process. Following available BEFORE I login to GLACIER Tax Prep? · Passport; · Visa/Immigration Status information, including

Mullins, Dyche

243

Monitoring of Grandes Jorasses hanging glacier (Aosta Valley, Italy): improving monitoring techniques for glaciers instability  

NASA Astrophysics Data System (ADS)

Grandes Jorasses serac is an unbalanced hanging glacier located on the south side of Mont Blanc Massif (Aosta Valley - Italy). It stands above Ferret Valley, a famous and most frequented touristic site both in winter and summer. Historical data and morphological evidences show that the glacier is subject to recurrent icefalls which can be dangerous especially in winter, as they can trigger catastrophic combined snow and ice avalanches. Serac dynamic was monitored in 1997-98 by prof. M Funk (ETH Zurich) by means of temperature and topographic measurement. These allowed to forecast the breakdown within a 2 days time. Thanks to a monitoring program, a new instability could be recognized in autumn 2008: a crevasse opening in the lower part of the hanging glacier. A new monitoring system was installed recently, consisting of stakes with prisms on serac surface and an automatic total station (theodolite plus distantiometer) sited on the valley floor. Monitoring is based on an empirically based power law (developed by ETH) that describes the increasing displacement rate before collapse. This monitoring system requires to measure displacement rate of the serac continuously. Although the topographic system is so far the state-of-the.art method, it implies some troubles: (i) the difficulty in placing stakes on the steep and dangerous glacier surface; (ii) potential instability of stakes themselves due to snow pressure in winter and surface ice melting in summer; (iii) impossibility to carry out measurement in case of cloudy or stormy weather, which is rather a frequent situation on Grandes Jorasses peak. Moreover, hazard and risk management require some more informations, such as the instable ice mass volume. New technologies have been applied, and are still under test, to achieve a more reliable monitoring system and a better understanding of the serac dynamics. Close-range photogrammetry techniques have been used, allowing to process helicopter-taken images and obtain quantitative data about the serac volume and crevasses widening. A low-cost GPS station has been installed in the upper part of the serac, in order to obtain long-term, continuous displacement data even in bad weather conditions. A seismograph has been installed to measure the seismic activity of the serac. The latter, as observed by ETH, significantly evolves before the seracfall; thus, the record of the seismic activity can be used to forecast the break-off. Finally, a ground-based SAR system has been tested to infer seracs displacement. Possible avalanches scenarios consequent to an icefall have been calculated by numerical simulation by the SLF Institute of Davos. In-situ measurement techniques have to be designed to resist often in the difficult environmental conditions (low temperature, frost, wind), dealing, e.g. with power supply and data transmission, and purpose-made technical solutions are often necessary. The development of these techniques will contribute to an improved understanding of the seracs dynamics and provide a more reliable monitoring tool.

Vagliasindi, Marco; Funk, Martin; Faillettaz, Jerome; Dalban, Pierre; Lucianaz, Claudio; Diotri, Fabrizio; Motta, Elena; Margreth, Stephan

2010-05-01

244

Climate Change and Glacier Retreat: Scientific Fact and Artistic Opportunity  

Microsoft Academic Search

Mountain glaciers continue to retreat rapidly over most of the globe. In North America, at Glacier National Park, Montana, recent research results from Sperry Glacier (2005-2007) indicate negative mass balances are now 3-4 times greater than in the 1950s. A geospatial model of glacier retreat in the Blackfoot-Jackson basin suggested all glaciers would be gone by 2030 but has proved

D. B. Fagre

2008-01-01

245

Glacier volume changes at Mt. Everest\\/Qomolangma 1962 - 2007  

Microsoft Academic Search

The larger glaciers at Mt. Everest are heavily covered with supra-glacial debris like many other glaciers in the Himalaya. Most glacier change studies concentrate on area change only. However, the melting of debris-covered glaciers is most recognisable through downwasting. Hence, multi-temporal DEM analysis is needed to study the reaction of these glaciers to climate change in detail. We generated a

Tobias Bolch; Tino Piezconka; Feng Chen; Shichang Kang; Manfred Buchroithner

2010-01-01

246

Sensitivity of glaciers and small ice caps to greenhouse warming  

Microsoft Academic Search

Recent field programs on glaciers have supplied information that makes simulation of glacier mass balance with meteorological models meaningful. An estimate of world-wide glacier sensitivity based on a modeling study of 12 selected glaciers situated in widely differing climatic regimes shows that for a uniform 1 K warming the area-weighted glacier mass balance will decrease by 0.40 meter per year.

J. Oerlemans; J. P. F. Fortuin

1992-01-01

247

Glaciers in Patagonia: Controversy and prospects  

NASA Astrophysics Data System (ADS)

Lately, glaciers have been subjects of unceasing controversy. Current debate about planned hydroelectric facilitiesa US$7- to $10-billion megaprojectin a pristine glacierized area of Patagonia, Chile [Romero Toledo et al., 2009; Vince, 2010], has raised anew the matter of how glaciologists and global change experts can contribute their knowledge to civic debates on important issues. There has been greater respect for science in this controversy than in some previous debates over projects that pertain to glaciers, although valid economic motivations again could trump science and drive a solution to the energy supply problem before the associated safety and environmental problems are understood. The connection between glaciers and climate changeboth anthropogenic and naturalis fundamental to glaciology and to glaciers' practical importance for water and hydropower resources, agriculture, tourism, mining, natural hazards, ecosystem conservation, and sea level [Buytaert et al., 2010; Glasser et al., 2011]. The conflict between conservation and development can be sharper in glacierized regions than almost anywhere else. Glaciers occur in spectacular natural landscapes, but they also supply prodigious exploitable meltwater.

Kargel, J. S.; Alho, P.; Buytaert, W.; Clleri, R.; Cogley, J. G.; Dussaillant, A.; Guido, Z.; Haeberli, W.; Harrison, S.; Leonard, G.; Maxwell, A.; Meier, C.; Poveda, G.; Reid, B.; Reynolds, J.; Rodrguez, C. A. Portocarrero; Romero, H.; Schneider, J.

2012-05-01

248

Interaction between glacier and glacial lake in the Bhutan, Himalaya  

NASA Astrophysics Data System (ADS)

Recession of mountain glaciers in the Himalayas has been reported in the context of global warming. Associated with the glacier retreat, supraglacial lakes have been formed on the termini of debris-covered glaciers. Although it has been said that lake-terminating glaciers flow faster than land-terminating glaciers, observational evidence was scarce. We observationally investigated the influence of the presence/absence of glacial lakes on changes in surface elevation through glacier dynamics in two debris-covered glaciers, Thorthormi Glacier (land-terminating) and Lugge Glacier (lake-terminating), in the Lunana region, the Bhutan Himalaya. We surveyed the surface elevation of debris-covered areas of the two glaciers in 2004 and 2011 by a differential GPS. Change in surface elevation of the lake-terminating Lugge Glacier was much more negative than that of the land-terminating Thorthormi Glacier. Considering almost flat slope and location at lower elevation, however, larger ice thinning rate of the Thorthormi Glacier should have been expected than the Lugge Glacier. We measured surface flow speed of the two glaciers during 2009-2010 by multitemporal orthorectified The Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) images of ALOS. Surface flow speed of the Thorthormi Glacier was faster in the upper reaches and reduced toward the downstream. In contrast, the flow speed at the Lugge Glacier measured in the same periods was greatest at the lower most part. Observed spatial distribution of surface flow speed at both glaciers are evaluated by a two-dimensional numerical flow model. The model shows that contribution of basal sliding to surface flow velocity is large in the lower part of both glaciers. Particularly in the Thorthormi Glacier, approximately 100% of surface flow velocity attribute to basal sliding. Calculated emergence velocity at the Thorthormi Glacier is larger than that at the Lugge Glacier. This result suggests that decreasing in flow velocity towards the terminus in the Thorthormi Glacier causes compressive flow and thus counterbalances surface melting, resulting in inhibition of the surface lowering. In contrast, the extensional flow of the Lugge Glacier accelerated the surface lowering. In this study we show the observational evidences, in which the glacier lake formation makes contrast the thinning rates of glaciers in the Bhutan Himalaya. If the supraglacial lake on Thorthormi Glacier expands, the surface lowering will be accelerated in the future.

Tsutaki, S.; Fujita, K.; Yamaguchi, S.; Sakai, A.; Nuimura, T.; Sugiyama, S.; Komori, J.; Takenaka, S.; Tshering, P.

2012-12-01

249

Alaska PaleoGlacier Atlas: A Geospatial Compilation of Pleistocene Glacier Extents  

NSDL National Science Digital Library

The Alaska PaleoGlacier (APG) Atlas is a recently released, web-based summary of Pleistocene glaciation across Alaska. Students can access a gallery of maps depicting the extent of glaciers during the late Wisconsin glaciation in Alaska as well as the maximum extent reached during the last 3 million years by valley glaciers, ice caps, and the northwestern Cordilleran Ice Sheet. a set of links is also provided to sites on galcial geology and glacial geospatial data.

William Manley

250

GLACIER and related R&D  

E-print Network

Liquid argon detectors, with mass up to 100 kton, are being actively studied in the context of proton decay searches, neutrino astrophysics and for the next generation of long baseline neutrino oscillation experiments to study the neutrino mass hierarchy and CP violation in the leptonic sector. The proposed Giant Liquid Argon Charge Imaging ExpeRiment (GLACIER) offers a well defined conceptual design for such a detector. In this paper we present the GLACIER design and some of the R&D activities pursued within the GLACIER.

Curioni, Alessandro

2011-01-01

251

Acceleration of West Antarctic glacier discharge  

NASA Astrophysics Data System (ADS)

The glaciers that flow from the West Antarctic Ice Sheet into the Amundsen Sea are some of the fastest on the continent. Together they account for roughly a third of the flow from the west part of the ice sheet. Over the past few decades these glaciers have only gotten faster: From 1973 to 2013 their combined rate of discharge increased 77%, report Mouginot et al. As much as half of this increase took place in a burst from 2003 to 2009, and in recent years the combined discharge of these glaciers has accounted for nearly 10% of global sea level rise.

Schultz, Colin

2014-08-01

252

Surface energy balance of Keqicar Glacier, Tianshan Mountains, China, during ablation period  

NASA Astrophysics Data System (ADS)

The meteorological data of ablation season in 2005 were recorded by two automatic weather stations on Keqicar Glacier in southwestern Tianshan Mountains in China. One is operated on the glacier near the equilibrium line with the altitude of 4265 m (site A) and another is operated on the glacier ablation area with the altitude of 3700 m (site B). These data were used to analyze the meteorological conditions and the surface energy balance (SEB) of Keqicar Glacier. The net radiation was directly measured, and the turbulent fluxes were calculated using the bulk aerodynamic approach, including stability correction. The ablation value of 0.68 m w.e derived from four ablation stakes is in close correspondence to the modeled ablation value of 0.71 m w.e calculated from the surface energy balance. During the observation period, the net radiation accounts for 81.4% of the total energy with its value of 63.3 W m-2. The rest energy source is provided by the sensible turbulent heat flux with its value of 14.4 W m-2. Energy is consumed mainly by melting and the evaporation, accounting for 69.5% and 29.7% of the total energy with their values of 54.0 W m-2 and 23.0 W m-2 respectively. The radiative energy dominates energy exchanges at the glacier-atmosphere interface, governed by the variation in net shortwave radiation. Net short-wave radiation varies significantly due to the effects of cloudiness and the high albedo caused by fallen snow. Wind speed influences the turbulent fluxes distinctively and sensible and latent flux is much bigger on July with high wind speed

Li, Jing; Liu, Shiyin; Zhang, Yong; Han, Haidong

2010-05-01

253

Modeled Climate-Induced Glacier Change in Glacier National Park, 1850--2100  

NSDL National Science Digital Library

This peer-reviewed article from BioScience journal is about the glacier change in Glacier National park. The glaciers in the Blackfoot--Jackson Glacier Basin of Glacier National Park, Montana, decreased in area from 21.6 square kilometers (km2) in 1850 to 7.4 km2 in 1979. Over this same period global temperatures increased by 0.45 degrees C (+/- 0.15 degrees C). We analyzed the climatic causes and ecological consequences of glacier retreat by creating spatially explicit models of the creation and ablation of glaciers and of the response of vegetation to climate change. We determined the melt rate and spatial distribution of glaciers under two possible future climate scenarios, one based on carbon dioxide--induced global warming and the other on a linear temperature extrapolation. Under the former scenario, all glaciers in the basin will disappear by the year 2030, despite predicted increases in precipitation; under the latter, melting is slower. Using a second model, we analyzed vegetation responses to variations in soil moisture and increasing temperature in a complex alpine landscape and predicted where plant communities are likely to be located as conditions change.

MYRNA H. P. HALL and DANIEL B. FAGRE (; )

2002-02-01

254

Biogeochemistry of glacier and rock glacier outflow in the western United States  

NASA Astrophysics Data System (ADS)

Glaciers are melting at unprecedented rates worldwide, releasing bioavailable minerals and nutrients and altering downstream biogeochemistry. Though much research has focused on the recession of ice-glaciers in alpine environments, far less is known about the melt dynamics and biogeochemistry of rock glaciers. Rock glaciers, which are mixtures of ice and rocks that flow like a glacier, are far more abundant in mountainous regions of the western United States than ice glaciers. Little is known about their influence on downstream hydrology and water quality. We report here preliminary results of a west-wide survey of the influence of glaciers and rock glaciers on headwater properties. Measurements of specific conductance, nitrate (NO3-), ammonium (NH4+), dissolved silica, and dissolved organic matter were compared between glaciers, rock glaciers, and snow-fed reference streams from three basins in the Colorado Front Range. Samples were collected from ice, where possible, and downstream at 500m intervals from the first flowing water to tree line. UV and fluorescence data were analyzed using excitation emission matrices (EEMs) and PARAFAC modeling. High concentrations of NH4+ were only found in ice and the most upstream locations; NH4+ was below detection at all lower elevation sites, whereas NO3- concentrations were low in the headwaters and higher downstream. The fluorescence spectrum of DOC from both ice and the highest elevations had a strong autochthonous (microbial or algal) signal that was replaced by a more allochtonous, terrestrially-derived DOC as it approached tree line. Rock glacier stream chemistry was intermediate between glacier-fed streams and strictly snow fed drainages. DOC levels for ice glaciers ranged 2-3mg/L with increasing values downstream, while rock glaciers ranged from 1-2.5 mg/L with attenuation downstream. Snowfed only streams had DOC values at detection <0.5mg/L, with the exception at Lake Husted outflow, with an upland wetland, unlike the other snow-fed streams sampled. SUVA 254, an index of aromaticity of the dissolved organic matter, was lower in streams fed by rock glaciers than ice glaciers and snow fed streams. This is potentially indicative of microbial processing in streams fed by rock glaciers. Fluorescence index was highest for ice glaciers (1.44), lowest for snow-fed streams (1.33), and a medial value for rock glaciers (1.42). Freshness index, which indicates the proportion of recently produced dissolved organic matter, was highest for ice glacier streams, and lowest for rock glacier streams, and showed the most variability between sites with snow-fed streams. More research is planned, but rock glaciers appear more similar to ice glaciers than snow-fed streams in their influence on alpine stream chemistry on biology, suggesting a trajectory of change of the mountains as ice features waste away.

Fegel, T. S.; Baron, J.; Hall, E.; Boot, C. M.

2013-12-01

255

A Revised Glacier Inventory of Bhaga Basin Himachal Pradesh, India : Current Status and Recent Glacier Variations  

NASA Astrophysics Data System (ADS)

Himalayan glaciers show large uncertainty regarding their present and future state due to their sensitive reaction towards change in climatic condition. Himalayan glaciers are unique as they are located in tropical, high altitude regions, predominantly valley type and many are covered with debris. The great northern plains of India sustain on the perennial melt of glaciers meeting the water requirements of agriculture, industries, domestic sector even in the months of summer when large tracts of the country go dry. Therefore, it is important to monitor and assess the state of snow and glaciers and to know the sustainability of glaciers in view of changing global scenarios of climate and water security of the nation. Any information pertaining to Himalayan glaciers is normally difficult to be obtained by conventional means due to its harsh weather and rugged terrains. Due to the ecological diversity and geographical vividness, major part of the Indian Himalaya is largely un-investigated. Considering the fact that Himalayan glaciers are situated in a harsh environment, conventional techniques of their study is challenging and difficult both in terms of logistics and finances whereas the satellite remote sensing offers a potential mode for monitoring glaciers in long term. In order to gain an updated overview of the present state of the glacier cover and its changes since the previous inventories, an attempt has been made to generate a new remotesensing- derived glacier inventory on 1:50,000 scale for Bhaga basin (N3228'19.7'' - N330'9.9'' ; E7656'16.3'' - E7725'23.7'' ) Western Himalaya covering an area of 1695.63 km2. having 231 glaciers and occupying glacierized area of 385.17 3.71 km2. ranging from 0.03 km2. to 29.28 km2. Glacier inventory has been carried out using high resolution IRS P6 LISS III data of 2011, ASTER DEM and other ancillary data. Specific measurements of mapped glacier features are the inputs for generating the glacier inventory data sheet with 37 parameters as per the UNESCO/TTS format, 11 additional parameters associated with the de-glaciated valley as per the suggestions of Space Application Center Ahmadabad and 9 newly introduced parameters of present study. The data sheet provides glacier wise details for each glacier on the significant glacier parameters like morphology, dimensions, orientation, elevation, etc. for both the active glacier component as well as the associated de-glaciated valley features. Assessment of recent variation in the glacierized area between 2001 and 2011. Results indicate that 231 glaciers covering an area of 391.56 3.76 km2. in 2001 has been reduced to 385.17 3.71 km2. in 2011; a loss of 1.63 1.0% in glacierized area within a period of 10 years. The present paper brings out the methodology adopted and salient results of the glacier inventory carried out which will help to enrich the existing database required for water resources assessment of the country and also meet the requirements of various researches working on climate change related studies.

Birajdar, F.; Venkataraman, G.; Bahuguna, I.; Samant, H.

2014-11-01

256

Distinct patterns of seasonal Greenland glacier velocity  

NASA Astrophysics Data System (ADS)

Predicting Greenland Ice Sheet mass loss due to ice dynamics requires a complete understanding of spatiotemporal velocity fluctuations and related control mechanisms. We present a 5 year record of seasonal velocity measurements for 55 marine-terminating glaciers distributed around the ice sheet margin, along with ice-front position and runoff data sets for each glacier. Among glaciers with substantial speed variations, we find three distinct seasonal velocity patterns. One pattern indicates relatively high glacier sensitivity to ice-front position. The other two patterns are more prevalent and appear to be meltwater controlled. These patterns reveal differences in which some subglacial systems likely transition seasonally from inefficient, distributed hydrologic networks to efficient, channelized drainage, while others do not. The difference may be determined by meltwater availability, which in some regions may be influenced by perennial firn aquifers. Our results highlight the need to understand subglacial meltwater availability on an ice sheet-wide scale to predict future dynamic changes.

Moon, Twila; Joughin, Ian; Smith, Ben; Broeke, Michiel R.; Berg, Willem Jan; Nol, Brice; Usher, Mika

2014-10-01

257

On the Formation of Cirques by Glaciers  

E-print Network

Range, New Zealand: Earth Surface Processes and Landforms,Range, New Zealand Earth Surface Processes and LandformsNew Zealand Location Table 3.1. Cirque glacier erosion rates from the literature. landform

Sanders, John Webb

2011-01-01

258

Icebergs and Glaciers - Issue 15, August 2009  

NSDL National Science Digital Library

This issue of the free online magazine, Beyond Penguins and Polar Bears, contains content knowledge and instructional resources about icebergs and glaciers and the scientific principles of density and buoyancy.

The Ohio State University

259

Common Misconceptions about Icebergs and Glaciers  

NSDL National Science Digital Library

This article describes some common misconceptions that elementary students may have about icebergs and glaciers (including density and buoyancy). It also includes suggestions for formative assessment and teaching for conceptual change.

Jessica Fries-Gaither

260

Underwater acoustic signatures of glacier calving  

NASA Astrophysics Data System (ADS)

Climate-driven ice-water interactions in the contact zone between marine-terminating glaciers and the ocean surface show a dynamic and complex nature. Tidewater glaciers lose volume through the poorly understood process of calving. A detailed description of the mechanisms controlling the course of calving is essential for the reliable estimation and prediction of mass loss from glaciers. Here we present the potential of hydroacoustic methods to investigate different modes of ice detachments. High-frequency underwater ambient noise recordings are combined with synchronized, high-resolution, time-lapse photography of the Hans Glacier cliff in Hornsund Fjord, Spitsbergen, to identify three types of calving events: typical subaerial, sliding subaerial, and submarine. A quantitative analysis of the data reveals a robust correlation between ice impact energy and acoustic emission at frequencies below 200 Hz for subaerial calving. We suggest that relatively inexpensive acoustic methods can be successfully used to provide quantitative descriptions of the various calving types.

Glowacki, O.; Deane, G. B.; Moskalik, M.; Blondel, Ph.; Tegowski, J.; Blaszczyk, M.

2015-02-01

261

Malaspina Glacier, Alaska, Perspective with Landsat Overlay  

NASA Technical Reports Server (NTRS)

Malaspina Glacier in southeastern Alaska is considered the classic example of a piedmont glacier. Piedmont glaciers occur where valley glaciers exit a mountain range onto broad lowlands, are no longer laterally confined, and spread to become wide lobes. Malaspina Glacier is actually a compound glacier, formed by the merger of several valley glaciers, the most prominent of which seen here are Agassiz Glacier (left) and Seward Glacier (right). In total, Malaspina Glacier is up to 65 kilometers (40 miles) wide and extends up to 45 kilometers (28 miles) from the mountain front nearly to the sea.

This perspective view was created from a Landsat satellite image and an elevation model generated by the Shuttle Radar Topography Mission (SRTM). Landsat views both visible and infrared light, which have been combined here into a color composite that generally shows glacial ice in light blue, snow in white, vegetation in green, bare rock in grays and tans, and the ocean (foreground) in dark blue. The back (northern) edge of the data set forms a false horizon that meets a false sky.

Glaciers erode rocks, carry them down slope, and deposit them at the edge of the melting ice, typically in elongated piles called moraines. The moraine patterns at Malaspina Glacier are quite spectacular in that they have huge contortions that result from the glacier crinkling as it gets pushed from behind by the faster-moving valley glaciers.

Glaciers are sensitive indicators of climatic change. They can grow and thicken with increasing snowfall and/or decreased melting. Conversely, they can retreat and thin if snowfall decreases and/or atmospheric temperatures rise and cause increased melting. Landsat imaging has been an excellent tool for mapping the changing geographic extent of glaciers since 1972. The elevation measurements taken by SRTM in February 2000 now provide a near-global baseline against which future non-polar region glacial thinning or thickening can be assessed.

Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on February 11, 2000. The mission used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar that flew twice on the Space Shuttle Endeavour in 1994. The Shuttle Radar Topography Mission was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC. Size: 55 kilometers wide x 55 kilometers distance (34 x 34 miles) Location: 60 deg N latitude, 140 deg W longitude Orientation: View North, 2X vertical exaggeration Image Data: Landsat Thematic Mapper false-color image Original Data Resolution: SRTM 1 arcsecond (30 meters or 98 feet), Landsat 30 meters (98 feet) Date Acquired: February 2000 (SRTM), 31 August 2000 (Landsat)

2003-01-01

262

Hidden Lake in Glacier National Park, Montana  

USGS Multimedia Gallery

Hidden Lake in Glacier National Park, Montana, USA, a high mountain lake in an alpine setting. This lake is kept full of water mainly from precipitation runoff from the surrounding hills and, in the spring, from snowmelt....

263

Interferometric and polarimetric SAR for glacier investigation in west China  

NASA Astrophysics Data System (ADS)

The glacier is an important factor in climatologic and hydrological investigations, especially in western China. Remote sensing plays an important role for glacier inventorying and monitoring work. SAR systems have an ability to observe the earth's surface, independent of cloud conditions. Particularly, the interferometry and polarization SAR provide a useful tool for glacier investigation, such as extraction of glacial border, measurement of glacier movement and so on. In this paper, we demonstrate the methods and results for the glacier identification integrated intensity of backscattering from Envisat/ASAR images, coherence coefficients of repeat pass interferometry from ASAR and PALSAR, and full polarimetric SAR from PALSAR0 The movements of several types of glaciers were retrievaled using the SAR interferometry, such as continental glacier, sub-continental glacier and maritime glacier.

