glacier definition

[V.Konovalov]

Hi All and Bruce personally as initiator of late discussion,

1. I believe that before glacier's bounding all analysts should
understand and  agree that the reliability of the final result depends
not only from correct definition of "glacier" but also from many
objective and subjective reasons.
Objective reasons.
Quality of satellite image (e.g., number of spectral bands) and its  resolution,
proper time of scanning glacier surface from space, availability  and
application additional information like large scale maps, photos of
glaciers taken from ground or from air board, using "Google Earth" or
NASA  "World Wind" computer facilities, availability of modern
software packages, comprehensive and detail guide on using satellite
scenes for glaciers bounding. This list could be continued and only
God may provide all these reasons together in one hands. Thus the
final result of outlining and digitizing could not be ideal despite of
excellent definition.
Subjective reasons.
Level of analyst's special experience as well in field glaciological works
as in using GIS software, interest of analyst to come to the best result, etc.

2. I think that the GLIMS Database on Glaciers should have strong connection
and consistency to the previous glacier inventories. It is rather difficult
to provide because we have no cartography schemes for past glacier boundaries.
Nevertheless we must do it in order to save continuity of historical ranges
despite of the source of additional errors exists here.

3. The proposed or former glacier definition based mainly on experience of
field glaciological works and assurance that someone can recognize ever on
satellite image such features like:
- connection type of snowfields to the glacier body in its accumulation area,
- dead and active debris covered ice,
- exact boundaries of marginal and terminal moraines.
Actually it is rather doubtful and depends from objective and subjective reasons (see above).
Thus definition of glacier should reflect specific details of recognition and digitizing
its contour on satellite images. Glacier contour obtained from field works or after using
airphoto topography will be different from the same one obtained after processing of
satellite scenes. The difference will arise as a rule in accumulation area and at the
moraine covered areas. Proposed definition do not consider specific features of glacier
bounding on different satellite scenes.

Finally I suggest to elaborate the following paragraph "Definition of
glacier boundaries, their  recognition and digitizing on satellite
scenes".
Thank you for attention.
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Best regards,
Vladimir Konovalov
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mailto:vladgeo_exp at mtu-net.ru