the surface of ice. The snow cover on the ice dis-
appears gradually, and water begins to collect on the
ice. This gradually eats away the ice surface and
makes it porous and fragile. Finally, water starts
penetrating the ice, which at this stage hardly bears
the weight of a man. Determination of the extent of
melting is not really an impossible task if use is made
of the most recent inventions in the sphere of photo-
graphy.
By way of summary, it may be said that aerial photo-
graphy has contributed much to ice research in the
Baltic area also. Its future developments will doubt-
less yield new results and open up new fields for
study.
GLACIER INVENTORY FROM
AIR PHOTOGRAPHS
by Valter Schytt
Institute of Geography, Stockholm University,
Stockholm, Sweden.
ABSTRACT
From the mountains in Swedish Lapland only old and
not quite satisfactory maps are available. Previous
inventories of Swedish glaciers have therefore become
rather inaccurate. In 1959 a complete coverage of air
photographs became available and the author has made
use of this material for studying the regional distri-
bution as well as the orientation of Swedish glaciers.
A glacier map at a scale of 1:500 000 is presented. A
total of 237 glaciers has been identified. They cover
a total area of 310 km“. A detailed study of the
glacier orientation shows that about 80 per cent of all
Swedish glaciers (both according to number and to area)
are located in the sector N-NE-E, i.e. they are leeward
accumulations caused by the prevailing westerly and
southwesterly storm winds.
Sur les montagnes de la Laponie suedoise il n’y a
que des cartes vieilles et peu satisfaisantes. Pour
cette raison les inventaires précedents des glaciers
suédois ont été assez inexacts. En 1959 des photo-
graphies aériennes couvrant complètement cette région
ont été disponibles et l'auteur & employé ce matériel
afin d'étudier la distribution régionale aussi bien que
l’orientation des glaciers suédois. Une carte sur les
glaciers sur une échelle de 1:500.000 a été présentée.
Une quantité totale de 237 glaciers a été identifiée.
Ils couvrent une superficie totale de 310 km^. Une
étude détaillée de l’orientation des glaciers montre
qu'environ 80 $ de tous les glaciers suédois (selon la
quantité aussi bien que la superficie) sont placés dans
le secteur de N-NE-E, cela veut dire qu'ils sont des
&ccumulations cÓté sous le vent, causées par des coups
de vent d'ouest et de sud-ouest.
Aerial photography has become a valuable tool for
glaciologists whether they work with temperate or polar
glaciers, on problems related to glacier movement,
glacier regime, size variations or almost anything of
glaciological Interest. For polar expeditions a good
photographic coverage helps the glaciologist to extend
his direct ground observations to much larger areas and
it thus enables him to draw more far-reaching and better
founded conclusions. From drainage features on the
photograph the trained glaciologist can obtain informa-
tion about temperature conditions in the ice and about
the position of the accumulation limit; the existence
of moraine features or lichen-free zones tell their
References:
Betin, B. B., Shadrinkski, S.V., Uralov, N.S., 1959:
Novie metodi morski ledbyl avianabludeni. Trudi
gosudarstvenovo okeanografizeskovo instituta, Nr 37.
Leningard.
Budel, Julius, 1943: Das Luftbild im Dienste der
Eisforschung und Eiserkundung. Zeitschrift der
Gesellschaft fur Erdkund zu Berlin. Heft 7/10. Berlin.
Palosuo, Erkki, 1953: A Treatise on Severe Ice Conditions
in the Central Baltic. Merentutkimuslaitoksen julkaisu
nr 156. Helsinki.
(Rodhe, Bertil,) 1959: The Baltic Ice Code. Sveriges
Meteorologiska och Hydrologiska Institutets
Meddelanden, Serie E nr 10. Stockholm.
Story about the glacial-history; repeated photography
of calving glaciers or ice shelves seems to be the only
practicable way of getting a quantitative measure of
this type of ice wastage.
There are thus numerous problems which can be tackled
only if air photographs are available and one such prob-
lem will be described here.
General inventory of Swedish glaciers.
A quite satisfactory inventory of all Swedish
glaciers has never been carried out because of the lack
of good high mountain topographic maps. The maps avail-
able were prepared around 1880 and 1890, and even though
their quality must be considered as excellent if the
large area, the short time and the difficult working
conditions are taken into account, the deviations be-
tween maps and nature are sometimes considerable.
When it comes to glaciers the maps are of course even
less reliable than they are for the hydrographical and
the main topographical features; several glaciers have
never been plotted as such, several snow fields or
lakes have been plotted as glaciers.
However, during 1959 a good coverage of air photo-
graphs (exposed in 1958) has become available and it is
now possible to make a careful study of glaciers in
various mountain regions as well as of their areal ex-
tent, their orientation, thelr moraine features and
their retreat.
For the present study the author has made a rather
preliminary inventory and used the following simple
procedure:
1/ Vertical air photographs at an approximate scale of
1:65000, or occasionally 1:30000, have been studied
under a stereoscope, and as soon as a snow or ice
feature has been identified as a glacier it has been
plotted on tracing paper straight from one photograph
only. Together with the glaciers all rivers and lakes
have also been plotted on the paper but seldom any
other topographic features.
1) The hitherto most comprehensive one was published
in 1910 - Die Gletscher Schwedens im Jahre 1908.
Sveriges Geologiska Undersokning. Ser.C&. No 5. It
contains a glacier map of all Sweden and several very
valuable papers on different glaciers and glacierized
regions.
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