Li, Zhen; Zhou, Jianmin; Tian, Bangsen; Huang, Lei

2009-09-01

264

Interferometric and polarimetric SAR for glacier investigation in west China  

NASA Astrophysics Data System (ADS)

The glacier is an important factor in climatologic and hydrological investigations, especially in western China. Remote sensing plays an important role for glacier inventorying and monitoring work. SAR systems have an ability to observe the earth's surface, independent of cloud conditions. Particularly, the interferometry and polarization SAR provide a useful tool for glacier investigation, such as extraction of glacial border, measurement of glacier movement and so on. In this paper, we demonstrate the methods and results for the glacier identification integrated intensity of backscattering from Envisat/ASAR images, coherence coefficients of repeat pass interferometry from ASAR and PALSAR, and full polarimetric SAR from PALSAR0 The movements of several types of glaciers were retrievaled using the SAR interferometry, such as continental glacier, sub-continental glacier and maritime glacier.

Li, Zhen; Zhou, Jianmin; Tian, Bangsen; Huang, Lei

2010-11-01

265

Towards a complete World Glacier Inventory  

NASA Astrophysics Data System (ADS)

The need for an inventory of the world's glaciers evolved during the International Hydrological Decade (1965-74). As a result, guidelines were established in the mid 1970s to compile a worldwide detailed inventory of existing perennial snow and ice masses. Following these international guidelines, several countries started compiling national glacier inventories based primarily on aerial photographs and maps. In the 1980s, the World Glacier Inventory (WGI) database was launched together with a status report about global and regional glacierised surface areas for the second half of the 20th century. These estimates were based on the detailed inventory data together with preliminary estimates of the remaining glacierised regions derived from early satellite imagery. In the late 1990s, the Global Land Ice Measurements from Space (GLIMS) database was initiated to continue the inventory task with space-borne sensors. In the WGI, glaciers are represented by geographical point coordinates. The GLIMS database includes digital outlines. Both include exact time stamps and tabular information on glacier classifications, length, area, orientation, and altitude range. Both are regularly updated with newly available data: the WGI stores point information for the second half of the 20th century whereas the GLIMS includes digital outlines for the 21st century. Since these detailed glacier inventories are not (yet) globally complete, there have been several efforts towards preliminary estimates of the overall global glacier coverage. A first, well elaborated one was included in the original status report of the WGI, published in 1989, and was refined in 2005 with information from other sources by Dyurgerov and Meier. Other studies used the detailed WGI, or an extended format by Cogley, for regional or global up-scaling of glacier extents. In 2003, Cogley published a global map of percentage glacier coverage per 1x1 grid box (GGHydro) that is widely used for modeling at global scale. A first globally and almost complete map with (generalized) digital outlines of all ice covered regions (incl. Greenland but excluding Antarctica) was derived from ESRI's Digital Chart of the World (DCW) and other sources by Raup and colleagues in 2000. Most recently, Arendt and colleagues produced the Randolph dataset which combines available outlines from the GLIMS, DCW, and WGI datasets as well as from many other (often unpublished) sources by using the highest quality version in each region. However, while having the advantage of being almost complete, these global estimates lack time stamps and attributes for individual glaciers. The present work provides a brief review of the various efforts, its methodological differences, and findings towards the completion of a World Glacier Inventory.

Zemp, Michael

2013-04-01

266

Glacier area and length changes in Norway from repeat inventories  

NASA Astrophysics Data System (ADS)

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.

Winsvold, S. H.; Andreassen, L. M.; Kienholz, C.

2014-10-01

267

International Symposium on Fast Glacier Flow  

NASA Technical Reports Server (NTRS)

Cryospheric Sciences Program "International Symposium on Fast Glacier Flow" (PI, C. Lingle) provided partial support for publication of Annals of Glaciology 36 by the International Glaciological Society. Annals of Glaciology is a peer-reviewed journal. Annals 36, which was published in 2003, contains 39 peer-reviewed and edited papers from the International Symposium on Fast Glacier Flow, which was held in Yakutat, Alaska, 10-14 June 2002.

Lingle, Craig S.

1990-01-01

268

Regional Observations of Alaska Glacier Dynamics  

NASA Astrophysics Data System (ADS)

Alaska glaciers contribute more to sea level rise than any other glacierized mountain region in the world. Alaska is loosing ~84 Gt of ice annually, which accounts for ~0.23 mm/yr of SLR (Luthcke et al., 2008). Complex glacier flow dynamics, frequently related to tidewater environments, is the primary cause of such rapid mass loss (Larsen et al., 2007). Indirect observations indicate these complex flow dynamics occur on many glaciers throughout Alaska, but no comprehensive velocity measurements exist. We are working to measure glacier surface velocities throughout Alaska using synthetic aperture radar (SAR) offset tracking. This work focuses on the Seward/Malaspina, Bering, Columbia, Kaskawulsh, and Hubbard Glaciers and uses a MODIS land surface temperature "melt-day" product (Hall et al., 2006, 2008) to identify potential links between velocity variability and summertime temperature fluctuations. Hall, D., R. Williams Jr., K. Casey, N. DiGirolamo, and Z. Wan (2006), Satellite-derived, melt-season surface temperature of the Greenland Ice Sheet (2000-2005) and its relationship to mass balance, Geophysical Research Letters, 33(11). Hall, D., J. Box, K. Casey, S. Hook, C. Shuman, and K. Steffen (2008), Comparison of satellite-derived and in-situ observations of ice and snow surface temperatures over Greenland, Remote Sensing of Environment, 112(10), 3739-3749. Larsen, C. F., R. J. Motyka, A. A. Arendt, K. A. Echelmeyer, and P. E. Geissler (2007), Glacier changes in southeast Alaska and northwest British Columbia and contribution to sea level rise, J. Geophys. Res. Luthcke, S., A. Arendt, D. Rowlands, J. McCarthy, and C. Larsen (2008), Recent glacier mass changes in the Gulf of Alaska region from GRACE mascon solutions, Journal of Glaciology, 54(188), 767-777.

Burgess, E. W.; Forster, R. R.; Hall, D. K.

2010-12-01

269

Impacts of Change in Glacier Ice  

NSDL National Science Digital Library

This is a five-activity module that explores the evidence for and impacts of melting glacial ice, with resources from major institutions and scientists who study glaciers -- primarily in Arctic areas. The suite of activities includes both glaciers and melting ice, as well as the impact of melt water downstream. Each activity follows the 5E model of Engagement, Exploration, Explanation, Elaboration, and Evaluation.

Alaska Sea Grant

270

Fuzzy Cognitive Maps for Glacier Hazards Assessment: Application to Predicting the Potential for Glacier Lake Outbursts  

NASA Astrophysics Data System (ADS)

Glaciers and ice sheets are among the largest unstable parts of the solid Earth. Generally, glaciers are devoid of resources (other than water), are dangerous, are unstable and no infrastructure is normally built directly on their surfaces. Areas down valley from large alpine glaciers are also commonly unstable due to landslide potential of moraines, debris flows, snow avalanches, outburst floods from glacier lakes, and other dynamical alpine processes; yet there exists much development and human occupation of some disaster-prone areas. Satellite remote sensing can be extremely effective in providing cost-effective and time- critical information. Space-based imagery can be used to monitor glacier outlines and their lakes, including processes such as iceberg calving and debris accumulation, as well as changing thicknesses and flow speeds. Such images can also be used to make preliminary identifications of specific hazardous spots and allows preliminary assessment of possible modes of future disaster occurrence. Autonomous assessment of glacier conditions and their potential for hazards would present a major advance and permit systematized analysis of more data than humans can assess. This technical leap will require the design and implementation of Artificial Intelligence (AI) algorithms specifically designed to mimic glacier experts reasoning. Here, we introduce the theory of Fuzzy Cognitive Maps (FCM) as an AI tool for predicting and assessing natural hazards in alpine glacier environments. FCM techniques are employed to represent expert knowledge of glaciers physical processes. A cognitive model embedded in a fuzzy logic framework is constructed via the synergistic interaction between glaciologists and AI experts. To verify the effectiveness of the proposed AI methodology as applied to predicting hazards in glacier environments, we designed and implemented a FCM that addresses the challenging problem of autonomously assessing the Glacier Lake Outburst Flow Potential and Impound Water Upstream Flow Potential. The FCM is constructed using what is currently our understanding of how glacier lake outbursts occur, whereas the causal connection between concepts is defined to capture the expertise of glacier scientists. The proposed graph contains 27 nodes and a network of connections that represent the causal link between concepts. To test the developed FCM, we defined three scenarios representing glacier lake environmental conditions that either occurred or that are likely to occur in such highly dynamic environments. For each case, the FCM has been initialized using observables extracted from hypothesized remote sensing imagery. The map, which converges to a fixed point for all of the test scenarios within 15 iterations, shows reasoning consistent with that of glacier experts. The FCM-based cognitive approach has the potential to be the AI core of real-time operational hazards assessment and detection systems.

Furfaro, R.; Kargel, J. S.; Fink, W.; Bishop, M. P.

2010-12-01

271

Glacier, glacier lake and permafrost distribution in the Brahmaputra river basin  

NASA Astrophysics Data System (ADS)

Glacier distribution, glacier changes, glacier lakes and their changes, and mountain permafrost occurrence are investigated and compared to climate scenarios in order to assess the influence of melting glaciers and degrading permafrost on the long-term runoff of the Upper Brahmaputra River. In this contribution we derive glacier inventories for three test areas in the Upper Brahmaputra River Basin based on semi-automatic classification of Landsat data of 2000 and supplementary ASTER data. The resulting glacier outlines are intersected with the glacier outlines of the Chinese Glacier Inventory from about the 1970s-1980s and compared to selected Corona satellite data from the 1960s. In total, an area loss of about 18% was observed over the period investigated. We estimate the according ice volume loss to be on the order of 20%. Using the Chinese Glacier Inventory and our inventory results we upscale the above glacier change to the entire Upper Brahmaputra River Basin. Glacier lakes are mapped for the boundary region between Bhutan and Tibet using 1990 and 2000 Landsat imagery. Changes in lake area are compared to the observed glacier changes. The permafrost distribution in the study region is estimated using regionally adapted versions of two empirical models, both originally developed to estimate the permafrost distribution on a regional scale in the Swiss Alps. One model (PERMAKART) applies a topo-climatic key, based on the relation between altitude above sea level, aspect, and permafrost probability. The second model (PERMAMAP) is based on a linear spatial relation between the bottom temperature of the winter snow cover (BTS), the mean annual air temperature (MAAT) and the potential direct solar radiation. Adaptation of the models is done through the inclusion of ground based meteorological data and validated using distribution patterns of rock glaciers. The latter are mapped from high resolution satellite data such as CORONA and Quickbird imagery. Both, the observed glacier changes and the modelled permafrost distribution are compared to climate simulations in order to estimate the recent and near-future climate change impact on the glaciers and mountain permafrost in the Upper Brahmaputra River basin.

Kb, A.; Frauenfelder, R.; Hoelzle, M.; Sossna, I.; Avian, M.

2009-04-01

272

Using airborne LiDAR and USGS DEM data for assessing rock glaciers and glaciers  

NASA Astrophysics Data System (ADS)

Varying topographic and geologic conditions affect the location of rock glaciers. Despite being found worldwide, rock glaciers are often confused with glacier counterparts or other periglacial landforms. Light detection and ranging (LiDAR) data, because of its accuracy and resolution, may help the assessment of topographic variables needed to form rock glaciers or help reveal unique characteristics to enhance regional, automatic mapping. The objectives of this paper are to compare the elevation, slope, aspect, hillshade, and curvature for 1 m LiDAR and 10 m US Geological Survey (USGS) Digital Elevation Models (DEMs) from the Andrews and Taylor Glaciers with the Taylor Rock Glacier in Colorado. The utility of these data sources will be assessed for landform discrimination and to evaluate the uncertainty between the DEMs. According to the LiDAR data, the Taylor Rock Glacier exists at a lower elevation and has a gentler slope compared to the glaciers. Each landform has steep areas from which snow and debris are delivered. The Andrews Glacier has the most northern aspect, which helps maintain it through snow accumulation and reduced insolation. Glaciers exhibit a concave mean curvature, whereas the Taylor Rock Glacier has a convex mean curvature. The fine resolution of the LiDAR data clearly identifies some distinct characteristics. On the Taylor Rock Glacier, ridges, furrows, and a pronounced front slope were easily identifiable on the LiDAR DEM, whereas crevasses, the boundary between snow and debris covered surfaces, and a lateral moraine were detectable near the Andrews Glacier. The accuracy assessment revealed that at a common 10 m resolution, the USGS DEM estimated a maximum elevation about 150 m greater compared to the LiDAR data in areas of rugged topography surrounding the landforms. A comparison of root mean squared errors (RMSE) between the LiDAR and USGS DEMs showed that the Taylor Rock Glacier has the lowest RMSE for the elevation and the curvature variables. As a result, readily available USGS DEMs may better for analysis to characterize the topographic setting of landforms at the regional scale. At the fine scale, however, the micro-topography of rock glaciers is illuminated much more clearly on the LiDAR data, making it an ideal, yet costly source, for feature extraction.

Janke, Jason R.

2013-08-01

273

Linking glacier annual mass balance and glacier albedo retrieved from MODIS data  

NASA Astrophysics Data System (ADS)

Albedo is one of the variables controlling the mass balance of temperate glaciers. Multispectral imagers, such as MODerate Imaging Spectroradiometer (MODIS) on board the TERRA and AQUA satellites, provide a means to monitor glacier surface albedo. In this study, different methods to retrieve broadband glacier surface albedo from MODIS data are compared. The effect of multiple reflections due to the rugged topography and of the anisotropic reflection of snow and ice are particularly investigated. The methods are tested on the Saint Sorlin Glacier (Grandes Rousses area, French Alps). The accuracy of the retrieved albedo is estimated using both field measurements, at two automatic weather stations located on the glacier, and albedo values derived from terrestrial photographs. For summers 2008 and 2009, the Root Mean Square Deviation (RMSD) between field measurements and the broadband albedo retrieved from MODIS data at 250 m spatial resolution was found to be 0.052 or about 10% relative error. The RMSD estimated for the MOD10 daily albedo product is about three times higher. One decade (2000-2009) of MODIS data were then processed to create a time series of albedo maps of Saint Sorlin Glacier during the ablation season. The annual mass balance of Saint Sorlin Glacier was compared with the minimum albedo value (average over the whole glacier surface) observed with MODIS during the ablation season. A strong linear correlation exists between the two variables. Furthermore, the date when the average albedo of the whole glacier reaches a minimum closely corresponds to the period when the snowline is located at its highest elevation, thus when the snowline is a good indicator of the glacier equilibrium line. This indicates that this strong correlation results from the fact that the minimal average albedo values of the glacier contains a considerable information regarding the relative share of areal surfaces between the ablation zone (i.e. ice with generally low albedo values) and the accumulation zone (i.e. snow with a relatively high albedo). As a consequence, the monitoring of the glacier surface albedo using MODIS data can provide a useful means to evaluate the inter-annual variability of the glacier mass balance. Finally, the albedo in the ablation area of Saint Sorlin Glacier does not exhibit any decreasing trend over the study period, contrasting with the results obtained on Morteratsch Glacier in the Swiss Alps.

Dumont, M.; Gardelle, J.; Sirguey, P.; Guillot, A.; Six, D.; Rabatel, A.; Arnaud, Y.

2012-07-01

274

Linking glacier annual mass balance and glacier albedo retrieved from MODIS data  

NASA Astrophysics Data System (ADS)

Albedo is one of the variables controlling the mass balance of temperate glaciers. Multispectral imagers, such as MODerate Imaging Spectroradiometer (MODIS) on board the TERRA and AQUA satellites, provide a means to monitor glacier surface albedo. In this study, different methods to retrieve broadband glacier surface albedo from MODIS data are compared. The effect of multiple reflections due to the rugged topography and of the anisotropic reflection of snow and ice are particularly investigated. The methods are tested on the Saint Sorlin Glacier (Grandes Rousses area, French Alps). The accuracy of the retrieved albedo is estimated using both field measurements, at two automatic weather stations located on the glacier, and albedo values derived from terrestrial photographs. For summers 2008 and 2009, the root mean square deviation (RMSD) between field measurements and the broadband albedo retrieved from MODIS data at 250 m spatial resolution was found to be 0.052 or about 10% relative error. The RMSD estimated for the MOD10 daily albedo product is about three times higher. One decade (2000-2009) of MODIS data were then processed to create a time series of albedo maps of Saint Sorlin Glacier during the ablation season. The annual mass balance of Saint Sorlin Glacier was compared with the minimum albedo value (average over the whole glacier surface) observed with MODIS during the ablation season. A strong linear correlation exists between the two variables. Furthermore, the date when the average albedo of the whole glacier reaches a minimum closely corresponds to the period when the snow line is located at its highest elevation, thus when the snow line is a good indicator of the glacier equilibrium line. This indicates that this strong correlation results from the fact that the minimal average albedo values of the glacier contains considerable information regarding the relative share of areal surfaces between the ablation zone (i.e. ice with generally low albedo values) and the accumulation zone (i.e. snow with a relatively high albedo). As a consequence, the monitoring of the glacier surface albedo using MODIS data can provide a useful means to evaluate the interannual variability of the glacier mass balance. Finally, the albedo in the ablation area of Saint Sorlin Glacier does not exhibit any decreasing trend over the study period, contrasting with the results obtained on Morteratsch Glacier in the Swiss Alps.

Dumont, M.; Gardelle, J.; Sirguey, P.; Guillot, A.; Six, D.; Rabatel, A.; Arnaud, Y.

2012-12-01

275

Linking glacier annual mass balance and glacier albedo retrieved from MODIS data  

NASA Astrophysics Data System (ADS)

Spectroradiometer (MODIS) on board the TERRA and AQUA satellites, provide a means to monitor glacier surface albedo. In this study, different methods to retrieve broadband glacier surface albedo from MODIS data are compared. The effect of multiple reflections due to the rugged topography and of the anisotropic reflection of snow and ice are particularly investigated. The methods are tested on the Saint Sorlin Glacier (Grandes Rousses area, French Alps). The accuracy of the retrieved albedo is estimated using both field measurements, at two automatic weather stations located on the glacier, and albedo values derived from terrestrial photographs. For summers 2008 and 2009, the Root Mean Square Deviation (RMSD) between field measurements and the broadband albedo retrieved from MODIS data at 250m spatial resolution was found to be 0.052 or about 10% relative error. The RMSD estimated for the MOD10 daily albedo product is about three times higher. One decade (2000-2009) of MODIS data were then processed to create a time series of albedo maps of four glaciers in the French Alps including Saint Sorlin Glacier during the ablation season. The annual mass balance of each glacier was compared with the minimum albedo value (average over the whole glacier surface) observed with MODIS during the ablation season. A strong linear correlation exists between the two variables. Furthermore, the date when the average albedo of the whole glacier reaches a minimum closely corresponds to the period when the snowline is located at its highest elevation, thus when the snowline is a good indicator of the glacier equilibrium line. This indicates that this strong correlation results from the fact that the minimal average albedo values of the glacier contains a considerable information regarding the relative share of areal surfaces between the ablation zone (i.e. ice with generally low albedo values) and the accumulation zone (i.e. snow with a relatively high albedo). As a consequence, the monitoring of the glacier surface albedo using MODIS data can provide a useful means to evaluate the inter-annual variability of the glacier mass balance. Finally, the albedo in the ablation area of Saint Sorlin Glacier does not exhibit any decreasing trend over the study period, contrasting with the results obtained on Morteratsch Glacier in the Swiss Alps.

Dumont, M.; Gardelle, J.; Sirguey, P. J.; Guillot, A.; Dcaux, L.; Rabatel, A.; Six, D.; Arnaud, Y.

2012-12-01

276

The GLIMS geospatial glacier database: A new tool for studying glacier change  

NASA Astrophysics Data System (ADS)

The Global Land Ice Measurement from Space (GLIMS) project is a cooperative effort of over sixty institutions world-wide with the goal of inventorying a majority of the world's estimated 160 000 glaciers. Each institution (called a Regional Center, or RC) oversees the analysis of satellite imagery for a particular region containing glacier ice. Data received by the GLIMS team at the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado are ingested into a spatially-enabled database (PostGIS) and made available via a website featuring an interactive map, and a Web-Mapping Service (WMS). The WMS, an Open Geospatial Consortium (OGC)-compliant web interface, makes GLIMS glacier data available to other data servers. The GLIMS Glacier Database is accessible on the World Wide Web at " http://nsidc.org/glims/". There, users can browse custom maps, display various data layers, query information within the GLIMS database, and download query results in different GIS-compatible formats. Map layers include glacier outlines, footprints of ASTER satellite optical images acquired over glaciers, and Regional Center information. The glacier and ASTER footprint layers may be queried for scalar attribute data, such as analyst name and date of contribution for glacier data, and acquisition time and browse imagery for the ASTER footprint layer. We present an example analysis of change in Cordillera Blanca glaciers, as determined by comparing data in the GLIMS Glacier Database to historical data. Results show marked changes in that system over the last 30 years, but also point out the need for establishing clear protocols for glacier monitoring from remote-sensing data.

Raup, Bruce; Racoviteanu, Adina; Khalsa, Siri Jodha Singh; Helm, Christopher; Armstrong, Richard; Arnaud, Yves

2007-03-01

277

The slow advance of a calving glacier: Hubbard Glacier, Alaska, U.S.A  

USGS Publications Warehouse

Hubbard Glacier is the largest tidewater glacier in North America. In contrast to most glaciers in Alaska and northwestern Canada, Hubbard Glacier thickened and advanced during the 20th century. This atypical behavior is an important example of how insensitive to climate a glacier can become during parts of the calving glacier cycle. As this glacier continues to advance, it will close the seaward entrance to 50 km long Russell Fjord and create a glacier-dammed, brackish-water lake. This paper describes measured changes in ice thickness, ice speed, terminus advance and fjord bathymetry of Hubbard Glacier, as determined from airborne laser altimetry, aerial photogrammetry, satellite imagery and bathymetric measurements. The data show that the lower regions of the glacier have thickened by as much as 83 m in the last 41 years, while the entire glacier increased in volume by 14.1 km3. Ice speeds are generally decreasing near the calving face from a high of 16.5 m d-1 in 1948 to 11.5 m d-1 in 2001. The calving terminus advanced at an average rate of about 16 m a-1 between 1895 and 1948 and accelerated to 32 m a-1 since 1948. However, since 1986, the advance of the part of the terminus in Disenchantment Bay has slowed to 28 m a-1. Bathymetric data from the lee slope of the submarine terminal moraine show that between 1978 and 1999 the moraine advanced at an average rate of 32 m a-1, which is the same as that of the calving face.

Trabant, D.C.; Krimmel, R.M.; Echelmeyer, K.A.; Zirnheld, S.L.; Elsberg, D.H.

2003-01-01

278

Diverse calving patterns linked to glacier geometry  

NASA Astrophysics Data System (ADS)

Iceberg calving has been implicated in the retreat and acceleration of glaciers and ice shelves along the margins of the Greenland and Antarctic ice sheets. Accurate projections of sea-level rise therefore require an understanding of how and why calving occurs. Unfortunately, calving is a complex process and previous models of the phenomenon have not reproduced the diverse patterns of iceberg calving observed in nature. Here we present a numerical model that simulates the disparate calving regimes observed, including the detachment of large tabular bergs from floating ice tongues, the disintegration of ice shelves and the capsizing of smaller bergs from grounded glaciers that terminate in deep water. Our model treats glacier ice as a granular material made of interacting boulders of ice that are bonded together. Simulations suggest that different calving regimes are controlled by glacier geometry, which controls the stress state within the glacier. We also find that calving is a two-stage process that requires both ice fracture and transport of detached icebergs away from the calving front. We suggest that, as a result, rapid iceberg discharge is possible in regions where highly crevassed glaciers are grounded deep beneath sea level, indicating portions of Greenland and Antarctica that may be vulnerable to rapid ice loss through catastrophic disintegration.

Bassis, J. N.; Jacobs, S.

2013-10-01

279

Rheology of rock glaciers: a preliminary assessment  

SciTech Connect

Movement of rock debris under the influence of gravity, i.e., mass movement, generates a range of phenomena from soil creep, through solifluction,debris flows and rock glaciers to rock falls. Whereas the resultant forms of these phenomena are different, common elements in the mechanics of movement are utilized in the basic interpretation of the processes of formation. Measurements of morphologic variables provide data for deductive analyses of processes that operate too slowly to observe or for processes that generated relict phenomena. External and internal characteristics or rock glacier morphometry and measured rates of motion serve as the basis for the development of a rheological model to explain phenomena classified as rock glaciers. A rock glacier in the Sangre de Cristo Mountains of Southern Colorado, which exhibits a large number of ridges and furrows and lichen bare fronts of lobes, suggests present day movement. A strain-net established on the surface provides evidence of movement characteristics. These data plus morphologic and fabric data suggest two rheological models to explain the flow of this rock glacier. Model one is based upon perfect plastic flow and model two is based upon stratified fluid movement with viscosity changing with depth. These models permit a better understanding of the movement mechanics and demonstrate that catastrophic events and slow creep contribute to the morphologic characteristics of this rock glacier.

