Glaciers are large, dense accumulations of snow and ice that form on land where snowfall exceeds melting over many years. They are distinct from sea ice and lake ice. Glaciers cover 10% of the world's land area and store the largest reservoir of fresh water on Earth. The scientific study of glaciers is called glaciology and involves understanding their relationships with climate, sea levels, and impacts on humans and the environment. Remote sensing techniques such as aerial photography, satellite imagery, and radar are powerful tools for monitoring and mapping glaciers, which are often located in remote areas. Different sensors can detect glacial features, measure glacier flow velocities, and help determine mass balances and snowmelt runoff.

2. WHAT ARE GLACIERS?
 Dense ice
 Accumulation of snow exceeds its ablation over many years
 Form only on land
 Change landscapes due to their weight when they flow
through
 Distinct from thinner sea ice and lake ice that form on the
surface of bodies of water
 Cover 10% of world’s land
 99% of glacial ice contained in the polar regions
 Largest reservoir of fresh water on Earth
 Store water as ice during the colder seasons
 Released as warmer summer temperatures cause them to
melt 2

3. GLACIOLOGY
 Scientific study of glaciers
 Integrates oceanography, geology, climatology,
meteorology, etc.
 Glacial rivers of ice help regulate Earth’s weather
 Relationships between glacial melting and rise in sea
levels
 Determine how strong or long-lasting the green house
effect may come
 Impacts on human and environment
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4. APPLICATIONS
 Powerful and efficient method of gathering data about
glaciers.
 Study glaciers usually located in remote, inaccessible and
inhospitable environments.
 Recent advent of GIS and GPS creates effective means by
which the acquired data are analysed for effective monitoring
and mapping of temporal dynamics of glaciers.
 Traditional visible/infrared remote sensing of 2-D glacier
distribution extended to 3-D volume estimation and dynamic
monitoring using radar imagery and GPS.
 Longitudinal variations in glacial extent detected from
multitemporal images in GIS.
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5.  Studied from both airborne and space-borne platforms.
 Sensors mounted on these platforms enable glaciers at
various conditions to be captured.
 Launch of Landsat in early 1970s aroused tremendous
interest in applying RS to various sub-fields in glaciology.
 Advent of GIS further facilitates detection of glaciers and
evolution of their spatial extent from multi-temporal
images.
 Speed and accuracy of GPS techniques suitable for
repeated glacier mapping.
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6. To detect glacial features
 Spectrally discernible from air or space.
 Spectral reflectance of glacier ice, fresh snow and firn in
the visible and SWIR regions of the spectrum (Fig 1).
 Gradually decreases from 95% to 60% within visible range
while snow is metamorphosed to glacier ice.
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Fig 1: Spectral reflectance curves for fresh snow, firn, glacier ice and dirty
glacier ice in Northwest China