Giardino, J.R.; Vitek, J.D.; Hoskins, E.R.

1985-01-01

280

Analysis of meteorological data and the surface energy balance of Keqicar Glacier, Tien Shan, China  

NASA Astrophysics Data System (ADS)

Northwestern China currently experiences a climate change with fundamental consequences for the hydrological cycle. In the strongly arid region where water resources are essential for agriculture and food production, glaciers represent important water resources, contributing significantly to streamflow. The debris is an important glaciological feature of the region and has major impact on melt rates. It is essential to understand and quantify the interaction of climate and sub-debris melt in order to assess the current situation and to predict future water yield. Note that the surface energy balance determines glacier melt. However, little is known about the variability characteristics of the surface energy fluxes in this region. For this reason, we set up two automatic weather stuation (AWSs) in the ablation area of Keqicar Glacier. Keqicar Glacier is located in the Tarim River basin (largest inland river basin in China), southwestern Tien Shan, China. It is a representative debris-covered glacier with a length of 26.0 km and a total surface area of 83.6 km2. The thickness of the debris layer varies from 0.0 to 2.50 m in general. In some places large rocks are piled up to several meters. In this study, we report on analysis of meteorological data for the period 1 July-13 September 2003, from two automatic weather stations, aimed at studying the relationship between climate and ablation. One station is located on the lower part of the ablation area where the glacier is covered by debris layer, and the other near the equilibrium line altitude (ELA). All sensors were sampled every 10 seconds, and data were stored as hourly averages. The stations were visited regularly for maintenance at two weeks intervals depending on the weather conditions and location of the AWS. A total of 17 ablation stakes were drilled into the glacier at different elevations to monitor glacier melt during the study period. Readings were taken regularly in connection with AWS maintenance. The weather station on the glacier measured an average temperature of 2.6 C (at 2m height above surface). The lapse rate of air temperature is close to the standard free atmospheric lapse rate (0.6 C per 100m), which shows the cold effect of glacier is not significant. The local mountain-valley winds is significant, the speed of which is 2.3 m s-1 (at 2m height). Glacier is dominated by the convectional precipitation, 75% of which occurs in day time. The ablation stakes indicate a specific mass balance of -2.5 m w.e. between 1 July and 13 September. The specific mass balance calculated from the surface energy balance, -2.6 m w.e., is in close correspondence to this. The thermal processes on the debris layer are quite different from those on bare ice or snow. The main physical characteristics of the debris layer are the thermal conductivity and albedo that control heat conduction to the ice-debris interface. Net radiation is the main melt energy whether the debris layer is taken into consideration or not, which is lager between July and the middle of August, and then decreases. This is coincides with the glacier ablation. On the debris-covered area, the sensible- and latent-heat fluxes contribute 19.6% of the melt energy, higher than that on the debris-free ice (4.1%). Hence, due to the existing debris layer, the ablation shows a significant spatial distribution.

Zhang, Y.; Liu, S.; Fujita, K.; Han, H.; Li, J.

2009-04-01

281

What Influences Climate and Glacier Change in the Southwestern China?  

NASA Technical Reports Server (NTRS)

The subject of climate change in the areas of the Tibetan Plateau (TP) and the Himalayas has taken on increasing importance because of available water resources from their mountain glaciers. Many of these glaciers over the region have been retreating, while some are advancing and stable. Other studies report that some glaciers in the Himalayas show acceleration on their shrinkage. However, the causes of the glacier meltings are still difficult to grasp because of the complexity of climatic change and its influence on glacier issues. However, it is vital that we pursue further study to enable the future prediction on glacier changes.

Yasunari, Teppei J.

2012-01-01

282

Controls on advance of tidewater glaciers: Results from numerical modeling applied to Columbia Glacier  

Microsoft Academic Search

A one-dimensional numerical ice flow model is used to study the advance of a tidewater glacier into deep water. Starting with ice-free conditions, the model simulates glacier growth at higher elevations followed by advance on land to the head of the fjord. Once the terminus reaches a bed below sea level, calving is initiated. A series of simulations was carried

F. M. Nick; C. J. van der Veen; J. Oerlemans

2007-01-01

283

Modeled Climate-Induced Glacier Change in Glacier National Park, 18502100  

Microsoft Academic Search

mate change. We determined the melt rate and spatial distribution of glaciers under two possible future climate scenarios, one based on carbon dioxide-induced global warming and the other on a linear temperature extrapolation. Under the former scenario, all glaciers in the basin will dis-appear by the year 2030, despite predicted increases in precipitation; under the latter, melting is slower. Using

MYRNA H. P. HALL; DANIEL B. FAGRE

2003-01-01

284

Climate sensitivity of Tibetan Plateau glaciers - past and future implications  

NASA Astrophysics Data System (ADS)

The Tibetan Plateau is one of the most extensively glaciated, non-Polar regions of the world, and its mountain glaciers are the primary source of melt water for several of the largest Asian rivers. During glacial cycles, Tibetan Plateau glaciers advanced and retreated multiple times, but remained restricted to the highest mountain areas as valley glaciers and ice caps. Because glacier extent is dominantly controlled by climate, the past extent of Tibetan glaciers provide information on regional climate. Here we present a study analyzing the past maximum extents of glaciers on the Tibetan Plateau with the output of a 3D glacier model, in an effort to quantify Tibetan Plateau climate. We have mapped present-day glaciers and glacial landforms deposited by formerly more extensive glaciers in eight mountain regions across the Tibetan Plateau, allowing us to define present-day and past maximum glacier outlines. Using a high-resolution (250 m) higher-order glacier model calibrated against present-day glacier extents, we have quantified the climate perturbations required to expand present-day glaciers to their past maximum extents. We find that a modest cooling of at most 6C for a few thousand years is enough to attain past maximum extents, even with 25-75% precipitation reduction. This evidence for limited cooling indicates that the temperature of the Tibetan Plateau remained relatively stable over Quaternary glacial cycles. Given the significant sensitivity to temperature change, the expectation is perhaps that a future warmer climate might result in intense glacier reduction. We have tested this hypothesis and modeled the future glacier development for the three mountain regions with the largest present-day glacier cover using a projected warming of 2.8 to 6.2C within 100 years (envelope limits from IPCC). These scenarios result in dramatic glacier reductions, including 24-100% ice volume loss after 100 years and 77-100% ice volume loss after 300 years.

Heyman, Jakob; Hubbard, Alun; Stroeven, Arjen P.; Harbor, Jonathan M.

2013-04-01

285

The application of artificial neural networks to simulate meltwater runoff of Keqikaer Glacier, south slope of Mt. Tuomuer, western China  

NASA Astrophysics Data System (ADS)

Because glacial melting provides a significant amount of surface water resources, especially in cold arid regions, it is critical that effective methods be developed for predicting their behavior. Glacier runoff differs from other types of stream flows, being characterized by large diurnal fluctuations, with maximum discharge during the summer months. Moreover, the size and remoteness of glaciers makes them difficult to study directly. Hence, developing effective modeling techniques is our best hope for understanding and predicting glacial melting phenomena. In the past, physics-based models have been used with some success. In this study, conducted in 2003 and 2004 on the Keqikaer Glacier on the south slope of Mt. Tuomuer, however, we used the newer artificial neural networks (ANNs) modeling technique. As the input nerve cell, we used the hourly wind speed, precipitation, air temperature, radiation balance, and ground temperature; the output nerve cell was the diurnal runoff at the glacial terminus. We then analyzed the simulated results under different scenarios by varying the input-nerve-cell parameters. It was found that ANN can simulate the process of glacier meltwater runoff successfully when basic parameters such as air temperature, precipitation and radiation balance are few. The results indicate that ANN can simulate the process of glacial meltwater runoff quite well, and that meteorological variables could in fact be used successfully to simulate glacier meltwater runoff using the ANN method.

Caiping, Chen; Yongjian, Ding

2009-06-01

286

Can shrubs help to reconstruct historical glacier retreats?  

NASA Astrophysics Data System (ADS)

In the 21st century, most of the worlds glaciers are expected to retreat due to further global warming. The range of this predicted retreat varies widely as a result of uncertainties in climate and glacier models. To calibrate and validate glacier models, past records of glacier mass balance are necessary, which often only span several decades. Long-term reconstructions of glacier mass balance could increase the precision of glacier models by providing the required calibration data. Here we show the possibility of applying shrub growth increments as an on-site proxy for glacier summer mass balance, exemplified by Salix shrubs in Finse, Norway. We further discuss the challenges which this method needs to meet and address the high potential of shrub growth increments for reconstructing glacier summer mass balance in remote areas.

Buras, Allan; Hallinger, Martin; Wilmking, Martin

2012-12-01

287

Columbia Glacier, Alaska, 1986-2011 - Duration: 0:29.  

NASA Video Gallery

The Columbia Glacier in Alaska is one of many vanishing around the world. Glacier retreat is one of the most direct and understandable effects of climate change. The consequences of the decline in ...

288

Pine Island Glacier, Antarctica, MISR Multi-angle Composite  

Atmospheric Science Data Center

article title: Pine Island Glacier, Antarctica, MISR Multi-angle Composite ... iceberg has finally separated from the calving front of Antarctica's Pine Island Glacier. Scientists first detected a rift in the ...

2013-12-17

289

Rapid Thinning of a Lake Calving Glacier: Yakutat Glacier, Southeast Alaska  

NASA Astrophysics Data System (ADS)

Calving glaciers around the world have recently undergone a rapid retreat and are important contributors to global sea level rise. Due to their greatly increased mass loss, tidewater glaciers in particular have long received much attention, whereas lake calving glaciers have just been identified as significant contributors. In southeast Alaska, numerous glaciers have experienced rapid retreat and significant thinning during the last several decades. To better understand the causes for these rapid changes we have focused on Yakutat Glacier, a lake calving glacier in southeast Alaska. Yakutat Glacier is part of the Yakutat Ice field and drains into Harlequin Lake, which has depths of over 300 m at the calving face. The ice field covers an area of 668 sq km and lies in a maritime area off the coast of the Gulf of Alaska. The average precipitation in the nearby town of Yakutat is over 3800 mm per year. However, the ice field divide is essentially at or below the current equilibrium line altitude (ELA) of 800 - 900 m for this region, thereby ensuring the glacier will continue to thin, provided the current trend of regional warming does not reverse. The ongoing thinning continues to lower the glaciers average elevation, increasing its average ablation, even under constant climate. This forms a positive feedback loop that is known as the Bovardsson effect. In addition, radio echo sounding shows much of the glacier base near or below sea level, indicating that lake calving will remain playing a role in the retreat. We obtained a 40 m-grid digital elevation model (DEM) derived from September 3, 2007 SPOT imagery and obtained under the IPY SPIRIT program. We used August 26, 2007 laser altimetry profiles to check the accuracy of the DEM and found a mean difference of 2 m (DEM greater) with a standard deviation of 2.3 m. We differenced this DEM from a DEM from the February 2000 Shuttle Radar Topography Mission to determine the extent of the volume change and thinning. During this period, the Yakutat Ice field lost about 22.4 7.5 cubic km of ice, with thinning rates increasing down glacier, especially towards the glacier's grounding line. Just up glacier from this grounding line, we found elevation changes of over 10 m per year. The same trend is visible in a comparison between the 2007 Spot DEM and a July 2009 DEM generated from photogrammetry imagery. Little change in surface elevation occurred over the 2-km-long floating tongue during this time period, but recently the entire floating tongue has started to disintegrate.

Truessel, B.; Motyka, R. J.; Larsen, C. F.; Truffer, M.

2010-12-01

290

Columbia Glacier, Alaska: changes in velocity 1977-1986  

USGS Publications Warehouse

The Columbia Glacier, a grounded, iceberg-calving tidewater glacier near Valdez, Alaska, began to retreat about 1977. Drastic retreat occurred in 1984, and by early 1986, retreat amounted to 2km. The glacier has thinned more than 100m since 1974 at a point 4km behind the 1974 terminus position. Between 1977 and 1985 the lower glacier ice velocity increased from 3-8m/d to 10-15m/d. -from Authors

Krimmel, R.M.; Vaughn, B.H.

1987-01-01

291

Glacier Bay, Alaska, from the Ground, Air and Space  

NSDL National Science Digital Library

This video contains a mix of live action video, stills, and computer animations of the Glacier Bay National Park in Glacier Bay, Alaska. Satellite mapping and imagery are used to show changes in the Glacier Bay area over a period of several years. Specific image processing techniques are discussed in relation to determining the evolution of glacier terminus points and in obtaining elevation data and how it is used to create fly-by visualizations of the area.

Cindy Starr

1996-02-23

292

Measuring Greenland Glacier Dynamics with Remotely Sensed Data  

E-print Network

Measuring Greenland Glacier Dynamics with Remotely Sensed Data Steve Foga University of Kansas, Geography M.A. Student Photo by: Phil Pasquini The importance of studying glacier ice Study area Difference in ice velocity of Helheim Glacier... in 2000 [A] and 2004-5 [B]. [Howat et. al., 2005]. Helheim Glacier System GIS Workflow 1. Download 2. Mosaic 3. Project 4. Subset (or clip) ____________________________________________________________________________ 5. Repeat 1-4 for NIR 8...

Foga, Steve

2013-01-15

293

Dendrochronology and Late Holocene History of Bering Piedmont Glacier, Alaska  

Microsoft Academic Search

Fluctuations of the piedmont lobe of Bering Glacier and its sublobe Steller Glacier over the past two millennia are reconstructed using 34 radiocarbon dates and tree-ring data from 16 sites across the glaciers' forelands. The general sequence of glacial activity is consistent with well-dated fluctuations of tidewater and land-terminating glaciers elsewhere along the Gulf of Alaska. Extensive forested areas along

Gregory C. Wiles; Austin Post; Ernest H. Muller; Bruce F. Molnia

1999-01-01

294

Antarctic glaciers shrinking due to ice shelf collapse  

NSDL National Science Digital Library

Mass and velocity measurements taken from satellites and airplanes between 1995 and 2004 were studied to determine if glaciers on the West Antarctic Peninsula were growing or shrinking. It was found that loss of glacier mass from melting and movement into the ocean exceeded snowfall accumulation for several glaciers on the peninsula. The authors propose that as the region continues to warm, the Wordie Bay glaciers will melt more quickly, causing sea level to rise.

Rignot et al.

295

Distinct patterns of seasonal Greenland glacier velocity  

PubMed Central

Predicting Greenland Ice Sheet mass loss due to ice dynamics requires a complete understanding of spatiotemporal velocity fluctuations and related control mechanisms. We present a 5?year record of seasonal velocity measurements for 55 marine-terminating glaciers distributed around the ice sheet margin, along with ice-front position and runoff data sets for each glacier. Among glaciers with substantial speed variations, we find three distinct seasonal velocity patterns. One pattern indicates relatively high glacier sensitivity to ice-front position. The other two patterns are more prevalent and appear to be meltwater controlled. These patterns reveal differences in which some subglacial systems likely transition seasonally from inefficient, distributed hydrologic networks to efficient, channelized drainage, while others do not. The difference may be determined by meltwater availability, which in some regions may be influenced by perennial firn aquifers. Our results highlight the need to understand subglacial meltwater availability on an ice sheet-wide scale to predict future dynamic changes. Key Points First multi-region seasonal velocity measurements show regional differences Seasonal velocity fluctuations on most glaciers appear meltwater controlled Seasonal development of efficient subglacial drainage geographically divided

Moon, Twila; Joughin, Ian; Smith, Ben; van den Broeke, Michiel R; van de Berg, Willem Jan; Nol, Brice; Usher, Mika

2014-01-01

296

Exploration of Uncertainty in Glacier Modelling  

NASA Technical Reports Server (NTRS)

There are procedures and methods for verification of coding algebra and for validations of models and calculations that are in use in the aerospace computational fluid dynamics (CFD) community. These methods would be efficacious if used by the glacier dynamics modelling community. This paper is a presentation of some of those methods, and how they might be applied to uncertainty management supporting code verification and model validation for glacier dynamics. The similarities and differences between their use in CFD analysis and the proposed application of these methods to glacier modelling are discussed. After establishing sources of uncertainty and methods for code verification, the paper looks at a representative sampling of verification and validation efforts that are underway in the glacier modelling community, and establishes a context for these within overall solution quality assessment. Finally, an information architecture and interactive interface is introduced and advocated. This Integrated Cryospheric Exploration (ICE) Environment is proposed for exploring and managing sources of uncertainty in glacier modelling codes and methods, and for supporting scientific numerical exploration and verification. The details and functionality of this Environment are described based on modifications of a system already developed for CFD modelling and analysis.

Thompson, David E.

1999-01-01

297

Modeled climate-induced glacier change in Glacier National Park, 1850-2100  

USGS Publications Warehouse

The glaciers in the Blackfoot-Jackson Glacier Basin of Glacier National Park, Montana, decreased in area from 21.6 square kilometers (km2) in 1850 to 7.4 km2 in 1979. Over this same period global temperatures increased by 0.45??C (?? 0. 15??C). We analyzed the climatic causes and ecological consequences of glacier retreat by creating spatially explicit models of the creation and ablation of glaciers and of the response of vegetation to climate change. We determined the melt rate and spatial distribution of glaciers under two possible future climate scenarios, one based on carbon dioxide-induced global warming and the other on a linear temperature extrapolation. Under the former scenario, all glaciers in the basin will disappear by the year 2030, despite predicted increases in precipitation; under the latter, melting is slower. Using a second model, we analyzed vegetation responses to variations in soil moisture and increasing temperature in a complex alpine landscape and predicted where plant communities are likely to be located as conditions change.

Hall, M.H.P.; Fagre, D.B.

2003-01-01

298

Contrasting responses of Central Asian rock glaciers to global warming.  

PubMed

While the responses of Tien Shan glaciers - and glaciers elsewhere - to climatic changes are becoming increasingly well understood, this is less the case for permafrost in general and for rock glaciers in particular. We use a novel approach to describe the climate sensitivity of rock glaciers and to reconstruct periods of high and low rock glacier activity in the Tien Shan since 1895. Using more than 1500 growth anomalies from 280 trees growing on rock glacier bodies, repeat aerial photography from Soviet archives and high-resolution satellite imagery, we present here the world's longest record of rock glacier movements. We also demonstrate that the rock glaciers exhibit synchronous periods of activity at decadal timescales. Despite the complex energy-balance processes on rock glaciers, periods of enhanced activity coincide with warm summers, and the annual mass balance of Tuyuksu glacier fluctuates asynchronously with rock glacier activity. At multi-decadal timescales, however, the investigated rock glaciers exhibit site-specific trends reflecting different stages of inactivation, seemingly in response to the strong increase in air temperature since the 1970s. PMID:25657095

Sorg, Annina; Kb, Andreas; Roesch, Andrea; Bigler, Christof; Stoffel, Markus

2015-01-01

299

Contrasting responses of Central Asian rock glaciers to global warming  

PubMed Central

While the responses of Tien Shan glaciers and glaciers elsewhere to climatic changes are becoming increasingly well understood, this is less the case for permafrost in general and for rock glaciers in particular. We use a novel approach to describe the climate sensitivity of rock glaciers and to reconstruct periods of high and low rock glacier activity in the Tien Shan since 1895. Using more than 1500 growth anomalies from 280 trees growing on rock glacier bodies, repeat aerial photography from Soviet archives and high-resolution satellite imagery, we present here the world's longest record of rock glacier movements. We also demonstrate that the rock glaciers exhibit synchronous periods of activity at decadal timescales. Despite the complex energy-balance processes on rock glaciers, periods of enhanced activity coincide with warm summers, and the annual mass balance of Tuyuksu glacier fluctuates asynchronously with rock glacier activity. At multi-decadal timescales, however, the investigated rock glaciers exhibit site-specific trends reflecting different stages of inactivation, seemingly in response to the strong increase in air temperature since the 1970s. PMID:25657095

Sorg, Annina; Kb, Andreas; Roesch, Andrea; Bigler, Christof; Stoffel, Markus

2015-01-01

300

GLACIER MONITORING FROM ASTER IMAGERY: ACCURACY AND APPLICATIONS  

E-print Network

field for Tasman glacier, New Zealand, was successfully derived from repeated ASTER orthoimages and Reflection Radiometer) on board the Terra satellite offers new possibilities for worldwide glacier monitoringGLACIER MONITORING FROM ASTER IMAGERY: ACCURACY AND APPLICATIONS A. Kb1 , C. Huggel1 , F. Paul1

Oldenburg, Carl von Ossietzky Universitt

301

HYDROLOGICAL REGIME OF GLACIERS IN THE ALAY RANGE, CENTRAL ASIA  

Microsoft Academic Search

The Alay range is a major region of contemporary glacierization in Central Asia, where 1 088 glaciers cover a territory of 1 030 km2. The volume of ice concentrated within the Alay region is about 35 km 3. The main geographical regularity in the glacierization of the Alay range is its gradual dimensional diminution in a west to east direction.

V. F. SUSLOY; A. A. AKBAROV

302

Complex and shifting Himalayan glacier changes point to complex  

E-print Network

processes Dec. 14, 2009 JSK Satellite-era glacier changes in High Asia Jeffrey S. Kargel*, Richard Armstrong statements by Kargel that the glaciers will not disappear by 2035, but that they are melting rapidly in someComplex and shifting Himalayan glacier changes point to complex and shifting climate driving

303

Chemical weathering in the foreland of a retreating glacier  

Microsoft Academic Search

Chemical denudation rates and strontium isotope ratios in streams vary substantially and systematically in the foreland of the retreating Bench Glacier in south-central Alaska. To study weathering of young glacier sediments, we sampled 12 streams draining a chronosequence of till and moraine soils derived from Cretaceous metagraywacke-metapelite bedrock. Both sediment age and vegetation cover increase with distance from the glacier.

Suzanne Prestrud Anderson; James I. Drever; Carol D. Frost; Pete Holden

2000-01-01

304

Chemical weathering in the foreland of a retreating glacier  

Microsoft Academic Search

Chemical denudation rates and strontium isotope ratios in streams vary substantially and systematically in the foreland of the retreating Bench Glacier in south-central Alaska. To study weathering of young glacier sediments, we sampled 12 streams draining a chronosequence of till and moraine soils derived from Cretaceous metagraywackemetapelite bedrock. Both sediment age and vegetation cover increase with distance from the glacier.

Suzanne Prestrud Anderson; James I Drever; Carol D Frost; Pete Holden

2000-01-01

305

Extracting a Climate Signal from 169 Glacier Records  

Microsoft Academic Search

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 century.

J. Oerlemans

2005-01-01

306

The physical basis of glacier volume-area scaling  

Microsoft Academic Search

Ice volumes are known for only a few of the roughly 160,000 glaciers worldwide but are important components of many climate and sea level studies which require water flux estimates. A scaling analysis of the mass and momentum conservation equations shows that glacier volumes can be related by a power law to more easily observed glacier surface areas. The relationship

David B. Bahr; Mark F. Meier; Scott D. Peckham

1997-01-01

307

Rapid disintegration of Alpine glaciers observed with satellite data  

Microsoft Academic Search

Analyses of multispectral satellite data indicate accelerated glacier decline around the globe since the 1980s. By using digitized glacier outlines inferred from the 1973 inventory and Landsat Thematic Mapper (TM) satellite data from 1985 to 1999, we obtained area changes of about 930 Alpine glaciers. The 18% area reduction as observed for the period 1985 to 1999 (-1.3% a-1) corresponds

Frank Paul; Andreas Kb; Max Maisch; Tobias Kellenberger; Wilfried Haeberli

2004-01-01

308

Melting Alpine Glaciers Enrich High-Elevation Lakes with Reactive  

E-print Network

Melting Alpine Glaciers Enrich High-Elevation Lakes with Reactive Nitrogen J A S M I N E E . S A R received May 26, 2010. Accepted May 28, 2010. Alpine glaciers have receded substantially over the last. Our results demonstrate that the presence of glaciers on alpine watersheds more strongly influences NO

Williamson, Craig E.

309

Losing a Legacy: A photographic story of disappearing glaciers  

E-print Network

Losing a Legacy: A photographic story of disappearing glaciers W.C. Alden photo, GNP Archives B. Reardon photo, USGS Dan Fagre & Lisa McKeon, USGS G alle r y G ui de ShepardGlacier 1 9 1 3 2 0 0 5 #12. The following collection of repeat photographs of glaciers has been assembled and re-photographed by USGS

310

Glacier: Highly durable, decentralized storage despite massive correlated failures  

E-print Network

Glacier: Highly durable, decentralized storage despite massive correlated failures Andreas be considered when attempting to provide highly durable storage. In this paper, we describe Glacier failures. Glacier is designed to aggressively minimize the cost of this redun- dancy in space and time

Pennsylvania, University of

311

Seasonal glacier melt contribution to streamflow Neil Schaner  

E-print Network

1 Seasonal glacier melt contribution to streamflow Neil Schaner Department of Civil of Washington Seattle, WA 98195 dennisl@u.washington.edu #12;2 Ongoing and projected future changes in glacier. However, the current magnitude of glacier contributions to river runoff is not well known, nor

Washington at Seattle, University of

312

Glacier melt contribution to streamflow1 Neil Schaner1  

E-print Network

1 Glacier melt contribution to streamflow1 Neil Schaner1 , Nathalie Voisin2 , Bart Nijssen1 12 * Corresponding author13 Abstract. Ongoing and projected future changes in glacier extent and water storage14 globally have led to concerns about the implications for water supplies. Glacier15

Washington at Seattle, University of

313

Glacier: A Query-to-Hardware Compiler Rene Mueller  

E-print Network

Glacier: A Query-to-Hardware Compiler Rene Mueller rene.mueller@inf.ethz.ch Jens Teubner jens systems. In this demonstration we show Glacier, a library and a compiler that can be employed to implement streaming queries as hardware circuits on FPGAs. Glacier consists of a library of compositional hardware

Teubner, Jens

314

Latest Pleistocene and Holocene glacier variations in the European Alps  

Microsoft Academic Search

In the Alps, climatic conditions reflected in glacier and rock glacier activity in the earliest Holocene show a strong affinity to conditions in the latest Pleistocene (Younger Dryas). Glacier advances in the Alps related to Younger Dryas cooling led to the deposition of Egesen stadial moraines. Egesen stadial moraines can be divided into three or in some cases even more

Susan Ivy-Ochs; Hanns Kerschner; Max Maisch; Marcus Christl; Peter W. Kubik; Christian Schlchter

2009-01-01

315

OPTICAL FLOW FOR GLACIER MOTION ESTIMATION Christoph Vogel1  

E-print Network

The motion observed at the surface of a glacier is due to gravi- tational deformation of the ice and sliding of the surface flow field. Observed temporal variations in glacier motion range from hours to seasons and decadesOPTICAL FLOW FOR GLACIER MOTION ESTIMATION Christoph Vogel1 , Andreas Bauder2 and Konrad Schindler1

Schindler, Konrad

316

Widespread Alaska glacier retreat likely not due to climate change  

NASA Astrophysics Data System (ADS)

Alaska's Columbia Glacier, which has shed half its mass since 1957, is a dramatic example of how quickly glaciers can shrink. Yet while Columbia has shown a huge decline, a new analysis by McNabb and Hock has found that other glaciers in the region have retreated far less, or even advanced, over the past 6 decades.

Schultz, Colin

2014-06-01

317

WATER FLOW THROUGH TEMPERATE GLACIERS Andrew G. Fountain1  

E-print Network

WATER FLOW THROUGH TEMPERATE GLACIERS Andrew G. Fountain1 Department of Geology Portland State, Washington Abstract. Understanding water movement through a glacier is fundamental to several critical issues glacierized drainage basins. To this end we have synthesized a conceptual model of water movement through

Fountain, Andrew G.

318

Contrasting responses of Central Asian rock glaciers to global warming  

NASA Astrophysics Data System (ADS)

While the responses of Tien Shan glaciers - and glaciers elsewhere - to climatic changes are becoming increasingly well understood, this is less the case for permafrost in general and for rock glaciers in particular. We use a novel approach to describe the climate sensitivity of rock glaciers and to reconstruct periods of high and low rock glacier activity in the Tien Shan since 1895. Using more than 1500 growth anomalies from 280 trees growing on rock glacier bodies, repeat aerial photography from Soviet archives and high-resolution satellite imagery, we present here the world's longest record of rock glacier movements. We also demonstrate that the rock glaciers exhibit synchronous periods of activity at decadal timescales. Despite the complex energy-balance processes on rock glaciers, periods of enhanced activity coincide with warm summers, and the annual mass balance of Tuyuksu glacier fluctuates asynchronously with rock glacier activity. At multi-decadal timescales, however, the investigated rock glaciers exhibit site-specific trends reflecting different stages of inactivation, seemingly in response to the strong increase in air temperature since the 1970s.

Sorg, Annina; Kb, Andreas; Roesch, Andrea; Bigler, Christof; Stoffel, Markus

2015-02-01

319

Subglacial melting of glaciers by catchment streams is a missing link in temperate glacier mass balance  

NASA Astrophysics Data System (ADS)

The influence of snowmelt and rain water on subglacial hydrology and glacier mass balance of temperate valley glaciers is poorly understood. We present a thermo-hydraulic melt model to improve understanding of the potential influence that streams sourced from snowmelt and rain have on the subglacial hydrology and melting of the high-precipitation Franz Josef Glacier, New Zealand. The model simulates conduit expansion due to melting caused by heat advection and contraction to due ice deformation at an hourly time-step to obtain an annual melt rate along the length of individual subglacial conduits fed from terrestrial streams that enter the glacier from the ice-free sub-catchments surrounding it. These streams are fed by snowmelt and rainfall that enter the glacier well above 0C (up to ~10C at low altitudes). Our model is calibrated using terrestrial stream temperature data and is validated with field measurements of surface and proglacial meltwater temperatures, as well as internal water flow velocities. Modelled outputs based on the best available data from measurements and observations indicate that streams entering the Franz Josef Glacier contribute an estimated 7% to the total glacier melt. This is the equivalent of more than twice the surface rainfall heat flux, which shows that rain and snowmelt may melt significant quantities of ice within a glacier. Not accounting for this melting mechanism in glaciological models where streams enter glaciers may lead to: 1) an incorrect characterisation of the subglacial hydrological drainage system; and 2) a potentially serious bias error in mass balance estimations. The second implication is fundamentally important for model robustness given that glaciological models are increasingly being used to predict the effects of future climate change.

Alexander, David; Shulmeister, James; Davies, Tim; Callow, Nik

2013-04-01

320

Malaspina Glacier, Alaska, Anaglyph with Landsat Overlay  

NASA Technical Reports Server (NTRS)

This anaglyph view of Malaspina Glacier in southeastern Alaska was created from a Landsat satellite image and an elevation model generated by the Shuttle Radar Topography Mission (SRTM). Malaspina Glacier is considered the classic example of a piedmont glacier. Piedmont glaciers occur where valley glaciers exit a mountain range onto broad lowlands, are no longer laterally confined, and spread to become wide lobes. Malaspina Glacier is actually a compound glacier, formed by the merger of several valley glaciers, the most prominent of which seen here are Agassiz Glacier (left) and Seward Glacier (right). In total, Malaspina Glacier is up to 65 kilometers (40 miles) wide and extends up to 45 kilometers (28 miles) from the mountain front nearly to the sea.

Glaciers erode rocks, carry them down slope, and deposit them at the edge of the melting ice, typically in elongated piles called moraines. The moraine patterns at Malaspina Glacier are quite spectacular in that they have huge contortions that result from the glacier crinkling as it gets pushed from behind by the faster-moving valley glaciers.

Numerous other features of the glaciers and the adjacent terrain are clearly seen when viewing this image at full resolution. The series of tonal arcs on Agassiz Glacier's extension onto the piedmont are called 'ogives.' These arcs are believed to be seasonal features created by deformation of the glacier as it passes over bedrock irregularities at differing speeds through the year. Assuming one light-and-dark ogive pair per year, the rate of motion of the glacial ice can be estimated (in this case, about 200 meters per year where the ogives are most prominent). Just to the west, moraine deposits abut the eroded bedrock terrain, forming a natural dam that has created a lake. Near the northwest corner of the scene, a recent landslide has deposited rock debris atop a small glacier. Sinkholes are common in many areas of the moraine deposits. The sinkholes form when blocks of ice are caught up in the deposits and then melt, locally collapsing the deposit. The combination of Landsat imagery and SRTM elevation data used in this stereoscopic display is very effective in visualizing these and other features of this terrain.

The stereoscopic effect of this anaglyph was created by registering a Landsat image to the SRTM elevation model and then generating two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter.

Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and substantially helps in analyzing the large and growing Landsat image archive.

Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on February 11, 2000. The mission used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar that flew twice on the Space Shuttle Endeavour in 1994. The Shuttle Radar Topography Mission was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC. Size: 55 x 55 kilometers (34 x 34 miles) Location: 60 deg N latitude, 140 deg W longitude Orientation: North at top Image Data: Landsat Thematic Mapper visible and infrared band mix Original Data Resolution: SRTM 1 arcsecond (30 mete

2003-01-01

321

Global-scale modeling of glacier mass balances for water resources assessments: Glacier mass changes between 1948 and 2006  

Microsoft Academic Search

Glaciers play an important role for freshwater resources, but in global-scale freshwater assessments, their impact on river flows has not yet been taken into account. As a first step, we developed a global glacier model that can be coupled to global land surface and hydrological models. With a spatial resolution of 0.5 by 0.5, the glacier model HYOGA computes glacier

Yukiko Hirabayashi; Petra Dll; Shinjiro Kanae

2010-01-01

322

Comparative metagenome analysis of an Alaskan glacier.  

PubMed

The temperature in the Arctic region has been increasing in the recent past accompanied by melting of its glaciers. We took a snapshot of the current microbial inhabitation of an Alaskan glacier (which can be considered as one of the simplest possible ecosystems) by using metagenomic sequencing of 16S rRNA recovered from ice/snow samples. Somewhat contrary to our expectations and earlier estimates, a rich and diverse microbial population of more than 2,500 species was revealed including several species of Archaea that has been identified for the first time in the glaciers of the Northern hemisphere. The most prominent bacterial groups found were Proteobacteria, Bacteroidetes, and Firmicutes. Firmicutes were not reported in large numbers in a previously studied Alpine glacier but were dominant in an Antarctic subglacial lake. Representatives of Cyanobacteria, Actinobacteria and Planctomycetes were among the most numerous, likely reflecting the dependence of the ecosystem on the energy obtained through photosynthesis and close links with the microbial community of the soil. Principal component analysis (PCA) of nucleotide word frequency revealed distinct sequence clusters for different taxonomic groups in the Alaskan glacier community and separate clusters for the glacial communities from other regions of the world. Comparative analysis of the community composition and bacterial diversity present in the Byron glacier in Alaska with other environments showed larger overlap with an Arctic soil than with a high Arctic lake, indicating patterns of community exchange and suggesting that these bacteria may play an important role in soil development during glacial retreat. PMID:24712530

Choudhari, Sulbha; Lohia, Ruchi; Grigoriev, Andrey

2014-04-01

323

Glacier fluctuations in the Kenai Fjords, Alaska, U.S.A.: An evaluation of controls on Iceberg-calving glaciers  

SciTech Connect

The histories of four iceberg-calving outlet-glacier systems in the Kenai Fjords National Park underscore the importance of fiord depth, sediment supply, and fiord geometry on glacier stability. These parameters, in turn, limit the reliability of calving glacier chronologies as records of climatic change. Tree-ring analysis together with radiocarbon dating show that the Northwestern and McCarty glaciers, with large drainage basins, were advancing in concert with nearby land-terminating glaciers about A.D. 600. After an interval of retreat and possible nonclimatically induced extension during the Medieval Warm Period, these ice margins advanced again through the Little Ice Age and then retreated synchronously with the surrounding land-terminating glaciers about A.D. 1900. In contrast, Holgate and Aialik glaciers, with deeper fiords and smaller basins, retreated about 300 yr earlier. Reconstructions of Little Ice Age glaciers suggest that equilibrium-line altitudes of Northwestern and McCarty glaciers were, respectively, 270 and 500 m lower than now. Furthermore, the reconstructions show that these two glaciers were climatically sensitive when at their terminal moranies. However, with ice margins at their present recessional positions and accumulation area ratios between 0.8 and 0.9, only McCarty Glacier shows evidence of advance. Aialik and Holgate glaciers were climatically insensitive during the Little Ice Age maxima and remain insensitive to climate. 40 refs., 7 figs., 2 tabs.

Wiles, G.C. [Columbia Univ., Palisades, NY (United States); Calkin, P.E. [Univ. of New York, Buffalo, NY (United States); Post, A. [Geological Survey, Vashon, WA (United States)

1995-08-01

324

Integration Of Reflectance To Study Glacier Surface Using Landsat 7 ETM+: A Case Study Of The Petermann Glacier In Greenland  

E-print Network

in the Arctic due to climate models that predict Arctic warming and change in mass balance of the glaciers. One from Greenland Ice Sheet and other glaciers (Benn et al., 2007). Rapid retreat followed by a climate change increases the potential of glacier to contribution to sea level rise. (Benn et al., 2007). Fast

Gilbes, Fernando

325

An ALOS-derived glacier inventory of the Bhutan Himalaya  

NASA Astrophysics Data System (ADS)

Glacier inventory provides fundamental information of glacier settings such as number, area, and horizontal/altitudinal distribution, which make possible to study management of water resources, glacial response to climate change, and glacier-related hazards. In the Bhutan Himalaya, heavily debris-covered surface and seasonal snow cover under the humid climate hamper automated mapping of glaciers. We present a novel glacier inventory manually delineated from high resolution (2.5 m) ALOS-PRISM images along the Bhutan Himalaya including Tibetan side. We delineated 1273 glaciers with area of 1408.3 km2, in which 210 debris-covered glaciers with area of 951.2 km2 were identified. Scatter plot of top and terminus altitudes of these glaciers shows that the termini of debris-covered glaciers tend to be located at lower altitude than those of debris-free glaciers. Classifying surface aspect into eight directions, surface of the debris-free glaciers tends to be exposed northward (16.7%) while the southwestward surface is minimum (9.2%). No remarkable aspect tendency is found for the debris-covered glaciers. We compare the locations of debris-free glaciers with annual precipitation of TRMM 3B43 data. Median altitude, at which glacier surface is divided into two equal areas obviously increases northward (toward Tibet) along latitude. Additionally the median altitude averaged over basin scale (~2500 km2) shows a significant negative correlation against the annual precipitation (r= -0.48, p< 0.05). Our results suggest that the high latitudinal gradient of annual precipitation crossing the Bhutan Himalaya contrasts the glacier altitudinal distribution within a scale of 100 km.

Nagai, Hiroto; Fujita, Koji; Nuimura, Takayuki; Sakai, Akiko

2013-04-01

326

Glacier area and length changes in Norway from repeat inventories  

NASA Astrophysics Data System (ADS)

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.

Winsvold, S. H.; Andreassen, L. M.; Kienholz, C.

2014-06-01

327

Columbia Glacier in 1986; 800 meters retreat  

USGS Publications Warehouse

Columbia Glacier, in Prince William Sound, Alaska, continued its rapid retreat in 1986, with a retreat of 800 m. Average velocity of the lower portion of the glacier, 10 September 1986 to 26 January 1987, was three km/yr, or about one-half of the velocity during similar periods for the previous three years. This reduced velocity is a new development in the progression of the retreat, and if the calving rate follows the pattern of previous years, will result in continued retreat. (Author 's abstract)

Krimmel, R.M.

1987-01-01

328

Glacier surge after ice shelf collapse.  

PubMed

The possibility that the West Antarctic Ice Sheet will collapse as a consequence of ice shelf disintegration has been debated for many years. This matter is of concern because such an event would imply a sudden increase in sea level. Evidence is presented here showing drastic dynamic perturbations on former tributary glaciers that fed sections of the Larsen Ice Shelf on the Antarctic Peninsula before its collapse in 1995. Satellite images and airborne surveys allowed unambiguous identification of active surging phases of Boydell, Sjgren, Edgeworth, Bombardier, and Drygalski glaciers. This discovery calls for a reconsideration of former hypotheses about the stabilizing role of ice shelves. PMID:12624263

De Angelis, Hernn; Skvarca, Pedro

2003-03-01

329

Melting Himalayan Glaciers May Doom Towns  

NSDL National Science Digital Library

This news article describes how mountain lakes in Nepal and Bhutan have become so overfilled by water from melting glaciers that they are in danger of overflowing. Scientists from the United Nations Environment Program (UNEP), along with remote-sensing experts from the International Center for Integrated Mountain Development (ICIMOD), predict that in the next half decade or so, the Himalayas could experience intense flooding as mountain lakes overflow with water from glaciers and snowfields which are melting as a result of gradually rising global temperatures.

330

Glaciers and Global Climate: Field and Remote-Sensing Studies of the Arctic  

NASA Technical Reports Server (NTRS)

Glaciers are important indicators of global climate. Glacier recession, as observed from space and in the field, has been occurring for about 100 years. The present extent of glaciers and glaciers in the last Ice Age will be discussed. I will show slides of field work on glaciers and show instruments used to measure ice and snow. I will discuss reasons for studying glaciers and why remote sensing is important for glacier studies.

Hall, D. K.

1998-01-01

331

Sensitivity of glaciers and small ice caps to greenhouse warming  

SciTech Connect

Recent field programs on glaciers have supplied information that makes simulation of glacier mass balance with meteorological models meaningful. An estimate of world-wide glacier sensitivity based on a modeling study of 12 selected glaciers situated in widely differing climatic regimes shows that for a uniform 1 K warming the area-weighted glacier mass balance will decrease by 0.40 meter per year. This corresponds to a sea-level rise of 0.58 millimeter per year, a value significantly less than earlier estimates.

Oerlemans, J.; Fortuin, J.P.F. (Utrecht Univ. (Netherlands))

1992-10-02

332

Contrasting response of South Greenland glaciers to recent climatic change  

SciTech Connect

A unique geographical configuration of glaciers exists in the Narsarsuaq district of South Greenland. Two large outlet glaciers divide into seven distributaries, such that each glacier system has land-terminating, tidewater-calving, and fresh-water-calving termini. Despite a similar climatic regime, these seven glaciers have exhibited strongly contrasting terminal behavior in historical time, as shown by historical records, aerial photographs, and fieldwork in 1989. The behavior of the calving glaciers cannot be accounted for with reference solely to climatic parameters. The combination of iceberg calving dynamics and topographic control has partially decoupled them from climatic forcing such that their oscillations relate more closely to glaciodynamic than glacioclimatic factors.

Warren, C.R.; Glasser, N.F. (Univ. of Edinburgh, Scotland (United Kingdom))

1992-05-01

333

Prairies in the Prairie State : How Glaciers Shape the Land  

NSDL National Science Digital Library

This hands-on activity demonstrates the abrasive power of glaciers carrying rocks and sand. Its purpose is to illustrate the concept that glaciers change the Earth's surface through the processes of erosion and deposition. Students construct model glaciers by freezing water with sand and pebbles at the bottom to represent the rock fragments carried by a real glacier. They then rub their 'glacier' across rocks of varying hardness to see what happens. Afterwards, they place the ice where it can melt and observe what happens to the sand and pebbles trapped in it. A materials list, procedures, and background information are supplied.

334

On turbulent heat flux contributions to the energy balance at the Opabin Glacier, Yoho National Park, Canada  

NASA Astrophysics Data System (ADS)

Turbulent heat flux and its contribution to energy balance is investigated at two glaciers in the Canadian Rockies. Detailed profile measurements of wind, temperature, and humidity in the lower boundary layer above the Opabin Glacier reveal a predominantly stable boundary layer regime. Wind speeds generally increase with height and temperature profiles are predominantly logarithmic in nature, however humidity profiles do not exhibit the archetypal shape. Roughness lengths derived using the profile method are used to calculate energy balance in fifteen unique models per site. The models perform best at both sites when a constant roughness value is used; however, the median value of all found roughness lengths performs better than mean value which is typically used in current literature. Model results improve when melt is restricted to periods when surface temperature is above 0C, and when atmospheric stability corrections are applied.

Losic, Mira

335

Origin, Evolution, and Preservation of Cold Based Debris Covered Glaciers: Quantifying Sublimation Rates of Ancient Buried Ice in Antarctica  

NASA Astrophysics Data System (ADS)

Growing interest in our planet's climate history has placed a premium on acquiring detailed records of past climate change. Of considerable interest are archives of ancient atmosphere trapped within the debris-covered alpine glaciers of the western Dry Valleys region of Antarctica. The Mullins Valley debris-covered glacier (~8 km in length) is sourced from local snowfall at the steep headwall of the valley. The first 1.2 km of this glacier is generally free of overlying debris except for isolated cobbles and boulders. Thereafter, the ice surface is covered with a thin, continuous sheet of dolerite-rich rubble. Factors that influence the origin and modification of this ice include atmospheric temperature and relative humidity, precipitation, incoming solar radiance, surface albedo, till texture, winds, surface roughness, salts, and secondary ice lenses. We applied a diffusion model to track vapor flux within a sublimation till overlying the Mullins Valley debris-covered glacier, purportedly the world's oldest debris-covered alpine glacier. As input, we used meteorological data from HOBO data loggers that captured climate change and till temperatures. Results show that vapor flows into and out of the sublimation till at rates dependent on the non-linear variation of soil temperature with depth. Sublimation rates along the Mullins Glacier varied as a function of till thickness, local climate (using a calculated regional lapse rate of 0.88C per 100 m), and till texture. Ice loss during the study interval (November 27, 2006 to December 24, 2006) ranged from as high as 2.12 mm for exposed glacier ice in the upper ablation zone, to as low as 0.01 mm for buried ice beneath till >50 cm in thickness. Averaged over the entire ablation zone (6.7 km2), this yields a net ice-surface lowering of 0.32 mm during the study interval. Numerical modeling suggests that a modest ice accumulation rate at the headwall of ~1 cm a-1 appears sufficient to maintain current ice volumes. Overall, our model results are consistent with an inferred Miocene age for distal portions of the Mullins Valley debris-covered glacier and suggests that ancient atmosphere may be preserved in buried glaciers in the western Dry Valleys region.

Kowalewski, D. E.; Marchant, D. R.

2007-12-01

336

Little Ice Age glaciers in Britain: Glacierclimate modelling in the Cairngorm Mountains  

SciTech Connect

It is widely believed that the last glaciers in the British Isles disappeared at the end of the Younger Dryas stadial (12.911.7 cal. kyr BP). Here, we use a glacierclimate model driven by data from local weather stations to show for the first time that glaciers developed during the Little Ice Age (LIA) in the Cairngorm Mountains. Our model is forced from contemporary conditions by a realistic difference in mean annual air temperature of -1.5 degrees C and an increase in annual precipitation of 10%, and confirmed by sensitivity analyses. These results are supported by the presence of small boulder moraines well within Younger Dryas ice limits, and by a dating programme on a moraine in one cirque. As a result, we argue that the last glaciers in the Cairngorm Mountains (and perhaps elsewhere in upland Britain) existed in the LIA within the last few hundred years, rather than during the Younger Dryas.

Stephan Harrison; Ann V. Rowan; Neil F. Glasser; Jasper Knight; Mitchell A. Plummer; Stephanie C. Mills

2014-02-01

337

Mapping the retreat of the Asulkan Glacier in Glacier National Park, British Columbia  

E-print Network

Dendrochronology with Jacolby Dendroclimatology with Markus and Kyla Lichenometry with Erin Moraine #12;190520071918 #12;Site Map #12;DendrochronologyDendrochronology #12;Dendrochronology Tree age lichen size and proximity to glacier snout. #12;Moraine Interpretation 3 Approaches: Dendrochronology

Smith, Dan

338

A complex relationship between calving glaciers and climate  

USGS Publications Warehouse

Many terrestrial glaciers are sensitive indicators of past and present climate change as atmospheric temperature and snowfall modulate glacier volume. However, climate interpretations based on glacier behavior require careful selection of representative glaciers, as was recently pointed out for surging and debris-covered glaciers, whose behavior often defies regional glacier response to climate [Yde and Paasche, 2010]. Tidewater calving glaciers (TWGs)mountain glaciers whose termini reach the sea and are generally grounded on the seaflooralso fall into the category of non-representative glaciers because the regional-scale asynchronous behavior of these glaciers clouds their complex relationship with climate. TWGs span the globe; they can be found both fringing ice sheets and in high-latitude regions of each hemisphere. TWGs are known to exhibit cyclic behavior, characterized by slow advance and rapid, unstable retreat, largely independent of short-term climate forcing. This so-called TWG cycle, first described by Post [1975], provides a solid foundation upon which modern investigations of TWG stability are built. Scientific understanding has developed rapidly as a result of the initial recognition of their asynchronous cyclicity, rendering greater insight into the hierarchy of processes controlling regional behavior. This has improved the descriptions of the strong dynamic feedbacks present during retreat, the role of the ocean in TWG dynamics, and the similarities and differences between TWG and ice sheet outlet glaciers that can often support floating tongues.