8. 8
Remote sensing materials that have found applications in glaciology

9.  VNIR – camera
 Photographs captured by a film mounted in a camera
 Vertical frame aerial photographs have finest spatial resolution
owing to low flight height and long focal lens of aerial cameras.
 Accurate mapping small-scale glaciers interpretion.
 Aerial photographs advantageous in detailed studies
 Delineation of glacier tongues
 Determination of position of glacial termini
 Mapping of snowline
 Detection of spatial fluctuations of glaciers over an area where
satellite imagery is nonexistent.
 Glacier boundaries mapped easily with ptical sensor.
 If taken on repetitive basis, most effective means of
monitoring changes in glaciers
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10. VNIR – air-borne scanning
 Sensor mounted in an aeroplane
 Scanner acquire great number of spectral bands of
imagery during one scan.
 An example - Airborne Visible/Infrared Imaging
Spectrometer (AVIRIS) sensor.
 AVIRIS imagery is highly effective at detecting high clouds
over snow- and ice-covered surfaces in the Arctic.
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11. VNIR – space-borne scanning
 Record repeatedly over a long period.
 Long-term monitoring of glaciers possible.
 Provides large areal coverage.
 Suitable for mapping glaciers when aerial surveys are
impossible to carry out or where glaciers change rapidly.
 Reveals direction of ice flow that is not possible to detect on
aerial photographs.
 Earth resources satellite imagery such as Landsat and SPOT has
an intermediate spatial resolution on the order of 10 to 79 m.
 Landsat series of satellites with sensors: Return Beam Vidicon
(RBV), Multi-Spectral Scanner (MSS) and Thematic Mapper
(TM).
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12.  RBV not widely used in glacier studies.
 Landsat MSS imagery more valuable in glaciology.
 Glacier outlines may be used to update old or inaccurate
maps.
 MSS with 79-m resolution used to identify and classify
glaciers and to detect changes in snow-covered areas.
 MSS too coarse to study small alpine glaciers and identify
glacier boundaries.
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13.  TM imagery with 30m spatial resolution and 7 bands
spectral resolution.
 Suitable for snow/cloud discrimination.
 TM images can be used to distinguish between blue ice
and snow.
 Differentiate various types of ice
 In comparison with Landsat data, SPOT imagery has
neither the broad areal coverage nor the high spectral
resolution.
 Consequently, SPOT data have rarely used in glaciology.
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14. Microwave remote sensing
 Two broad categories: Imaging and Nonimaging radar.
 Imaging radar: Shuttle Imaging Radar (SIR), European Space
Agency (ESA) ERS-1 and ERS-2, Japanese J-ERS1, Seasat
Synthetic Aperture Radar (SAR) and Canadian Radarsat.
 Spectral bands commonly used in these systems: X, C and L, all
provide glaciological information.
 In particular, X and C bands are used for mapping wet snow
packs.
 SAR data (C-band) can discriminate snow- from nonsnow-
covered areas.
 Together with ERS-1 data, Radarsat imagery monitor retreating
glaciers.
 Nonimaging radar systems such as airborne laser altimeter
(ALA) and radio echo sounding determine ice thickness,
estimate glacier temperature, etc.
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15. IDENTIFIABLE GLACIER FEATURES
 Glaciological features successfully studied:
 Mapping of glaciers
 Monitoring of their spatial variations
 Determination of flow velocity
 Estimation of mass balance
 Modelling of snowmelt runoff.
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16. Mapping of glaciers
 Glacier inventory provides an estimate of freshwater
storage
 GIS is an efficient tool for analysing current state and
changes in glaciers
Monitoring of spatial variations
 GIS is an efficient tool for analysing current state and
changes in glaciers
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17. Determination of glacier velocity
 Compared with sequential satellite images, GPS is more
advantageous.
 On the other hand, GPS is disadvantaged by the problem of
accessibility.
Snow/ice differentiation
 Differentiate various types of ice from Landsat MSS, TM and
SPOT images.
 MSS-5 most useful for depicting snow, firn, clean ice, debris-
covered snow and moraine.
 Microwave RS imagery more capable of differentiating snow
from ice.
 Scree/talus, dry snow, dry snow-covered glacier, wet snow-
covered glacier and rock-covered glacier on the north slope of
Mount Everest can be successfully identified and mapped from
SIR-C images.
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18. Snowmelt runoff
 Thickness of polar ice sheets (no liquid water present) can
be determined using conventional air-borne radar.
 Combination of SAR with a co-registered high-resolution
DEM (TOPSAR) provides a promising tool for measuring
glacier change in three dimensions.
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19. PROSPECTS OF RS OF GLACIOLOGY
 Launch of NASA’s Earth Observatory Satellites (EOS) Terra
 Enrich availability of quality RS data for studying glaciers from
space.
 Satellite collect data on global scale in 14 spectral bands.
 EOS Terra spacecraft carries a payload of 5 state-of-the-art
sensors
 One of which is Advanced Spaceborne Thermal Emission and
Reflection Radiometer (ASTER).
 This sensor collects data at a spatial resolution of 15 m in the
VNIR spectrum.
 Such high spatial resolution and near-global coverage will
enable ASTER to become a vital information source for
monitoring and mapping of the spatial extent, velocity fields
and other parameters of glaciers around the world.
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ASTER instrument characteristics

21. CONCLUSION
 Aerial photographs used mainly for highly accurate
mapping of glaciers and acquiring detailed glacial
parameters.
 Radar SAR images provide depth information, but are
inadequate for measuring glacier mass balance within a
glacial year alone.
 Integration RS imagery with GIS and GPS make glaciology
more dynamic, analytical, global, exploratory and
predictive.
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22. REFERENCES
 Jay Gaoa and Yansui Liub (2001). Applications of remote
sensing, GIS and GPS in glaciology: a review, Progress in
Physical Geography 25,4 (2001) pp. 520–540.
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23. THANK YOU
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