Post, A.; O'Neel, S.; Motyka, R.J.; Streveler, G.

2011-01-01

339

Surface change detection in glacier regions using ALOS PALSAR data  

NASA Astrophysics Data System (ADS)

Mountainous glaciers are important water resources in the high mountainous region. The glaciers not only supply water for drinking and agriculture, but also produce energy in hydroelectric power plants to local communities. The recent rapid glacier retreat is at high risk for severe water shortage in the near future. And the melting water of glacier sometimes leads to landslide disaster or glacier lake outburst flood (GLOF). Actually, the debris flow happened and damaged the buildings at the valley of Pacuni glacier in Bolivia in December 2007. Consequently, the monitoring of the glacier regions is very important both to manage water resources and to mitigate the damage from landslide disaster. The Advanced Land Observing Satellite DAICHI (ALOS) has three sensors, two visible imagers and one L-band polarimetric SAR, and has been observing the land surface since 2006. This study discusses the availability of the Phased-Array type L-band Synthetic Aperture Radar (PALSAR) of ALOS for surface change detection in glacier regions in Bolivia. The observation by PALSAR is unaffected by weather. And this characteristic is the most important for the glacier monitoring. Some glaciers and their surrounding mountainous regions are selected as a test sites for this study and many landslides near Pacuni glacier were detected by Differential Interferometric SAR (DInSAR) technique using PALSAR data of ALOS.

Tomiyama, N.; Ono, M.

2010-12-01

340

The altitudinal distribution of snow algae on an Alaska glacier (Gulkana Glacier in the Alaska Range)  

NASA Astrophysics Data System (ADS)

The altitudinal distribution of a snow algal community was investigated on an Alaska glacier (Gulkana Glacier in the Alaska Range) from 1270 to 1770 m a.s.l.. Seven species of snow and ice algae (Chlorophyta and cyanobacteria) were observed on the glacier surface. These species were Chlamydomonas nivalis, Mesotaenium berggrenii, Ancylonema nordenskioldii, Cylindrocystis brbissonii, Raphidonema sp., and two Oscillatoriaceae cyanobacteria. The altitudinal distribution of snow algae was different among the species: Cd. nivalis was distributed on the middle to upper area, M. berggrenii; A. nordenskioldii, and one Oscillatoriaceae cyanobacterium on the middle to lower area; Raphidonema sp. on the middle area; and Cyl. brbissonii and one Oscillatoriaceae cyanobacterium on the lower area. The total cell concentration and the cell volume biomass of the snow algae ranged from 44 103 to 99 105 cells ml-1 and from 33 to 2211 l m-2 respectively. The cell volume biomass changed with altitude; the biomass increased with altitude below 1600 m a.s.l., and decreased above 1600 m a.s.l. The community structure showed that glacier, and that glacier. The altitudinal distribution of snow algae is discussed in terms of the physical and chemical condition of the glacier surface, and is compared with that on a Himalayan glacier. A larger biomass in the snow area on the Alaska glacier than that of the Himalayan glacier is likely due to less frequent snow cover in summer in Alaska. Small amounts of filamentous cyanobacteria on the Alaska glacier may allow washouts of unicellular green algae by running melt water and may cause a different pattern of altitudinal distribution of algal biomass on the ice area from the Himalayan glacier.

Takeuchi, Nozomu

2001-12-01

341

21st-century evolution of Greenland outlet glacier velocities.  

PubMed

Earlier observations on several of Greenland's outlet glaciers, starting near the turn of the 21st century, indicated rapid (annual-scale) and large (>100%) increases in glacier velocity. Combining data from several satellites, we produce a decade-long (2000 to 2010) record documenting the ongoing velocity evolution of nearly all (200+) of Greenland's major outlet glaciers, revealing complex spatial and temporal patterns. Changes on fast-flow marine-terminating glaciers contrast with steady velocities on ice-shelf-terminating glaciers and slow speeds on land-terminating glaciers. Regionally, glaciers in the northwest accelerated steadily, with more variability in the southeast and relatively steady flow elsewhere. Intraregional variability shows a complex response to regional and local forcing. Observed acceleration indicates that sea level rise from Greenland may fall well below proposed upper bounds. PMID:22556249

Moon, T; Joughin, I; Smith, B; Howat, I

2012-05-01

342

SAR investigations of glaciers in northwestern North America  

NASA Technical Reports Server (NTRS)

The objective of this project was to investigate the utility of satellite synthetic aperture radar (SAR) imagery for measurement of geophysical parameters on Alaskan glaciers relevant to their mass balance and dynamics, including: (1) the positions of firn lines (late-summer snow lines); (2) surface velocities on fast-flowing (surging) glaciers, and also on slower steady-flow glaciers; and (3) the positions and changes in the positions of glacier termini. Preliminary studies of topography and glacier surface velocity with SAR interferometry have also been carried out. This project was motivated by the relationships of multi-year to decadal changes in glacier geometry to changing climate, and the probable significant contribution of Alaskan glaciers to rising sea level.

Lingle, Craig S.; Harrison, William D.

1995-01-01

343

Estimation the Dongkemadi Glacier Thickness Change by ALOS/PALSAR  

NASA Astrophysics Data System (ADS)

This paper presents a novel method to monitor the thickness changes of mountain glacier based on the deformation extracted by differential interferometric synthetic aperture radar (DInSAR) interferograms measurements of the glacier's surface. To estimate changes in surface elevation through time, we make use of differential phase and get the deformation of the glacier surface in the line of sight (LOS). The method exploits the one component of displacement along the LOS of radar beam for deriving the glacier thickness changes and uses these components to calculate thickness changes within glacier polygons. Using this method, we can monitor the thickness changes in cm-level accuracy. In order to demonstrate this method a practical example, the monitoring thickness changes of the Dongkemadi Glacier in Tibet Plateau of China, is given. The performance of this method is validated by GPS survey data. The result obtained with one DInSAR pair covering the Dongkemadi Glacier in the cold season.

Zhou, Jianmin; Li, Zhen; Tang, Zhihua; Tian, Bangsen; Chen, Quan; Huang, Lei; Liu, Jiuli

2014-03-01

344

Assessing streamflow sensitivity to variations in glacier mass balance  

USGS Publications Warehouse

Quantifying the impacts of changing glacier geometries (annual balance) on glacier runoff is essential for predicting future changes in streamflow in glacierized basins. However, determining the role that this component plays in total glacier runoff (Definition 5) requires consistent measurements of seasonal (or shorter period) mass balances, measurements of precipitation at multiple locations within a basin, and streamflow measurements in close proximity to a glaciers terminus. Practical and logistical challenges associated with assembling such data sets typically preclude such partitioning. As a result, most analyses of the relationship between annual mass balance and streamflow rely on some component of model output to compute glacier runoff (e.g. Huss et al. 2008; Kaser et al. 2010). Ultimately, developing an understanding of how total gl

O'Neel, Shad; Hood, Eran; Arendt, Anthony; Sass, Louis

2014-01-01

345

Area and volume changes from Greenland's longest-observed local glacier, Mittivakkat Gletscher, and surrounding glaciers  

NASA Astrophysics Data System (ADS)

Glaciers and ice caps are indicators of ongoing climate changes. Warming in the Arctic during the past several decades has caused local glaciers and ice caps to thin and retreat. Few mass-balance observations are available in Greenland to quantify area and volume losses and determine the extent to which these glaciers and ice caps are out of equilibrium with present-day climate. Here, we present mass balance records since 1995 and volume observations for the Mittivakkat Gletscher (17.6 km2; 6541 N, 3748 W), Southeast Greenland: the only local glacier in Greenland for which there exists long-term observations of both surface mass balance and glacier front fluctuations. Front observations were first made in 1931, taken by the British Arctic Air Route Expedition, 1930-1931, indicating continuous glacier recession since 1931 of about 1300 meters. Since 1995, mean values of observed net balance was -0.97 m w.e. The measurements show that 14 out of 16 balance years have a negative balance, and two balance years have a slightly positive balance. The cumulative mass balance since 1995 is -15.0 m w.e., corresponding to a volume loss of about 13% of the total glacier ice volume determined in 1994. Also, the Mittivakkat Gletscher (26.3 km2 in 2011) area extent has diminished about 22% since 1986 - close to the mean area exposure of 2724% for glaciers and ice caps in Southeast Greenland. Since 1986, five GIC melted away in the Ammassalik area, and one would therefore expect that GIC might melt substantially within the 21st century under ongoing climate warming.

Mernild, S. H.; Knudsen, N. T.; Yde, J. C.

2012-04-01

346

Coseismic-initiated calving at a freshwater-terminating glacier: Tasman Glacier, New Zealand  

NASA Astrophysics Data System (ADS)

Glacier retreat resulting from iceberg calving represents one of the major controls on ice loss from water-terminating glaciers (ice sheets, tidewater and freshwater glaciers) globally. However, the impact that calving has on the transfer of mass between the cryosphere and hydrosphere is still heavily debated, and the physical mechanisms behind calving remain poorly understood. Hitherto, the initiation of calving events has largely been attributed to underlying glaciological mechanisms (including fracturing of ice due to high longitudinal stress gradients) and changes in the proglacial water-body characteristics. We present evidence for a large-magnitude calving event following high magnitude (>Mw 6) earthquakes as a potentially important triggering mechanism of calving in tectonically-active areas. We describe the response of Tasman Glacier, New Zealand, a freshwater-terminating glacier undergoing accelerated calving retreat, to the Mw 6.3, 5.7 and 4.5 Christchurch 22 February 2011 earthquakes and the subsequent calving event. Time-series analysis of timed video and photographic records of the glacier terminus immediately pre-, co- and post- the 22 February earthquakes demonstrates that the large calving event on the 22 February 2011 occurred in direct response to a resonance effect caused by shear (S-) waves oscillating the terminus at the ice-water interface. We suggest that, in this instance, the magnitude of calving was amplified because Tasman Glacier had reached a critical threshold for buoyancy-induced calving in relation to perturbations in lake level. Prior to this event, small- to intermediate magnitude calving, leading to terminus retreat, had been dominated by thermo-erosional notching at the waterline, destabilising the subaerial ice cliff. Indeed, recent (post-2006) large calving events have primarily been driven by torque-induced, buoyancy-driven calving. Hence, in tectonically-active areas, coseismic-initiated calving can have an episodic, but strong control on retreat, potentially destabilising a glacier system and leading to accelerated recession, accentuating climate-forced mass balance changes.

Dykes, R. C.; Lube, G.; Brook, M. S.

2012-04-01

347

Glacier dynamics at Helheim and Kangerdlugssuaq glaciers, southeast Greenland, since the Little Ice Age  

NASA Astrophysics Data System (ADS)

Observations over the past decade show significant ice loss associated with the speed-up of glaciers in southeast Greenland from 2003, followed by a deceleration from 2006. These short-term, episodic, dynamic perturbations have a major impact on the mass balance on the decadal scale. To improve the projection of future sea level rise, a long-term data record that reveals the mass balance beyond such episodic events is required. Here, we extend the observational record of marginal thinning of Helheim and Kangerdlugssuaq glaciers from 10 to more than 80 years. We show that, although the frontal portion of Helheim Glacier thinned by more than 100 m between 2003 and 2006, it thickened by more than 50 m during the previous two decades. In contrast, Kangerdlugssuaq Glacier underwent minor thinning of 40-50 m from 1981 to 1998 and major thinning of more than 100 m after 2003. Extending the record back to the end of the Little Ice Age (prior to 1930) shows no thinning of Helheim Glacier from its maximum extent during the Little Ice Age to 1981, while Kangerdlugssuaq Glacier underwent substantial thinning of 230 to 265 m. Comparison of sub-surface water temperature anomalies and variations in air temperature to records of thickness and velocity change suggest that both glaciers are highly sensitive to short-term atmospheric and ocean forcing, and respond very quickly to small fluctuations. On century timescales, however, multiple external parameters (e.g. outlet glacier shape) may dominate the mass change. These findings suggest that special care must be taken in the projection of future dynamic ice loss.

Khan, S. A.; Kjeldsen, K. K.; Kjr, K. H.; Bevan, S.; Luckman, A.; Aschwanden, A.; Bjrk, A. A.; Korsgaard, N. J.; Box, J. E.; van den Broeke, M.; van Dam, T. M.; Fitzner, A.

2014-08-01

348

Glaciers along proposed routes extending the Copper River Highway, Alaska  

USGS Publications Warehouse

Three inland highway routes are being considered by the Alaska Department of Transportation and Public Facilities to connect the community of Cordova in southcentral Alaska to a statewide road system. The routes use part of a Copper River and Northwest Railway alignment along the Copper River through mountainous terrain having numerous glaciers. An advance of any of several glaciers could block and destroy the roadway, whereas retreating glaciers expose large quantities of unconsolidated, unvegetated, and commonly ice-rich sediments. The purpose of this study was to map historical locations of glacier termini near these routes and to describe hazards associated with glaciers and seasonal snow. Historical and recent locations of glacier termini along the proposed Copper River Highway routes were determined by reviewing reports and maps and by interpreting aerial photographs. The termini of Childs, Grinnell, Tasnuna, and Woodworth Glaciers were 1 mile or less from a proposed route in the most recently available aerial photography (1978-91); the termini of Allen, Heney, and Schwan Glaciers were 1.5 miles or less from a proposed route. In general, since 1911, most glaciers have slowly retreated, but many glaciers have had occasional advances. Deserted Glacier and one of its tributary glaciers have surge-type medial moraines, indicating potential rapid advances. The terminus of Deserted Glacier was about 2.1 miles from a proposed route in 1978, but showed no evidence of surging. Snow and rock avalanches and snowdrifts are common along the proposed routes and will periodically obstruct the roadway. Floods from ice-dammed lakes also pose a threat. For example, Van Cleve Lake, adjacent to Miles Glacier, is as large as 4.4 square miles and empties about every 6 years. Floods from drainages of Van Cleve Lake have caused the Copper River to rise on the order of 20 feet at Million Dollar Bridge.

Glass, R.L.

1996-01-01

349

Changes in the Surface Area of Glaciers in Northern Eurasia  

NASA Astrophysics Data System (ADS)

Glaciers are widely recognized as key indicators of climate change. Recent evidence suggests an acceleration of glacier mass loss in several key mountain regions. Glacier recession implies the landscape changes in the glacial zone, origin of new lakes and activation of natural disaster processes, catastrophic mudflows, ice avalanches, outburst floods, and etc. The presence of glaciers in itself threats to human life, economic activity and growing infrastructure. Economical and recreational human activity in mountain regions requires relevant information on snow and ice objects. Absence or inadequacy of such information results in financial and human losses. A more comprehensive evaluation of glacier changes is imperative to assess ice contributions to global sea level rise and the future of water resources from glacial basins. One of the urgent steps is a full inventory of all ice bodies, their volume and changes The first estimation of glaciers state and glaciers distribution in the big part of Northern Eurasia has been done in the USSR Glacier Inventory published in 1966 -1980 as a part of IHD activity. The Inventory is based on topographic maps and air photos and reflects the status of the glaciers in 1957-1970y. There is information about 23796 glaciers with area of 78222.3 km2 in the Inventory. It covers 23 glacier systems on Northern Eurasia. In the 80th the USSR Glacier Inventory has been transformed in the digital form as a part of the World Glacier Inventory. Recent satellite data provide a unique opportunity to look again at these glaciers and to evaluate changes in glacier extent for the second part of XX century. In the paper we report about 15 000 glaciers outlines for Caucasus, Pamir, Tien-Shan, Altai, Syntar-Khayata, Cherskogo Range, Kamchatka and Russian Arctic which have been derived from ASTER and Landsat imagery and could be used for glacier changes evaluation. The results show that glaciers are retreating in all these regions. There is, however, a rather large variability in degree of reduction very much depending on special local conditions and this was particularly notable with regard to smaller glaciers.

Khromova, T.; Nosenko, G.

2012-12-01

350

Hasty retreat of glaciers in the Palena province of Chile  

NASA Astrophysics Data System (ADS)

Mapping glacier extent from optical satellite data has become a most efficient tool to create or update glacier inventories and determine glacier changes over time. A most valuable archive in this regard is the nearly 30-year time series of Landsat Thematic Mapper (TM) data that is freely available (already orthorectified) for most regions in the world from the USGS. One region with a most dramatic glacier shrinkage and a missing systematic assessment of changes, is the Palena province in Chile, south of Puerto Montt. A major bottleneck for accurate determination of glacier changes in this region is related to the huge amounts of snow falling in this very maritime region, hiding the perimeter of glaciers throughout the year. Consequently, we found only three years with Landsat scenes that can be used to map glacier extent through time. We here present the results of a glacier change analysis from six Landsat scenes (path-rows 232-89/90) acquired in 1985, 2000 and 2011 covering the Palena district in Chile. Clean glacier ice was mapped automatically with a standard technique (TM3/TM band ratio) and manual editing was applied to remove wrongly classified lakes and to add debris-covered glacier parts. The digital elevation model (DEM) from SRTM was used to derive drainage divides, determine glacier specific topographic parameters, and analyse the area changes in regard to topography. The scene from 2000 has the best snow conditions and was used to eliminate seasonal snow in the other two scenes by digital combination of the binary glacier masks. The observed changes show a huge spatial variability with a strong dependence on elevation and glacier hypsometry. While small mountain glaciers at high elevations and steep slopes show virtually no change over the 26-year period, ice at low elevations from large valley glaciers shows a dramatic decline (area and thickness loss). Some glaciers retreated more than 3 km over this time period or even disappeared completely. Typically, these glaciers lost contact to the accumulation areas of tributaries and now consist of an ablation area only. Furthermore, numerous pro-glacial lakes formed or expanded rapidly, increasing the local hazard potential. On the other hand, some glaciers located on or near to (still active) volcanoes have also advanced in the same time period. Observed trends in temperature (decreasing) are in contrast to the observed strong glacier shrinkage.

Paul, F.; Mlg, N.; Bolch, T.

2013-12-01

351

Conditions for thrust faulting in a glacier  

Microsoft Academic Search

Dipping, arcuate bands of debris-rich ice outcropping near the margins of glaciers are often interpreted as thrust faults, assumed to originate in zones of longitudinal compression. Identification of thrusts is typically based either on the geometry and sedimentology of the debris bands or on the crystal fabric of surrounding ice, but the physical processes necessary to generate thrusts are rarely

Peter L. Moore; Neal R. Iverson; Denis Cohen

2010-01-01

352

Glacier Surge After Ice Shelf Collapse  

Microsoft Academic Search

The possibility that the West Antarctic Ice Sheet will collapse as a consequence of ice shelf disintegration has been debated for many years. This matter is of concern because such an event would imply a sudden increase in sea level. Evidence is presented here showing drastic dynamic perturbations on former tributary glaciers that fed sections of the Larsen Ice Shelf

Hernn De Angelis; Pedro Skvarca

2003-01-01

353

A Facies Model for Temperate Continental Glaciers.  

ERIC Educational Resources Information Center

Discusses the presence and dynamics of continental glaciers in the domination of the physical processes of erosion and deposition in the mid-latitudes during the Pleistocene period. Describes the use of a sedimentary facies model as a guide to recognizing ancient temperate continental glacial deposits. (TW)

Ashley, Gail Mowry

1987-01-01

354

Panoramic of Glaciers in the Caucasus Moutains  

USGS Multimedia Gallery

Panoramic photographic mosaic of several glaciers on the northern slope of Gora Elbrus, a volcanic massif in the Central Caucasus Mountains. The photographic survey was done by N. Nikulin in 1957 during the International Geophysical Year. Photograph courtesy of V.M. Kotlyakov, Russian Academy of Sci...

355

Rapid ice discharge from southeast Greenland glaciers  

E-print Network

[1] Interferometric synthetic-aperture radar (InSAR) observations of southeast Greenland glaciers acquired by the Earth Remote Sensing Satellites (ERS-1/2) in 1996 were combined with ice sounding radar data collected in the late 1990s to estimate a...

Rignot, E.; Braaten, David A.; Gogineni, S. Prasad; Krabill, W. B.; McConnell, J. R.

2004-03-25

356

The Bay in Place of a Glacier.  

ERIC Educational Resources Information Center

The cultural resource specialist at Glacier Bay National Park (Alaska) explains the collaborative efforts of park staff and the Hoonah Tlingit to overcome language and cultural barriers in documenting park place names and clan oral history and traditions. The new park-community relationship, which follows decades of conflict, includes training

Howell, Wayne

1997-01-01

357

Fast Recession of a West Antarctic Glacier  

NASA Technical Reports Server (NTRS)

Satellite radar interferometry observations of Pine Island Glacier, in West Antarctica, reveal that the hinge-line position of this major ice stream retreated 1.2+/-0.2 km per year between 1992 and 1996, which in turn implies ice thinning at 3.5+/-0.6m ice per year.

Rignot, E. J.

1998-01-01

358

The History of the Glacier Facies Concept  

Microsoft Academic Search

The concept of glacier facies developed as a result of physical measurements made in Greenland on repeated traverses that went inland from the west coast at two latitudes (77 N and 70 N) and north to south along the crest of the ice sheet. Snow pits and shallow cores showed discontinuities in physical characteristics that defined the facies boundaries. Some

C. S. Benson

2001-01-01

359

Geology Fieldnotes: Glacier National Park, Montana  

NSDL National Science Digital Library

Glaciers have played an important role in shaping this park, which is part of the Rocky Mountain chain and shares a border with Canada's Waterton Lakes National Park. Information on this site includes park geology, visitor information, photographs, and links to other resources.

360

EVALUATION OF POLARIMETRIC CONFIGURATIONS FOR GLACIER CLASSIFICATION  

Microsoft Academic Search

We investigate the classification information contained in the different polarisation channels from a fully polari- metric scene of an arctic glacier. Specifically, we com- pare classifications from the full quadruple polarisation data; dual polarisation modes; and each single polari- sation channel. The classifications are performed with both the standard Wishart classifier and a non-Gaussian based K-Wishart classifier. Post classification class

Anthony P. Doulgeris; Stian N. Anfinsen; Yngvar Larsen; Kirsty Langley; Torbjrn Eltoft

2009-01-01

361

Glacier Change Investigation for Early Elementary Students  

NASA Astrophysics Data System (ADS)

Few opportunities exist for early elementary students to do inquiry or guided inquiry into topics dealing with climate change and glaciers. "Flubber" offers a simulation for the movement of glacial ice. It is inexpensive to make, stores well, and can be re-used. Students of all ages enjoy watching, measuring, and thinking about flubber and what it represents. As the interest in ice sheets continues to build, activities that both help to illustrate how glaciers move and provide a launch pad for student-driven investigations need to be available to teachers. With support from the National Science Foundation's Science and Technology Center for the Remote Sensing of Ice Sheets (CReSIS), a set of activities has been developed to provide opportunities for early elementary students to develop inquiry skills within the standards for early elementary grades bands in the National Science Education Standards. Lesson plans, instructions for making and using "Flubber", student worksheets, teacher guides with glacier and climate change information, and a chart of the National Science Education Standards applicable to the activities are available to elementary teachers wishing to introduce their students to glaciers and climate change.

Hintz, R. S.; Landis, C.

2008-12-01

362

Conditions for thrust faulting in a glacier  

NASA Astrophysics Data System (ADS)

Dipping, arcuate bands of debris-rich ice outcropping near the margins of glaciers are often interpreted as thrust faults, assumed to originate in zones of longitudinal compression. Identification of thrusts is typically based either on the geometry and sedimentology of the debris bands or on the crystal fabric of surrounding ice, but the physical processes necessary to generate thrusts are rarely evaluated. Herein, we combine a numerical model of compressive ice flow near a glacier margin with theoretical stress and strain rate criteria for ice fracture and stress criteria for frictional slip to determine the conditions necessary for thrust faulting in glaciers. This model is applied to two different glaciological settings where longitudinal compression has been documented: (1) the transition between warm-based and cold-based ice near the terminus of Storglaciren, Sweden, and (2) the downglacier extent of the 1983 surge front of Variegated Glacier where surging ice encountered stagnant ice. Simulations representing the margin of Storglaciren indicate that peak compressive strain rates are six orders of magnitude too small to induce fracture, whereas at Variegated Glacier, strain rates were an order of magnitude too small for compressive fracture. In both groups of simulations, preexisting fractures governed by Coulomb friction are susceptible to slip if they span the ice thickness, are oriented close to the optimal fracture angle, and, in the case of Storglaciren, are subject to water pressures that are a large fraction of ice overburden pressure. Variations about the optimal fracture orientation, low or zero water pressure, high sliding friction coefficient, and limited vertical or lateral fracture extent each tend to suppress thrusting.

Moore, Peter L.; Iverson, Neal R.; Cohen, Denis

2010-06-01

363

New Zealand glacier response to climate change of the past 2 decades  

Microsoft Academic Search

Oblique aerial photography of 111 glaciers during the past 2 decades has recorded a reversal of the past century glacier-recession trend. Cirque glaciers show little response to the recent mass balance increase; mountain glaciers show visible advances. Some valley glaciers have advanced, some have thickened in the upper trunk, and the larger ones and those with proglacial lakes continue to

T. J Chinn

1999-01-01

364

Alaska Park Science, Volume 12, Issue 2 Status and Trends of Alaska National Park Glaciers  

E-print Network

Glaciers: What Do They Tell Us About Climate Change? Michael G. Loso, Anthony Arendt, Chris Larsen, Nate with the fact that the state's many glaciers are changing. Many glaciers are shrinking, and "retreat" of the glacier terminus is usually the most obvious manifestation of that change. But while some glaciers (like

Loso, Michael G.

365

Glacier Guide for Departments, v. 3.3 Page 1 ONLINE NONRESIDENT ALIEN TAX COMPLIANCE SYSTEM  

E-print Network

Glacier Guide for Departments, v. 3.3 Page 1 GLACIER ONLINE NONRESIDENT ALIEN TAX COMPLIANCE SYSTEM Glacier Guide for Departments All Glacier-related documents & forms are available in electronic format. Please email awinterton@ucsd.edu to request copies. · Glacier Information Form (Interactive pdf

Jun, Suckjoon

366

52 glaciers and one lake: how to reconstruct past regional glacier variability  

NASA Astrophysics Data System (ADS)

Sediment records from distal glacier-fed lakes have been used in numerous reconstructions of past glacier activity, where the basic assumption is that the amount of minerogenic material deposited in the lake is directly proportional to the amount of upstream glacier erosion. However, the minerogenic component of the sediments in a distal glacier-fed lake is commonly derived from several different sources, not only subglacial erosion. Furthermore, glacier reconstructions tend to focus on individual mountain glaciers, which due to local effects might not always reflect regional scale glacier variability. Presently, certain high-resolution analysis techniques allow for fast multi-proxy analyses of sediment cores, which improve the basis for inferring the provenance of lake sediments; however, the only way of actually testing such inferences is to identify the different sediment sources in the adjacent catchment and characterize them using the same proxy measurements as in the lake core. Multi-proxy sedimentary fingerprinting techniques are labor-intensive, however, and proxies such as bulk geochemistry may prove of little use in differentiating between source areas if the bedrock lithology is uniform across the catchment. Here we present a simple method based on environmental magnetism that allow for tracking lake sediments to their sources in catchments where the bedrock lithology is uniform. Unlike ferro- and ferrimagnetic minerals, the magnetic susceptibility of paramagnetic minerals is inversely proportional to temperature. Thus, by measuring the bulk magnetic susceptibility (chi-Bulk) of a sediment sample both at room temperature (293K) and after freezing in liquid nitrogen (77K), the relative contribution from paramagnetic minerals to the total chi-Bulk can be inferred from the ratio of chi-Bulk77K over chi-Bulk293K. Theoretically, a ratio of 3.8 will indicate a purely paramagnetic sample, whereas progressively lower values reflect an increasing contribution from ferro- or ferrimagnetic minerals. We found that in the catchment of Nerfloen, a distal lake draining a large (440 km2) catchment in western Norway that contains 52 separate glaciers, there was a systematic decrease in the chi-Bulk77K/chi-Bulk293K-ratio with increasing altitude and proximity to the glaciers. We have not studied the magnetic mineralogy of our samples in detail, but infer from our data that the relative amount of paramagnetic minerals increase as soil formation progresses, thereby creating the contrasting ratios between samples collected at different altitudes. In the lake core we observe rapid shifts between sedimentary regimes dominated by high- and low-altitude source areas, which can best be explained by regional-scale growth and decay of mountain glaciers in the lake catchment.

Vasskog, Kristian; Paasche, yvind; Nesje, Atle; Boyle, John F.; Birks, H. John B.

2014-05-01

367

Harnessing Wind  

NSDL National Science Digital Library

Students are introduced to the ways that engineers study and harness the wind. They learn about the different kinds of winds and how to measure wind direction. In addition, they learn how air pressure creates winds and how engineers design and test wind turbines to harness renewable wind energy.

2014-09-18

368

A metagenomic snapshot of taxonomic and functional diversity in an alpine glacier cryoconite ecosystem  

NASA Astrophysics Data System (ADS)

Cryoconite is a microbe-mineral aggregate which darkens the ice surface of glaciers. Microbial process and marker gene PCR-dependent measurements reveal active and diverse cryoconite microbial communities on polar glaciers. Here, we provide the first report of a cryoconite metagenome and culture-independent study of alpine cryoconite microbial diversity. We assembled 1.2 Gbp of metagenomic DNA sequenced using an Illumina HiScanSQ from cryoconite holes across the ablation zone of Rotmoosferner in the Austrian Alps. The metagenome revealed a bacterially-dominated community, with Proteobacteria (62% of bacterial-assigned contigs) and Bacteroidetes (14%) considerably more abundant than Cyanobacteria (2.5%). Streptophyte DNA dominated the eukaryotic metagenome. Functional genes linked to N, Fe, S and P cycling illustrated an acquisitive trend and a nitrogen cycle based upon efficient ammonia recycling. A comparison of 32 metagenome datasets revealed a similarity in functional profiles between the cryoconite and metagenomes characterized from other cold microbe-mineral aggregates. Overall, the metagenomic snapshot reveals the cryoconite ecosystem of this alpine glacier as dependent on scavenging carbon and nutrients from allochthonous sources, in particular mosses transported by wind from ice-marginal habitats, consistent with net heterotrophy indicated by productivity measurements. A transition from singular snapshots of cryoconite metagenomes to comparative analyses is advocated.

Edwards, Arwyn; Pachebat, Justin A.; Swain, Martin; Hegarty, Matt; Hodson, Andrew J.; Irvine-Fynn, Tristram D. L.; Rassner, Sara M. E.; Sattler, Birgit

2013-09-01

369

Franz Josef and Fox Glaciers, New Zealand: Historic length records  

NASA Astrophysics Data System (ADS)

Compilation of modern and historical length change records for Franz Josef and Fox Glaciers demonstrates that these glaciers have lost ~ 3 km in length and at least 3-4 km2 in area since the 1800s, with the greatest overall loss occurring between 1934 and 1983. Within this dramatic and ongoing retreat, both glaciers have experienced periods of re-advance. The record from Franz Josef Glacier is the most detailed, and shows major advances from 1946 to 1951 (340 m), 1965-1967 (400 m), 1983-1999 (1420 m) and 2004-2008 (280 m). At Fox Glacier the record is similar, with advances recorded during 1964-1968 (60 m), 1985-1999 (710 m) and 2004-2008 (290 m). Apart from the latest advance event, the magnitude of advance has been greater at Franz Josef Glacier, suggesting a higher length sensitivity. Analysis of the relationship between glacier length and a reconstructed annual equilibrium line altitude (ELA) record shows that the glaciers react very quickly to ELA variations - with the greatest correlation at 3-4 years' lag. The present (2014) retreat is the fastest retreat in the records of both glaciers. While decadal length fluctuations have been linked to hemispheric ocean-atmosphere variability, the overall reduction in length is a clear sign of twentieth century warming. However, documenting glacier length changes can be challenging; especially when increased surface debris-cover makes identification of the true terminus a convoluted process.

Purdie, Heather; Anderson, Brian; Chinn, Trevor; Owens, Ian; Mackintosh, Andrew; Lawson, Wendy

2014-10-01

370

What glaciers are telling us about Earth's changing climate  

NASA Astrophysics Data System (ADS)

A glacier monitoring system has been developed to systematically observe and document changes in the size and extent of a representative selection of the world's 160 000 mountain glaciers (entitled the PTAAGMB Project). Its purpose is to assess the impact of climate change on human societies by applying an established relationship between glacier ablation and global temperatures. Two sub-systems were developed to accomplish this goal: (1) a mass balance model that produces daily and annual glacier balances using routine meteorological observations, (2) a program that uses Google Maps to display satellite images of glaciers and the graphical results produced by the glacier balance model. The recently developed PTAA glacier balance model is described and applied to eight glaciers to produce detailed mass balance reports. Comparing annual balances produced by the model to traditional manual measurements for 50-60 years yields R2 values of 0.50-0.60. The model also reveals an unusual but statistically significant relationship between the average ablation of Wrangell Range glaciers and global temperatures that have been derived from temperature data at 7000 stations in the Northern Hemisphere. This glacier ablation/global temperature relationship provides the means to use worldwide ablation results to anticipate problems caused by climate change.

Tangborn, W.; Mosteller, M.

2014-07-01

371

Assessing streamflow sensitivity to variations in glacier mass balance  

NASA Astrophysics Data System (ADS)

We examine long-term streamflow and mass balance data from two Alaskan glaciers located in climatically distinct basins: Gulkana Glacier, a continental glacier located in the Alaska Range, and Wolverine Glacier, a maritime glacier located in the Kenai Mountains. Both glaciers lost mass, primarily as a result of summer warming, and both basins exhibit increasing streamflow over the 1966-2011 study interval. We estimated total glacier runoff via summer mass balance, and separated the fraction related to annual mass imbalances. In both climates, the fraction of streamflow related to annual mass balance averages less than 20%, substantially smaller than the fraction related to total summer mass loss (>50%), which occurs even in years of glacier growth. The streamflow fraction related to changes in annual mass balance has increased only in the continental environment. In the maritime climate, where deep winter snowpacks and frequent rain events drive consistently high runoff, the magnitude of this streamflow fraction is small and highly variable, precluding detection of any existing trend. Changes in streamflow related to annual balance are often masked by interannual variability of maritime glacier mass balance, such that predicted scenarios of continued glacier recession are more likely to impact the quality and timing of runoff than the total basin water yield.

Oneel, S.; Hood, E. W.; Arendt, A. A.; Sass, L. C.; March, R. S.

2013-12-01

372

Modelling glacier change in the Everest region, Nepal Himalaya  

NASA Astrophysics Data System (ADS)

In this study, we apply a glacier mass balance and ice redistribution model to simulate historical and future glacier change in the Everest region of Nepal. High-resolution temperature and precipitation fields derived from gridded APHRODITE data, and validated against independent station observations from the EVK2CNR network, are used to drive the historical model from 1961 to 2007. The model is calibrated against geodetically derived estimates of net glacier mass change from 1992 to 2008, termini position of four large glaciers at the end of the calibration period, average velocities observed on selected debris-covered glaciers, and total glacierized area. We integrate field-based observations of glacier mass balance and ice thickness with remotely-sensed observations of decadal glacier change to validate the model. Between 1961 and 2007, the mean modelled volume change over the Dudh Kosi basin is -6.4 1.5 km3, a decrease of 15.6% from the original estimated ice volume in 1961. Modelled glacier area change between 1961 and 2007 is -101.0 11.4 km2, a decrease of approximately 20% from the initial extent. Scenarios of future climate change, based on CMIP5 RCP4.5 and RCP8.5 end members, suggest that glaciers in the Everest region will continue to lose mass through the 21st century. Glaciers in the basin are concentrated between 5000 and 6000 m of elevation, and are thus expected to be sensitive to changes in temperature and equilibrium line altitude (ELA). Glacier volume reductions between -35 to -62% are possible by 2050, and sustained temperature increases to 2100 may result in total glacier volume losses of between -73 and -96%.

Shea, J. M.; Immerzeel, W. W.; Wagnon, P.; Vincent, C.; Bajracharya, S.

2014-10-01

373

Characteristics of the turbulent flow in the surface layer of a Tropical Glacier  

NASA Astrophysics Data System (ADS)

Energy balance studies on glaciers mostly use aerodynamic profile methods, assuming hypotheses of Monin-Obukhov similarity theory are valid, in order to compute sensible and latent turbulent heat fluxes. Nevertheless, various turbulence measurements have shown that the turbulent flow in the surface layer is not in equilibrium and stationnary within mountainous rough topography. Few of these studies focus on tropical glaciers, and little is known about the dynamics of the surface layer in these environnments. We thus have deployed an extensive micro-meteorological experiment within the atmospheric surface layer over the ablation zone of the tropical Zongo glacier, Bolivia, during the dry season from July to August, 2007. Stations were installed around 5050 m a.s.l. They included two complete eddy covariance systems at a 2-m mean level and a 6-m mast measuring the mean profiles of air temperature and of wind speed. Data is used to characterize the conditions in the surface layer. Weakly stable conditions prevailed in the first meters above the ice or snow surface. With weak large scale forcing, a katabatic downslope flow with a wind maximum at about 2-m height usually appeared in the middle of the afternoon and maintained itself during most of the night. Profile data is fitted to derive roughness lenghts and characterize their evolution. The study of statistical moments of high frequency wind speed and temperature data shows that the wind regime was highly gusty and irregular. Stationary conditions were rarely encountered. Characteristics and structure of the turbulent flow were studied using spectral analysis. It shows that the observed turbulence cannot be generated only by local shear and that low frequency perturbations interact with the surface layer turbulence and lead to divergence from the classical Kansas surface layer curves. We compare the spectra for different typical meteorological conditions and katabatic wind maximum heights. It gives us insights on the extent of these perturbations regarding to the conditions. We test the influence of the nearness of the wind maximum on eddy covariance measurements and flux divergence in the few meters above the surface.

Litt, Maxime; Sicart, Jean-Emmanuel

2013-04-01

374

Controlling mechanisms of Thwaites Glacier, West Antarctica  

NASA Astrophysics Data System (ADS)

Ice shelves play a major role in the stability of fast flowing ice streams in Antarctica, by exerting buttressing on inland ice and controlling the discharge of ice into the ocean. However, the mechanisms at work remain poorly understood and interactions between floating and grounded ice need to be better characterized in order to estimate the impact of climate change on the ice sheets. Thwaites glacier, in West Antarctica, features a small and heavily fractured ice shelf that provides limited back stress pressure on inland ice but is pinned on the eastern part on a prominent ridge. Thwaites glacier has maintained a consistently high velocity and negative mass balance for at least 20 years. Recent observations show a widening of its fast flowing area as well as a sustained acceleration since 2006 and a rapid retreat of its grounding line in the center of the glacier. The objective of this work is to characterize the dynamic response of Thwaites glacier to changes in its floating tongue on decadal to centennial time scales. To achieve this objective, we rely on high resolution ice flow modeling and grounding line dynamics using the Ice Sheet System Model (ISSM). We will focus on the complex interplay between the main floating tongue of Thwaites Glacier and its eastern, slow moving ice shelf, which is pinned down by an ice rumple. The speed of the eastern ice shelf is strongly affected by the coupling with the main floating ice tongue, which results in significant fluctuations in speed of the eastern ice shelf the formation of ice shelf cracks at the grounding line during acceleration phases. Our results show that ice rigidity at the junction between the eastern and western part of the shelf controls the dynamic regime of the ice shelf and suggest that Thwaites Glacier is likely to undergo substantial changes in the coming decades. This work was performed at the California Institute of Technology's Jet Propulsion Laboratory and the University of California Irvine under a contract with the National Aeronautics and Space Administration, Cryospheric Sciences and Modeling, Analysis and Prediction Programs

Seroussi, H. L.; Morlighem, M.; Rignot, E. J.; Larour, E. Y.; Mouginot, J.; Khazendar, A.

2013-12-01

375

Present and future contribution of glacier storage change to runoff from macroscale drainage basins in Europe  

Microsoft Academic Search

Glaciers make a significant runoff contribution in macroscale drainage basinsThe impact of glacial melt water is recognizable with very small glacierizationThe retreat of alpine glaciers plays an important role in future water shortage

Matthias Huss

2011-01-01

376

For Immediate Release --Monday, March 18, 2013 From Glaciers to drinking water: University of Lethbridge  

E-print Network

For Immediate Release -- Monday, March 18, 2013 From Glaciers Water Day, Friday, Mar. 22 - Where have all the glaciers's future. ++++++++++ Where have all the glaciers gone? Dr. Hester Jiskoot studies

Seldin, Jonathan P.

377

Quantitative estimates of velocity sensitivity to surface melt variations at a large Greenland outlet glacier  

E-print Network

The flow speed of Greenland outlet glaciers is governed by several factors, the relative importance of which is poorly understood. The delivery of surface-generated meltwater to the bed of alpine glaciers has been shown to influence glacier flow...

Anderson, M.L.; Nettles, M.; Larsen, T.B.; Hamilton, Gordon S.; Stearns, Leigh

2011-09-01

378

Glacier Meltwater Contributions and Glaciometeorological Regime of the Illecillewaet River Basin, British Columbia,  

E-print Network

Glacier Meltwater Contributions and Glaciometeorological Regime of the Illecillewaet River Basin This study characterizes the meteorological parameters influencing glacier runoff and quantifies recent glacier contributions to streamflow in the Illecillewaet River basin, British Columbia. The Illecillewaet

Smith, Dan

379

Sudden increase in tidal response linked to calving and acceleration at a large Greenland outlet glacier  

E-print Network

[1] Large calving events at Greenland's largest outlet glaciers are associated with glacial earthquakes and near-instantaneous increases in glacier flow speed. At some glaciers and ice streams, flow is also modulated in a regular way by ocean tidal...

de Juan, J.; Elosegui, P.; Nettles, M.; Larsen, T.B.; Davis, J.L.; Hamilton, Gordon S.; Stearns, Leigh; Anderson, M.L.; Ekstrom, G.; Ahlstrom, A.P.; Stenseng, L.; Khan, S.A.; Forsberg, R.

2010-06-23

380

Snow glacier melt estimation in tropical Andean glaciers using artificial neural networks  

NASA Astrophysics Data System (ADS)

Snow and glacier melt (SGM) estimation plays an important role in water resources management. Although melting process can be modelled by energy balance methods, such studies require detailed data, which is rarely available. Hence, new and simpler approaches are needed for SGM estimations. The present study aims at developing an artificial neural networks (ANN) based technique for estimating the energy available for melt (EAM) and SGM rates using available and easy to obtain data such as temperature, short-wave radiation and relative humidity. Several ANN and multiple linear regression models (MLR) were developed to represent the energy fluxes and estimate the EAM. The models were trained using measured data from the Zongo glacier located in the outer tropics and validated against measured data from the Antizana glacier located in the inner tropics. It was found that ANN models provide a better generalisation when applied to other data sets. The performance of the models was improved by including Antizana data into the training set, as it was proved to provide better results than other techniques like the use of a prior logarithmic transformation. The final model was validated against measured data from the Alpine glaciers Argentire and Saint-Sorlin. Then, the models were applied for the estimation of SGM at Condoriri glacier. The estimated SGM was compared with SGM estimated by an enhanced temperature method and proved to have the same behaviour considering temperature sensibility. Moreover, the ANN models have the advantage of direct application, while the temperature method requires calibration of empirical coefficients.

Moya Quiroga, V.; Mano, A.; Asaoka, Y.; Kure, S.; Udo, K.; Mendoza, J.

2013-04-01

381

GLACIER FLUCTUATIONS IN THEALPS OVER THE LAST FOURMILLENNIA-PART 3 59 Precisely dated glacier fluctuations in theAlps over the  

E-print Network

GLACIER FLUCTUATIONS IN THEALPS OVER THE LAST FOURMILLENNIA-PART 3 59 Precisely dated glacier;?Instituteof GeologicalSciences, Universip$Ben, Ben, Sm'tzerland; WSL,Birmensdolf;Switzerland Mountain glaciers are highly glacier retreat in the European Alps is the most striking en+ronmental evidencefor currentclimaticchange

Nicolussi, Kurt

382

The new remote-sensing-derived Swiss glacier inventory  

Microsoft Academic Search

ABSTRACT. A new Swiss glacier inventory is to be compiled from satellite data for the year 2000.The study presented here describes two major tasks: (1) an accuracy assessment of different methods for glacier classificationwith LandsatThematic Mapper (TM) data and a digital elevation model,(DEM); (2) the geographical,information,system (GIS)-based methods for automatic extraction of individual glaciers from classified satellite data and the

Frank Paul; Andreas Kb; Max Maisch; Tobias Kellenberger; Wilfried Haeberli

383

A review of the modern fluctuations of tropical glaciers  

Microsoft Academic Search

The tropical climate is characterized by a homogeneous atmosphere without frontal activity, a lack of thermal seasonality, and by one to two differently pronounced precipitation seasons. Consequently, tropical climate has a characteristic impact on tropical glaciers, with glacierclimate interactions different from those of the mid- and high-latitudes.The glaciers of tropical South America, Africa and New Guinea had a general maximum

Georg Kaser

1999-01-01

384

10 000 ans de fonte des glaciers andins expliqus  

E-print Network

N° 377 Juin 2011 10 000 ans de fonte des glaciers andins expliqués Scientific news Actualidad cientifica Actualité scientifique Si la fonte des glaciers a largement été démontrée dans le monde, le cas particulier des glaciers tropi- caux n'est pas encore bien connu. Ces derniers sont principalement situés dans

385

A review of the modern fluctuations of tropical glaciers  

NASA Astrophysics Data System (ADS)

The tropical climate is characterized by a homogeneous atmosphere without frontal activity, a lack of thermal seasonality, and by one to two differently pronounced precipitation seasons. Consequently, tropical climate has a characteristic impact on tropical glaciers, with glacier-climate interactions different from those of the mid- and high-latitudes. The glaciers of tropical South America, Africa and New Guinea had a general maximum extent during the Little Ice Age (LIA) and have receded since the second half of the 19th century. Since then the fluctuations have been differently pronounced in different regions, but their general behaviour has been largely synchronous. The retreat from the LIA extent slowed on many glaciers at the beginning of the 20th century, some of them even readvanced almost to the LIA extent. The 1930s and 1940s brought a marked loss of ice masses and were followed by a moderate retreat. Around 1970 the recession generally slowed. Some glaciers even advanced. The last decade was again characterized by a pronounced glacier recession on all tropical mountains which are under observation. The modern fluctuations of tropical glaciers are also quite synchronous to those of the glaciers in the mid-latitudes. A reduction in air humidity with all the consequent changes in energy and mass balance is suggested to be a major reason for the general recession of tropical glaciers since the end of LIA. The rise in air temperature explains only part of the glacier recession. The accelerated recession since the 1980s is most probably caused by increased air temperature and increased air humidity. Nevertheless, the knowledge of tropical glaciers is still scarce compared to those of the mid and high latitudes. This contribution reviews present knowledge of the fluctuations of tropical glaciers.

Kaser, Georg

1999-10-01

386

Glacier Bay, Alaska, from the Ground, Air, and Space  

NASA Technical Reports Server (NTRS)

This tape uses a combination of video, three-dimensional computer imaging, and still photographs to provide a descriptive overview of the life-cycle and environmental effects of glaciers. An historical prospective of researchers and the contribution that they have made to the understanding of glaciers and Glacier Bay is presented. The data collected from these scientists have been documented and used by means of scientific visualization in the hope of learning how glacial activity relates to climate changes.

Hall, Dorothy K.

1997-01-01

387

Satellite Image Atlas of Glaciers of the World: North America  

NSDL National Science Digital Library

This atlas contains Landsat images, aerial photographs, selected maps, and other data, which provide a baseline look (from the mid-1970's) at glaciation in Canada, the conterminous United States, and Mexico. The Landsat false-color imagery includes ice fields, outlet glaciers, valley glaciers, and cirque glaciers, as well as ice caps. Ice features are grouped by location and a full description is available for each.

388

Satellite monitoring of glaciers in the Karakoram from 1977 to 2013: an overall almost stable population of dynamic glaciers  

NASA Astrophysics Data System (ADS)

Six hundred and seven glaciers of the Shigar, Shashghan, Nubra and part of Shyok sub-basins of the Karakoram region were monitored using satellite data of years 1977, 1990, 2000, 2001, 2002, 2004, 2006, 2008, 2009, 2010, 2011 and 2013. Landsat MSS, TM, ETM+ and IRS/Resourcesat-1 LISS III data were used. Glacier observations were classified into 3 categories such as advance, retreat or stable with reference to base data of 1977. Glaciers of the Karakoram have shown inconsistency in advance, retreat and no change during this period, and some examples of glacier surging have been caught in action. Despite significant geographic and temporal variability betraying the dynamic nature of many of the glaciers, in aggregate the population is roughly stable with less propensity toward retreat than most other glaciers in the nearby Himalaya and in the world. 341 glaciers exhibited no measured change throughout the 36 years of the study. Among other glaciers, no significant and sustained pattern of retreat or advance was observed. The overall changes in glacier area in the whole region are of small magnitudes (positive and negative values) in the various measured intervals. Moreover, it is mostly disconnected glaciers in tributary valleys which have advanced, whereas the main former trunk glaciers have primarily not changed. The dynamical differences between disconnected former tributaries and trunks may be related to response time differences, with the smaller, perhaps steeper tributaries responding more rapidly than trunks to brief climatic fluctuations. The advance/retreat fluctuations of many individual glaciers suggest that their response times primarily may be of order decades rather than some longer period, though some glaciers may have longer response times that have limited their length and area changes over the 36 year study period. The data from 2001 onwards were also utilized for finding annual changes of glaciers. Among the 607 glaciers, 10 show considerable fluctuation in their area; in several cases surge-waste cycles appear to be active. Glacier thickness change measurements are needed to aid our understanding of the regional glacier dynamics and relationships to climate change and area-response dynamics.

Brahmbhatt, R. M.; Bahuguna, I. M.; Rathore, B. P.; Singh, S. K.; Rajawat, A. S.; Shah, R. D.; Kargel, J. S.

2015-03-01

389

Reyes et al., p. 1 DATA REPOSITORY ITEM FOR: Expansion of alpine glaciers in Pacific North  

E-print Network

Reyes et al., p. 1 DATA REPOSITORY ITEM FOR: Expansion of alpine glaciers in Pacific North America in the first millennium A.D. Site Latitude Longitude (ºN) (ºW) Lillooet Glacier 50º45' 123º46' Bridge Glacier 50º49' 123º29' Miserable Glacier 51°04' 123°52' Tiedemann Glacier 51º21' 124º56' Frank Mackie Glacier

Barclay, David J.

390

Basaltic micrometeorites from the Novaya Zemlya glacier  

NASA Astrophysics Data System (ADS)

A large number of micrometeorites (MMs) was recovered from glacier deposits located at the north-eastern passive margin of the Novaya Zemlya glacier sheet. Melted, scoriaceous, and unmelted micrometeorites (UMMs) are present. Unmelted micrometeorites are dominated mostly by chondritic matter, but also a few achondritic MMs are present. Here we report the discovery of four UMMs that, according to their texture, mineralogy, and chemistry, are identified as basaltic breccias. Mineral chemistry and Fe/Mn ratios of two basaltic micrometeorites indicate a possible relationship with eucrites and/or mesosiderites, whereas two others seem to have parents, which appear not to be present in our meteorite collections. The basaltic breccia UMMs constitute 0.5% of the total population of the Novaya Zemlya MM suite. This content should be lowered to 0.25% because the Novaya Zemlya MM collection appears to be biased with carbonaceous UMMs being underrepresented.

Badjukov, Dmitry D.; Brandsttter, Franz; Raitala, Jouko; Kurat, Gero

2010-09-01

391

Microbial Life beneath a High Arctic Glacier  

Microsoft Academic Search

The debris-rich basal ice layers of a high Arctic glacier were shown to contain metabolically diverse microbes that could be cultured oligotrophically at low temperatures (0.3 to 4C). These organisms included aerobic chemoheterotrophs and anaerobic nitrate reducers, sulfate reducers, and methanogens. Colonies purified from subglacial samples at 4C appeared to be predominantly psychrophilic. Aerobic chemoheterotrophs were metabolically active in unfrozen

MARK L. SKIDMORE; JULIA M. FOGHT; MARTIN J. SHARP

2000-01-01

392

Observe how glaciers erode bedrock surfaces  

NSDL National Science Digital Library

In this interactive Earth science resource, students are first presented with six different photographs showcasing how glaciers can erode bedrock. Students are instructed to click on each labeled image to see an enlarged version of it. In the enlarged view, each photo is accompanied by a sentence or two that explains the glacial erosion shown. The images include features such as cirques, medial moraines, and striated bedrock. Copyright 2005 Eisenhower National Clearinghouse

TERC. Center for Earth and Space Science Education

2003-01-01

393

Global Warming and its Effects on Glaciers  

E-print Network

The addition of more greenhouse gasses to earths atmosphere has been blocking an increased amount of the heat radiated out from the earths surface. This in turn has lead to higher average global temperatures, or global warming. One of the main problems posed by this development is the melting of the earths glaciers. This is problematic because more liquid water will cause the planets sea levels to rise, possibly by as much as 66m if they are completely melted. Other environmental concerns related to melting include changes to mountain habitats and an accelerated water cycle. Although some modeling has shown no serious deterioration of the earths glaciers it is becoming increasingly evident that continued global warming would have serious repercussions on the planets ice. With the increasing acceptance of global warming as an important phenomenon occurring in our environment today, its effects on the natural cycles of the planet are becoming the center of research. One of the most interesting of these topics is the effect of global warming on the earths glaciers. It has been observed that increasing temperatures have and will continue to lead to glacial melting, and that the additional water will lead to a rise in the earths sea levels. The other potential effects of glacial melting are still the subject of controversy but it is becoming clear that natures equilibriums are being altered. Factors such as global warming have been blamed for the melting of the Earths glaciers. The overall global temperature has been increasing due to the greenhouse effect; over the past century the average global temperature has risen by about 0.5-0.6 degrees C (Bernarde, 1992). Around the turn of the century, Swedish chemist and

Andrew Grosvenor; Will Roble; Marcus De Castro

394

Climatic Significance of Holocene Glacier Fluctuations in New Zealand  

NASA Astrophysics Data System (ADS)

Holocene glacier fluctuations in New Zealand are represented by well-preserved moraine complexes in the Southern Alps. Recent cosmogenic dating of Holocene moraine sequences has allowed for interhemispheric comparisons of glacier advances and hence climate change. However, Balco (2009, Science, v 324, p 599-600) and others have asked "Can the timing and magnitude of observed past glacier changes in a particular region be explained by stochastic variability inherent in a steady climate, or is a change in the mean climate required?" To understand better the link between glaciers and climate during the Holocene, we evaluate possible past climate parameters by simulating ice extent at several well-preserved moraines deposited by the Cameron Glacier in the Arrowsmith Range, Southern Alps, New Zealand. We use a coupled 2-D ice-flow and distributed energy balance model with a snow transport component, the latter of which is necessary because, in its present-day configuration, this glacier receives a component of its accumulation from frequent snow avalanches. In our first experiment, we use steady-state simulations to identify the temperature and precipitation forcing required to fit the modelled Cameron Glacier to each of the geomorphically-defined moraine ridges. In our second experiment, we forced the glacier model with a time series of stochastic climate forcing that excludes a background temperature change. We discuss results of these tests, which permit assessment of the sensitivity and response of the Cameron Glacier to different modes of climate variability.

Doughty, A. M.; Mackintosh, A. N.; Anderson, B. A.; Putnam, A. E.; Barrell, D.; Denton, G.; Schaefer, J. M.

2012-12-01

395

Passive microwave (SSM/I) satellite predictions of valley glacier hydrology, Matanuska Glacier, Alaska  

USGS Publications Warehouse

We advance an approach to use satellite passive microwave observations to track valley glacier snowmelt and predict timing of spring snowmelt-induced floods at the terminus. Using 37 V GHz brightness temperatures (Tb) from the Special Sensor Microwave hnager (SSM/I), we monitor snowmelt onset when both Tb and the difference between the ascending and descending overpasses exceed fixed thresholds established for Matanuska Glacier. Melt is confirmed by ground-measured air temperature and snow-wetness, while glacier hydrologic responses are monitored by a stream gauge, suspended-sediment sensors and terminus ice velocity measurements. Accumulation area snowmelt timing is correlated (R2 = 0.61) to timing of the annual snowmelt flood peak and can be predicted within ??5 days. Copyright 2008 by the American Geophysical Union.

Kopczynski, S.E.; Ramage, J.; Lawson, D.; Goetz, S.; Evenson, E.; Denner, J.; Larson, G.

2008-01-01

396

Columbia Glacier stake location, mass balance, glacier surface altitude, and ice radar data, 1978 measurement year  

USGS Publications Warehouse

A 1 year data-collection program on Columbia Glacier, Alaska has produced a data set consisting of near-surface ice kinematics, mass balance, and altitude change at 57 points and 34 ice radar soundings. These data presented in two tables, are part of the basic data required for glacier dynamic analysis, computer models, and predictions of the number and size of icebergs which Columbia Glacier will calve into shipping lanes of eastern Prince William Sound. A metric, sea-level coordinate system was developed for use in surveying throughout the basin. Its use is explained and monument coordinates listed. A series of seven integrated programs for calculators were used in both the field and office to reduce the surveying data. These programs are thoroughly documented and explained in the report. (Kosco-USGS)

Mayo, L.R.; Trabant, D.C.; March, Rod; Haeberli, Wilfried

1979-01-01

397

A macroscopic approach to glacier dynamics  

USGS Publications Warehouse

A simple approach to glacier dynamics is explored in which there is postulated to be a relationship between area and volume with three parameters: the time for area to respond to changes in volume, a thickness scale, and an area characterizing the condition of the initial state. This approach gives a good fit to the measurements of cumulative balance and area on South Cascade Glacier from 1970-97; the area time-scale is roughly 8 years, the thickness scale about 123 m, and the 1970 area roughly 4% larger than required for adjustment with volume. Combining this relationship with a version of mass continuity expressed in terms of area and volume produces a theory of glacier area and volume response to climate in which another time constant, the volume time-scale, appears. Area and volume both respond like a damped spring and mass system. The damping of the South Cascade response is approximately critical, and the volume time-scale is roughly 48 years, six times the area time-scale. The critically damped spring and mass analogy reproduces the time dependence predicted by the more complicated traditional theory of Nye.

Harrison, W.D.; Raymond, C.F.; Echelmeyer, K.A.; Krimmel, R.M.

2003-01-01

398

New Species in New Guinea / Melting Glaciers  

NSDL National Science Digital Library

The first segment of this radio broadcast discusses a recent expedition to the isolated Foja mountain range in western New Guinea, which has discovered several new species of birds, 20 new frog species, and four new butterfly species, as well as a rare bird which had not been seen for sixty years, and unusual plants. One of the explorers discusses the efforts to map the diversity of the island and the challenges in preserving such ecological treasures. This segment is 12 minutes and 21 seconds in length. The second segment consists of a conversation with researchers who travel the world documenting the retreat of mountain glaciers. Topics include efforts to build a global database of ice cores to document changes; a discussion of increased water flow from glaciers; the logistics of drilling ice cores at high altitude and moving them to a university lab; how annual snowfall is recorded in ice cores; and how retreating glaciers are exposing plants that were covered for six thousand years. This segment is 35 minutes and 20 seconds in length.

399

Seasonal dynamic thinning at Helheim Glacier  

NASA Astrophysics Data System (ADS)

We investigate three annual mass-balance cycles on Helheim Glacier in south-east Greenland using TanDEM-X interferometric digital elevation models (DEMs), bedrock GPS measurements, and ice velocity from feature-tracking. The DEMs exhibit seasonal surface elevation cycles at elevations up to 800 m.a.s.l. with amplitudes of up to 19 m, from a maximum in July to a minimum in October or November, concentrated on the fast-flowing areas of the glacier indicating that the elevation changes have a mostly dynamic origin. By modelling the detrended bedrock loading/unloading signal we estimate a mean density for the loss of 671 70 kgm-3 and calculate that total water equivalent volume loss from the active part of the glacier (surface flow speeds >1 m day-1) ranges from 0.5 km3 in 2011 to 1.6 km3 in 2013. A rough ice-flux divergence analysis shows that at lower elevations (<200 m) mass loss by dynamic thinning fully explains seasonal elevation changes. In addition, surface elevations decrease by a greater amount than field observations of surface ablation or surface-energy-balance modelling predict, emphasising the dynamic nature of the mass loss. We conclude, on the basis of ice-front position observations through the time series, that melt-induced acceleration is most likely the main driver of the seasonal dynamic thinning, as opposed to changes triggered by retreat.

Bevan, Suzanne L.; Luckman, Adrian; Khan, Shfaqat A.; Murray, Tavi

2015-04-01

400

Global response of glacier runoff to twenty-first century climate change  

NASA Astrophysics Data System (ADS)

The hydrology of many important river systems in the world is influenced by the presence of glaciers in their upper reaches. We assess the global-scale response of glacier runoff to climate change, where glacier runoff is defined as all melt and rain water that runs off the glacierized area without refreezing. With an elevation-dependent glacier mass balance model, we project monthly glacier runoff for all mountain glaciers and ice caps outside Antarctica until 2100 using temperature and precipitation scenarios from 14 global climate models. We aggregate results for 18 glacierized regions. Despite continuous glacier net mass loss in all regions, trends in annual glacier runoff differ significantly among regions depending on the balance between increased glacier melt and reduction in glacier storage as glaciers shrink. While most regions show significant negative runoff trends, some regions exhibit steady increases in runoff (Canadian and Russian Arctic), or increases followed by decreases (Svalbard and Iceland). Annual glacier runoff is dominated by melt in most regions, but rain is a major contributor in the monsoon-affected regions of Asia and maritime regions such as New Zealand and Iceland. Annual net glacier mass loss dominates total glacier melt especially in some high-latitude regions, while seasonal melt is dominant in wetter climate regimes. Our results highlight the variety of glacier runoff responses to climate change and the need to include glacier net mass loss in assessments of future hydrological change.

Bliss, Andrew; Hock, Regine; Radi?, Valentina

2014-04-01

401

Glacier ice-volume modeling and glacier volumes on Redoubt Volcano, Alaska  

USGS Publications Warehouse

Assessment of ice volumes and hydrologic hazards on Redoubt Volcano began four months before the 1989-90 eruptions removed 0.29 cubic kilometer of perennial snow and ice from Drift glacier. A volume model was developed for evaluating glacier volumes on Redoubt Volcano. The volume model is based on third-order polynomial simulations of valley cross sections. The third-order polynomial is an interpolation from the valley walls exposed above glacier surfaces and takes advantage of ice-thickness measurements. The fortuitous 1989-90 eruptions removed the ice from a 4.5-kilometer length of Drift glacier, providing a unique opportunity for verification of the volume model. A 2.5-kilometer length was chosen in the denuded glacier valley and the ice volume was measured by digitally comparing two new maps: one derived from the most recent pre-eruption 1979 aerial photographs and the other from post-eruption 1990 aerial photographs. The measured volume in the reference reach was 99 x 106 cubic meters, about 1 percent less than was estimated by the volume model. The volume estimate produced by this volume model was much closer to the measured volume than was the volume estimated by other techniques. The verified volume model was used to evaluate the total volume of perennial snow and glacier ice on Redoubt Volcano, which was estimated to be 4.1?0.8 cubic kilometers. Substantial snow and ice covers on volcanoes exacerbate the hydrologic hazards associated with eruptions. The volume on Redoubt Volcano is about 23 times the volume that was present on Mount St. Helens before its 1980 eruption, which generated lahars and floods.

Trabant, Dennis C.; Hawkins, Daniel B.

1997-01-01

402

Controls on advance of tidewater glaciers: results from numerical modeling applied to Columbia Glacier  

E-print Network

and subfossil trees from glacier forefields. They showed that multidecadal long warm periods occurred around A.D. 1300, 1440, and possibly 1820 with cool intervals centered on A.D. 1400, 1660, and 1870. [10] The rapid retreat of Columbia Glacier has been mon... sedimentation. [33] The first modeling attempts to produce the observed terminus behavior involved climate forcing. Maintaining a stationary terminus at 61 km for a period of 300 years requires a substantial increase in ELA around A.D. 1400 followed by a...

Nick, F. M.; van der Veen, Cornelis J.; Oerlemans, J.

2007-07-11

403

A note on the water budget of temperate glaciers  

NASA Astrophysics Data System (ADS)

In this note the total dissipative melting in temperate glaciers is studied. The analysis is based on the notion that the dissipation is determined by the loss of potential energy, due to the downward motion of mass (ice, snow, meltwater and rain). A mathematical formulation of the dissipation is developed and applied to a simple glacier geometry. In a next step, meltwater production resulting from enhanced ice motion during a glacier surge is calculated. The amount of melt energy available follows directly from the lowering of the centre of gravity of the glacier. To illustrate the concept, schematic calculations are presented for a number of glaciers with different geometric characteristics. Typical dissipative melt rates, expressed as water-layer depth averaged over the glacier, range from a few cm per year for smaller glaciers to half a meter per year for Franz-Josef Glacier, one of the most active glaciers in the world (in terms of mass turnover). The total generation of meltwater during a surge is typically half a meter. For Variegated Glacier a value of 70 cm is found, for Kongsvegen 20 cm. These values refer to water layer depth averaged over the entire glacier. The melt rate depends on the duration of the surge. It is generally an order of magnitude larger than the water production by "normal" dissipation. On the other hand, the additional basal melt rate during a surge is comparable in magnitude to the water input from meltwater and precipitation. This suggests that enhanced melting during a surge does not grossly change the total water budget of a glacier. Basal water generated by enhanced sliding is an important ingredient of many theories of glacier surges. It provides a positive feedback mechanism that actually makes the surge happen. The results found here suggest that this can only work if water generated by enhanced sliding is accumulating in a part of the glacier base where surface meltwater and rain has no or very limited access. This finding seems compatible with the fact that on many glaciers surges are initiated in the lower accumulation zone.

Oerlemans, J.

2013-06-01

404

A note on the water budget of temperate glaciers  

NASA Astrophysics Data System (ADS)

In this note, the total dissipative melting in temperate glaciers is studied. The analysis is based on the notion that the dissipation is determined by the loss of potential energy due to the downward motion of mass (ice, snow, meltwater and rain). A mathematical formulation of the dissipation is developed and applied to a simple glacier geometry. In the next step, meltwater production resulting from enhanced ice motion during a glacier surge is calculated. The amount of melt energy available follows directly from the lowering of the centre of gravity of the glacier. To illustrate the concept, schematic calculations are presented for a number of glaciers with different geometric characteristics. Typical dissipative melt rates, expressed as water-layer depth averaged over the glacier, range from a few centimetres per year for smaller glaciers to half a metre per year for Franz Josef Glacier, one of the most active glaciers in the world (in terms of mass turnover). The total generation of meltwater during a surge is typically half a metre. For Variegated Glacier a value of 70 cm is found, for Kongsvegen 20 cm. These values refer to water layer depth averaged over the entire glacier. The melt textit{rate} depends on the duration of the surge. It is generally an order of magnitude greater than water production by `normal' dissipation. On the other hand, the additional basal melt rate during a surge is comparable in magnitude with the water input from meltwater and precipitation. This suggests that enhanced melting during a surge does not grossly change the total water budget of a glacier. Basal water generated by enhanced sliding is an important ingredient in many theories of glacier surges. It provides a positive feedback mechanism that actually makes the surge happen. The results found here suggest that this can only work if water generated by enhanced sliding accumulates in a part of the glacier base where surface meltwater and rain have no or very limited access. This finding seems compatible with the fact that, on many glaciers, surges are initiated in the lower accumulation zone.

Oerlemans, J.

2013-09-01

405

Holocene glacier history from alpine speleothems, Milchbach cave, Switzerland  

NASA Astrophysics Data System (ADS)

Mountain glaciers and their sediments are prominent witnesses of climate change, responding sensitively to even small modifications in meteorological parameters. Even in such a classical and thoroughly studied area as the European Alps the record of Holocene glacier mass-balance is only incompletely known. Here we explore a novel and continuous archive of glacier fluctuations in a cave system adjacent to the Upper Grindelwald Glacier in the Swiss Alps. Milchbach cave became partly ice-free only recently and hosts Holocene speleothems. Four coeval stalagmites show consistent petrographic and stable isotopic changes between 9.2 and 2.0 ka which can be tied to abrupt modifications in the cave environment as a result of the closing and opening of multiple cave entrances by the waxing and waning of the nearby glacier. During periods of Holocene glacier advances, columnar calcite fabric is characterized by ?18O values of about -8.0 indicative of speleothem growth under quasi-equilibrium conditions, i.e. little affected by kinetic effect related to forced degassing or biological processes. In contrast, fabrics formed during periods of glacier minima are typical of bacterially mediated calcite precipitation within caves overlain by an alpine soil cover. Moreover, ?18O values of the bacterially mediated calcite fabrics are consistent with a ventilated cave system fostering kinetic fractionation. These data suggest that glacier retreats occurred repeatedly before 5.8 ka, and that the amplitudes of glacier retreats became substantially smaller afterwards. Our reconstruction of the Upper Grindelwald Glacier fluctuations agrees well with paleoglaciological studies from other sites in the Alps and provides a higher temporal resolution compared to traditional analyses of peat and wood remains found in glacier forefields.

Luetscher, M.; Hoffmann, D. L.; Frisia, S.; Sptl, C.

2011-02-01

406

The length of the world's glaciers - a new approach for the global calculation of center lines  

NASA Astrophysics Data System (ADS)

Glacier length is an important measure of glacier geometry. Nevertheless, global glacier inventories are mostly lacking length data. Only recently semi-automated approaches to measure glacier length have been developed and applied regionally. Here we present a first global assessment of glacier length using an automated method that relies on glacier surface slope, distance to the glacier margins and a set of trade-off functions. The method is developed for East Greenland, evaluated for East Greenland as well as for Alaska and eventually applied to all ~ 200 000 glaciers around the globe. The evaluation highlights accurately calculated glacier length where digital elevation model (DEM) quality is high (East Greenland) and limited accuracy on low-quality DEMs (parts of Alaska). Measured length of very small glaciers is subject to a certain level of ambiguity. The global calculation shows that only about 1.5% of all glaciers are longer than 10 km, with Bering Glacier (Alaska/Canada) being the longest glacier in the world at a length of 196 km. Based on the output of our algorithm we derive global and regional area-length scaling laws. Differences among regional scaling parameters appear to be related to characteristics of topography and glacier mass balance. The present study adds glacier length as a key parameter to global glacier inventories. Global and regional scaling laws might prove beneficial in conceptual glacier models.

Machguth, H.; Huss, M.

2014-09-01

407

Glacier-sea floor interactions during advance-retreat cycles of surge-type glaciers in Svalbard (Invited)  

NASA Astrophysics Data System (ADS)

In Svalbard, many fjord-terminating glaciers are surge-type, and surges profoundly influence fjord-floor landsystems and sediment architecture. Conversely, moraines and other glacigenic landforms influence glacier terminus stability by acting as pinning points and barriers to glacier flow. We use a combination of Synthetic Aperture Radar (SAR) satellite imagery and detailed bathymetric surveys to investigate the evolution of several fjord-terminating glaciers during recent surges, and their relationship with sea floor topography and landforming processes. During surges, glaciers transport large quantities of fjord floor sediment in the form of mobile push moraines, which can form substantial barriers across fjords. These moraines suppress calving during surge advances by acting as pinning points, and encourage glacier stability during early quiescence. Consequently, calving rates do not vary systematically over the course of a surge cycle, despite large variations in glacier flow speeds. Geomorphological and sedimentological data show that many Svalbard surge moraines are multi-generational, and that repeated surges terminated at similar points in the fjord. Unlike land-terminating surge-type glaciers, fjord-terminating glaciers can build sequences of annual push moraines during their quiescent phases. These recessional moraines can form even in front of stagnant glaciers, when their frontal zones undergo stretching in response to longitudinal stress gradients. In conjunction with surge moraines, these provide an important record of advance-retreat dynamics of surge-type glaciers, in some cases over multiple surge cycles. When combined with dating techniques, this landform assemblage can provide important information about the frequency and magnitude of Svalbard surges well beyond the observational record.

Benn, D.; Flink, A.; Lovell, H.; Luckman, A. J.; Noormets, R.; Sevestre, H.

2013-12-01

408

AK-03 ALASKA: AK-03 Columbia Glacier "Cliff" (Narrated)  

NSDL National Science Digital Library

A video from the Extreme Ice Survey in which Dr. Tad Pfeffer and photographer Jim Balog discuss the dynamics of the Columbia glacier's retreat in recent years through this time-lapse movie. Key point: glacier size is being reduced not just by glacial melting but due to a shift in glacial dynamics brought on by climate change.

James Balog

409

Profiles of Late Pleistocene Glaciers in New Zealand  

Microsoft Academic Search

Glaciological theory indicates that, as a first approximation, surface slope of a valley glacier is inversely proportional to depth for a given cross-sectional shape. Data are available on surface slope, depth, cross-sectional shape, and elevation of the floor for the lower parts of the Late Pleistocene (Otiran) glaciers of the Tasman and Godley Valleys, permitting an assessment of the constant

W. H. Mathews

1967-01-01

410

Holocene Glacier Fluctuations in the Peruvian Andes Indicate Northern  

E-print Network

chronologies differ from the New Zealand record but are broadly correlative with well-dated glacial recordsHolocene Glacier Fluctuations in the Peruvian Andes Indicate Northern Climate Linkages Joseph M. Tropical glacier fluctuations provide important insight on regional paleoclimatic trends and forcings

Licciardi, Joseph M.

411

On the Veined Structure of the Mueller Glacier, New Zealand  

Microsoft Academic Search

THE Mueller Glacier, in the Mount Cook district, has a total length of between six and seven miles, with a breadth of one mile in its lower portion. Like most, if not all, of the New Zealand glaciers of the first order, the lower mile or two is so thickly covered with rock debris that the ice can only be

F. W. Hutton

1888-01-01

412

Sensitivity and response of Bhutanese glaciers to atmospheric warming  

NASA Astrophysics Data System (ADS)

Glacierized change in the Himalayas affects river-discharge, hydro-energy and agricultural production, and Glacial Lake Outburst Flood potential, but its quantification and extent of impacts remains highly uncertain. Here we present conservative, comprehensive and quantitative predictions for glacier area and meltwater flux changes in Bhutan, monsoonal Himalayas. In particular, we quantify the uncertainties associated with the glacier area and meltwater flux changes due to uncertainty in climate data, a critical problem for much of High Asia. Based on a suite of gridded climate data and a robust glacier melt model, our results show that glacier area and meltwater change projections can vary by an order of magnitude for different climate datasets. However, the most conservative results indicate that, even if climate were to remain at the present-day mean values, almost 10% of Bhutan's glacierized area would vanish and the meltwater flux would drop by as much as 30%. Under the conservative scenario of an additional 1C regional warming, glacier retreat is going to continue until about 25% of Bhutan's glacierized area will have disappeared and the annual meltwater flux, after an initial spike, would drop by as much as 65%.

Rupper, Summer; Schaefer, Joerg M.; Burgener, Landon K.; Koenig, Lora S.; Tsering, Karma; Cook, Edward R.

2012-10-01

413

Glacier sensitivity and regional climate: Past and present  

Microsoft Academic Search

This study develops a surface energy- and mass-balance model with which to understand the interactions between glaciers and climate on regional-scales. This model is applied to Central Asia because of the diverse climate regimes and glacier history. The model is used to understand the sensitivity of equilibrium line altitudes (ELAs) to modern interannual climate variability, and to reconcile patterns of

Summer Burton Rupper

2007-01-01

414

Central Asian Glacier Sensitivity and Regional Climate: Past and Present  

Microsoft Academic Search

A surface energy- and mass-balance model that captures the interactions between glaciers and climate on regional-scales is presented. The model is applied to Central Asia because of the diverse climate regimes and unusual glacier history. It is used to understand the sensitivity of equilibrium line altitudes (ELAs) to modern interannual climate variability, and to reconcile patterns of ELA changes with

S. Rupper; G. Roe; A. Gillespie

2007-01-01

415

36 CFR 7.3 - Glacier National Park.  

Code of Federal Regulations, 2010 CFR

...Medicine entrance to Two Medicine Lake; from West Glacier entrance to the Camas Entrance; U.S. Highway 2 from Walton to Java; and the Going-to-the-Sun Road from West Glacier entrance to Lake McDonald Lodge and from St. Mary entrance to...

2010-07-01

416

Interim report of fluoride pollution in Glacier National Park  

Microsoft Academic Search

Data and inferences pertinent to Glacier National Park drawn from vegetation collected in July 1970 and analyzed for injury and total fluoride content are presented. Samples collected along radii extending from the Anaconda Aluminum Company reduction plant at Columbia Falls, Montana, into Glacier National Park showed conclusively that injury caused by fluoride pollution to plants is occurring in the Park,

1970-01-01

417

Muir and Riggs Glaciers, Muir Inlet, Alaska - 2004  

USGS Multimedia Gallery

The second repeat photograph documents significant changes that have occurred during the 63 years between photographs A and C, and during the 54 years between photographs B and C. Muir Glacier has retreated out of the field of view and is now more than 7 kilometers northwest. Riggs Glacier has retre...

418

Large fluctuations in speed on Greenland's Jakobshavn Isbr glacier  

Microsoft Academic Search

It is important to understand recent changes in the velocity of Greenland glaciers because the mass balance of the Greenland Ice Sheet is partly determined by the flow rates of these outlets. Jakobshavn Isbr is Greenland's largest outlet glacier, draining about 6.5 per cent of the ice-sheet area, and it has been surveyed repeatedly since 1991 (ref. 2). Here we

Ian Joughin; Waleed Abdalati; Mark Fahnestock

2004-01-01

419

Glacier Bay, Alaska, From the Ground, Air and Space  

NSDL National Science Digital Library

This video shows how a NASA glaciologist has learned about glaciers and how their formation could be related to climate change. It features nine fly-bys over 3-dimensional glaciers, live video footage of ice fronts calving into the sea, and picture sequences of historical and satellite data.. Length:13:15.

1996-01-01

420

What influences climate and glacier change in southwestern China?  

Microsoft Academic Search

The subject of climate change in the Tibetan Plateau (TP) and Himalayas has taken on increasing importance because of the availability of water resources from their mountain glaciers (Immerzeel et al 2010). Many of the glaciers over these regions have been retreating, while some are advancing and stable (Yao et al 2004, Scherler et al 2011). Other studies report that

Teppei J. Yasunari

2011-01-01

421

A century of glacier change in the American West  

NASA Astrophysics Data System (ADS)

Over the past 100 years glaciers in the American West (exclusive of Alaska) have largely receded. The magnitude of the recession varies across the west, with the greatest loss in Montana and California (>50% area loss) and the least loss on the stratovolcanoes (>35%) of the Pacific Northwest. The variations can be broadly characterized by elevation. Our results suggest that increased mass loss caused by increased summer temperatures affect all glaciers, whereas increasing winter temperatures, that change the phase of precipitation from snow to rain adversely affect those glaciers less than 3000m in elevation. The high glaciers (>3000m) of California and Colorado appear to be immune to variations in snowfall making them sensitive to variations in temperature alone. We infer that these very small, steep glaciers can only hold a given amount of snow beyond which extra snow avalanches or is blown off. Conversely, during winters of little direct snowfall, additional snow may be added through win drift from the surrounding terrain. The relatively little glacier shrinkage on the stratovolcanoes is due to the high altitude of the glacier accumulation zones. An east to west decrease in glacier shrinkage from Montana through Washington is due to enhanced winter precipitation along the west coast that somewhat buffers ice loss due to summer temperatures and winter precipitation phase changes.

Fountain, A. G.

2007-12-01

422

ENVIRONMENTAL HAZARDS OF AVALANCHES: PRELIMINARY RESEARCH IN GLACIER NATIONAL  

E-print Network

ENVIRONMENTAL HAZARDS OF AVALANCHES: PRELIMINARY RESEARCH IN GLACIER NATIONAL PARK Site Focus: Balu Pass, Glacier National Park, B.C. Avalanche path near Balu Pass. (Photo Courtesy of: www in avalanche areas? #12;Researchers · Ben Ferrel · Keri Laughlin · Kevin McPhedran · Mark Brown · also thanks

Smith, Dan

423

Mass fluxes and dynamics of Moreno Glacier, Southern Patagonia Icefield  

Microsoft Academic Search

Accumulation, ablation, calving, and flow dynamics of Moreno Glacier, one of the main outlet glaciers of the Southern Patagonia Icefield, were studied based on field campaigns and on spaceborne radar imagery acquired by SIR-C\\/X-SAR. Ice velocities and ablation were measured through two summers and one winter. The ice depth was sounded seismically at a transect 8 km above the calving

Helmut Rott; Martin Stuefer; Andreas Siegel; Pedro Skvarca; Alfons Eckstaller

1998-01-01

424

Twentieth century climate change: Evidence from small glaciers  

Microsoft Academic Search

The relation between changes in modern glaciers, not including the ice sheets of Greenland and Antarctica, and their climatic environment is investigated to shed light on paleoglacier evidence of past climate change and for projecting the effects of future climate warming on cold regions of the world. Loss of glacier volume has been more or less continuous since the 19th

Mark B. Dyurgerov; Mark F. Meier

2000-01-01

425

Transport of heat and salt driven by remote shelf winds in a glacial fjord of East Greenland  

NASA Astrophysics Data System (ADS)

Greenland's glacial fjords form a key link in the climate system between the open ocean and the ice sheet's outlet glaciers. The circulation in these fjords controls heat transport to the glaciers and submarine melting, thereby potentially affecting glacier behavior and the mass balance of the Greenland Ice Sheet. Here, we use ocean data from Sermilik Fjord, where Helheim Glacier drains, to quantify the circulation and identify the leading order drivers. Using three years of moored velocity and CTD records and ERA Interim Reanalysis wind fields, we find evidence of a strong fjord response to remote winds on the shelf. Large along-shore winds events (called barrier winds in this region) drive isopycnal movements on the shelf and subsequent baroclinic flows within the fjord. Beyond an intense transient response throughout the length of the fjord, these flows can also trigger a marked shift in properties both in the outflowing glacial meltwater and the inflowing ocean water within the fjord. The interaction between the freshwater input from the glacier and the remote forcing from winds on the shelf is examined.

Jackson, R. H.; Straneo, F.; Sutherland, D. A.

2012-12-01

426

A physically based calving model applied to marine outlet glaciers and implications for the glacier dynamics  

E-print Network

We present results from numerical ice-flow models that include calving criteria based on penetration of surface and basal crevasses, which in turn is a function of longitudinal strain rates near the glacier front. The position of the calving front...

Van Der Veen, Cornelis J.; Nick, F. M.; Vieli, A.; Venn, D. I.

2010-11-05

427

Source-to-sink study of erosion at Grinnell Glacier, Glacier National Park, Montana  

Microsoft Academic Search

Cirques have been used as proxies for past climatic conditions, yet the detailed physical processes that act to form cirques remain poorly understood. In July 2005, we continued a field study at Grinnell Glacier in Montana to examine the relevant glacial and geomorphic processes driving cirque development. As in July 2004, we installed a grid of nine velocity poles to

C. A. Riihimaki; K. R. MacGregor

2005-01-01

428

Mapping the Retreat of the Asulkan Glacier in Glacier National Park, British Columbia, Canada  

E-print Network

, five dating techniques were applied: lichenometry, dendrochronology, moraine interpretation. This data was used in support of the dendrochronology results for the purposes of mapping retreat. Surveys with the other dating techniques, enabled us to map the Asulkan glacier's gradual recession. Dendrochronology

Smith, Dan

429

Source-to-sink study of erosion at Grinnell Glacier, Glacier National Park, Montana  

NASA Astrophysics Data System (ADS)

Cirques have been used as proxies for past climatic conditions, yet the detailed physical processes that act to form cirques remain poorly understood. In July 2005, we continued a field study at Grinnell Glacier in Montana to examine the relevant glacial and geomorphic processes driving cirque development. As in July 2004, we installed a grid of nine velocity poles to measure ice motion using differential GPS, and several temperature sensors and snow stakes to monitor snow and ice melt across Grinnell Glacier. We supplemented these data with time-series of 15-minute measurements of snow and ice melt recorded by an ultrasonic ranging sensor. Air temperature and snowmelt correlate well, with diurnal fluctuations in melt corresponding to diurnal temperature fluctuations. The ultrasonic sensor recorded an average melt rate of snow over the 24-day period of observation of 3.5 cm d-1 (water equivalent), with average daily rates as high as 6 cm d-1. Melt rates declined as snowmelt revealed debris-covered ice below. These observations suggest that debris-cover may play an important role in insolating Grinnell Glacier from summer melt, particularly in coming decades as debris concentrations are expected to rise. Average velocity near the center of the glacier, where ice thickness was ~44 meters, was ~5 cm d-1 during this time. Our measurements span the period of earthquake activity that occurred in Montana July 25-27. Iceberg calving was associated with the ground shaking. Downstream from Grinnell Glacier, we collected 5 lake cores to document sedimentation rates in Swiftcurrent and Josephine Lakes, source areas for erosion in the drainage basin, and environmental change due to forest fires and changes in vegetation. Two cores from Swiftcurrent Lake and one core from Lake Josephine are >5 m in length, providing us one of the first high-resolution lake records in Glacier National Park. While the core analysis remains a work-in-progress, preliminary work indicates that the cores document changes in charcoal abundance, organic matter, and sedimentation rates during the Quaternary. Future work will focus on determining erosion rates of Grinnell Glacier based on sedimentation rates in downstream sediment cores.

Riihimaki, C. A.; MacGregor, K. R.

2005-12-01

430

Bathymetric control of tidewater glacier mass loss in northwest Greenland  

NASA Astrophysics Data System (ADS)

It has been suggested that fjord geometry could be an important contributor to the observed mass loss variability in Greenland by modulating the flow of warm water to marine-terminating glaciers. New gravity-derived bathymetry of Greenlandic fjords confirms the link between the grounding line depth and rates of glacier mass loss, a relationship previously predicted only in ice models. We focus on two neighboring glaciers to minimize differences in external forcing and therefore isolate the role of the fjord bathymetry. Tracy Glacier has a deeper grounding line and has been retreating since 1892 with a contemporary mass budget of -1.63 Gt a-1. Heilprin Glacier has a shallower grounding line depth, a stable ice terminus, and a mass budget of only -0.53 Gt a-1. Because of its deeper grounding line, Tracy has more ice in contact with warm subsurface water, leaving it more vulnerable to changes in ocean forcing and therefore mass loss.

Porter, David F.; Tinto, Kirsty J.; Boghosian, Alexandra; Cochran, James R.; Bell, Robin E.; Manizade, Serdar S.; Sonntag, John G.

2014-09-01

431

Exploring tidewater glacier retreat using past and current observations at Columbia Glacier, Alaska. (Invited)  

NASA Astrophysics Data System (ADS)

Since fulfilling Austin Posts prediction of impending retreat in the late 1970s, Columbia Glacier has repeatedly surprised both casual and careful observers with its ability for rapid change. Over the last three decades, Columbia Glacier has lost approximately 18 km of its original 66 km length, while thinning by approximately 50% at the present terminus. The total ice volume lost to the Gulf of Alaska Estimates upwards of 120 km3 constrain the total ice volume lost to the Gulf of Alaska. Recently, the terminus supported a ~1.5 km long floating tongue for over than a year, contradicting the common assumption that the mechanical properties of temperate ice prohibit flotation over sustained time intervals. The rich history of study offers an opportunity to better understand tidewater glacier retreat, and a valuable analog to the dynamic instability underway at several ice sheet outlet glaciers. Current research aims to improve processing resolution of existing aerial photographic data, while complimenting the 30-year photogrammetric record with a suite of field observations. Recent instrumentation includes: oblique time lapse and still imagery, semi-permanent GPS, airborne radar, mass balance, passive seismology and LiDAR. This presentation will focus on innovative methods developed in recent field seasons, sharing insight each has provided into the retreat process . 1The Columbia Glacier Consortium consists of: Fabian Walter (SIO), Kenichi Matsuoka (NPI), Ben Smith (UW), Ethan Welty (CU-Boulder), Chris Larsen (UAF), Dave Finnegan (CRREL), Dan McNamara (USGS), Yushin Ahn (OSU), Julie Markus (OSU), Adam LeWinter (EIS).

O'Neel, S.; Pfeffer, W. T.; Howat, I. M.; Conway, H.; Columbia Glacier Consortium

2010-12-01

432

Photogrammetric Monitoring of Glacier Margin Lakes  

NASA Astrophysics Data System (ADS)

The growing number of glacial margin lakes that have developed due to glacier retreat, have caused an increase of dangerous Glacial Lake Outburst Floods (GLOFs) in several regions over the last decade. A GLOF can occur when the water from the lake finds a path underneath the bottom of the glacier and the lake is draining rapidly. This causes normally a flood wave downstream the glacier. Typically such an event takes about 24 hours. GLOF scenarios may be a significant hazard to life, property, nature and infrastructure in the affected areas. Together with our partner institute CECS (Valdivia, Chile), a project was initiated on a pilot study for an early warning system for GLOF events in the Northern Patagonian Icefield. A GLOF is normally characterized by a progressive water level drop. By observing the water level of the lake, an imminent GLOF-event can be identified. Common gauging systems are not suitable for the measurement task, as they may be affected by ice fall or landslides in the lake basin. Therefore, in our pilot study the water level is observed by processing images of a terrestrial camera system. The paper presents the basic principle of a single-camera based GLOF early warning system. Challenges and approaches to solve them are discussed. First results from processed image sequences are presented to show the feasibility of the concept. Water level changes can be determined at decimetre precision. In the first stage of the project, the waterline was measured manually in the images. A promising approach for reliable automation of this task is the use of a camera, which is sensitive for near infrared. The difference in the reflection of water, ice, and rock in this wavelength is more better than in RGB. This will be discussed in the outlook in deep.

Mulsow, C.; Koschitzki, R.; Maas, H.-G.

2013-01-01

433

Timing of Holocene Glacier Recessions in the Swiss Alps  

NASA Astrophysics Data System (ADS)

Alpine glaciers are sensitive climate indicators on time scales as short as decades to centuries. Periods of cold and wet climatic conditions cause glacial advances and deposition of moraines. Subsequent change to warmer and drier conditions cause glacial recessions. Since the cold event of the Little Ice Age glaciers in the Swiss Alps have retreated substantially exposing high walls of lateral moraines which consist of a stack of overlying till units. Previous work focused on such stacked moraines and the related glacial advances. However, such paleoclimatic reconstructions based only on moraines are incomplete, in particular for periods of glacial recession. This study examines Holocene glacier recessions based on pieces of wood and peat occurring in glaciofluvial deposits of outburst flood events. These subfossil remains indicate that (i) glaciers were once smaller than present, (ii) climate conditions allowed vegetation growth and a higher treeline elevation than today, (iii) sequences of glaciofluvial gravels and lodgement tills accumulated in now glaciated basins. We focus in this study on three climaticly different re-gions: i.e. Unteraar Glacier (Central Alps), Tschierva Glacier (Eastern Alps) and Ried Glacier (South Central Alps). The conventional radiocarbon and AMS dating was used to determine the age of more than 140 samples of wood and peat fragments. The results show that glacier recessions occurred in distinct phases throughout the Holocene, synchronously in different Alpine regions. The total duration of recession phases is longer than 5500 yr or > 50 % of the Holocene epoch. The glacial recessions are separated by glacial advances, which occurred in time periods shorter than 400 yr. A comparison of our Holocene record of glacier length variations with the ice rafted debris events in the North Atlantic, the Be-10 record of ice cores and atmospheric ? 14C suggest a combination of solar and North Atlantic forcing. Thus, situations of glacial recession, to the extent of smaller glaciers than present, occurred throughout the Holocene.

Joerin, U. E.; Stocker, T. F.; Schluechter, C.

2004-12-01

434

Botanical Evidence of the Modern History of Nisqually Glacier, Washington  

USGS Publications Warehouse

A knowledge of the areas once occupied by mountain glaciers reveals at least part of the past behavior of these glaciers. From this behavior, inferences of past climate can be drawn. The maximum advance of Nisqually Glacier in the last thousand years was located, and retreat from this point is believed to have started about 1840. The maximum downvalley position of the glacier is marked by either a prominent moraine or by a line of difference between stands of trees of strikingly different size and significantly different age. The thousand-year age of the forest beyond the moraine or line between abutting stands represents the minimum time since the surface was glaciated. This age is based on the age of the oldest trees, plus an estimated interval required for the formation of humus, plus evidence of an ancient fire, plus an interval of deposition of pyroclastics. The estimate of the date when Nisqually Glacier began to retreat from its maximum advance is based upon the ages of the oldest trees plus an interval of 5 years estimated as the time required for the establishment of trees on stable moraines. This interval was derived from a study of the ages of trees growing at locations of known past positions of the glacier. Reconnaissance studies were made on moraines formed by Emmons and Tahoma Glaciers. Preliminary analyses of these data suggest that Emmons Glacier started to recede from its maximum advance in about 1745. Two other upvalley moraines mark positions from which recession started about 1849 and 1896. Ages of trees near Tahoma Glacier indicate that it started to recede from its position of maximum advance in about 1635. About 1835 Tahoma Glacier started to recede again from another moraine formed by a readvance that ter minated near the 1635 position.

Sigafoos, Robert S.; Hendricks, E.L.

1961-01-01

435

A revised Canadian perspective: progress in glacier hydrology  

NASA Astrophysics Data System (ADS)

Current research into glacier hydrology is occurring at a time when glaciers around the world, particularly those whose hydrological regimes affect populated areas, are shrinking as they go through a state of perpetual negative annual mass balance. Small glaciers alone are likely to contribute 0·5 to 1 mm year-1 to global sea-level rise, with associated reductions in local freshwater resources, impacts upon freshwater ecosystems and increased risk of hazard due to outburst floods. Changes to the accumulation regimes of glaciers and ice sheets may be partly responsible, so the measurement and distribution of snowfall in glacierized basins, a topic long represented in non-glacierized basin research, is now beginning to receive more attention than it did before, aided by the advent of reliable automatic weather stations that provide data throughout the year. Satellite data continue to be an important information source for summer meltwater estimation, as distributed models, and their need for albedo maps, continue to develop. This further entails the need for simplifications to energy balance components, sacrificing point detail so that spatial calculation may proceed more quickly. The understanding of surface meltwater routing through the glacier to produce stream outflow continues to be a stimulating area of research, as demonstrated by activity at the Trapridge Glacier, Canada, and Canadian involvement in the Haut Glacier d'Arolla, Switzerland. As Canadian glacier monitoring continues to evolve, effort must be directed toward developing situations where mass balance, meltwater generation and flow routing studies can be done together at selected sites. Copyright

Munro, D. Scott

2005-01-01

436

Counting Glaciers: Use of Scaling Methods to Estimate the Number and Size Distribution of the Glaciers of the World  

Microsoft Academic Search

Global aqd regional syntheses of glacier melt and runoff are needed for under- standing present and future sea-level rise, as well as for hydrological and climato- logical analyses. Observational data on glacier areas are needed for modeling gla- cier-climate interactions and runoff, but are available for only a few regions. Data on the distributions of sizes and thicknesses are critical

M. F. MEIER; D. B. BAHR

437

Application of Near-Surface Geophysics to Problems in Glacier Dynamics, Pitted Outwash Plain Formation, and Glaciotectonics, Matanuska Glacier, Alaska  

Microsoft Academic Search

From 2000 to 2004, near-surface geophysics data in various forms was collected near the active terminus of Matanuska Glacier, Alaska, to address several specific hypotheses and also provide general subsurface information in several relatively unsampled zones of the subsurface. (1) Seismic reflection data was collected on the glacier to test the predicted thickening of debris-rich basal ice in response to

G. S. Baker; K. Pyke; E. Evenson; D. Lawson; G. Larson; R. B. Alley

2005-01-01

438

The application of glacier inventory data for estimating past climate change effects on mountain glaciers: A comparison between the  

E-print Network

glaciers: A comparison between the European Alps and the Southern Alps of New Zealand M. Hoelzle a,c,, T This study uses the database from national glacier inventories in the European Alps and the Southern Alps, and applies to the mid-1970s. Only 1763 (35%) for the European Alps and 702 (22%) for the New Zealand Alps

439

Wild Wind  

NSDL National Science Digital Library

Students learn the difference between global, prevailing and local winds. They make wind vanes out of paper, straws and soda bottles and use them to measure wind direction over time. They analyze their data to draw conclusions about the local prevailing winds.

2014-09-18

440

Meteorology (Wind)  

Atmospheric Science Data Center

Wind speed at 50 m (m/s) The average and percent difference minimum and ... are given. Percent of time for ranges of wind speed at 50 m (percent) Percentage [frequency] of time that wind ... be adjusted to heights from 10 to 300 meters using the Gipe power law. Wind speeds may be adjusted for different terrain by selecting from ...

2014-09-25