Jökull - 01.12.1970, Blaðsíða 54

Fig. 2. An oblique photograph of Breidamerk-
urjökull on September 6, 1967. The bridge on
Jökulsá and Breidamerkurlón are in the fore-
ground, but the nunataks in Breidamerkur-
jökull appear in the background. They are:
Mávabyggdir to the left and Braedrasker and
Kárasker farther downhill. The next four aretes
are the Esjufjöll ranges, they are counted from
the left, Vesturbjörg, Skálabjörg, Esjubjörg and
Austurbjörg. The western slopes of Vedurár-
dalsfjöll can be seen below the wing of the
aeroplane. Photo: G. Sigbjarnarson.
Mynd 2. Flugmynd af Breiðamerkurjökli þ. 6.
september 1967. ]ökulsárbrúin og Breiðamerh-
urlón eru fremst á myndinni. Jökulskerin í
Breiðamerkurjökli sjást vel, en þau eru talin
frá vinstri: Mávabyggðir og þar fyrir neðan
Brœðrasker og Kárasker, siðan koma Esjufjalla-
hryggirnir fjórir, Vesturbjörg, Skálabjörg, Esju-
björg og Austurbjörg. Undir flugvélarvœngnum
sést í Veðurárdalsfjöll.
MEASUREMENTS
ON BREIDAMERKURJÖKULL
S. Thorarinsson (1943) concludes that Breida-
merkurjökull reached its greatest extent in
1894. Since then it has been retreating conti-
nuously with the exception of singular years
marked by some glacial advance. The year 1894
will therefore be used as a starting point for
the calculations of the glacial recession describ-
ed in this paper. These calculations are based
on the following data.
The maps of Geodaeiic Institute, Copenhag-
en (Fig. 1). The lower part of Breidamerkur-
jökull was rnapped at a scale of 1:50,000 ac-
cording to measurements carried out in the
years 1903 and 1904 (map sheets 87 SE, 87 NE,
97 SW and 97 NW), but the first mapping of
the upper part of the glacier was done with
the aid of aerial photographs dating from the
years 1937 and 1938 at the scale of 1:100,000
(map sheets 86 and 96). The contour intervals
on these maps are 20 m. The maps are based
on observations 34 years apart and their use
íor calculations must be restricted to the glacier
margins and a comparatively short distance up
the glacier.
The maps of the U.S. Army Map Service
(Map sheets 6019 I, 6019 II, 6019 III, 6019 IV,
6020 II and 6020 III). These maps are drawn
by photogrammetric methods from aerial photo-
graphs taken during the years 1945—46. The
photographs covering the glacier margin and a
greater part of the glacier itself were taken in
August 1945. These maps are reliable in all
broad outlines. They are at a scale of 1:50,000
with 20 m contour intervals.
The map of the University of Glasgow. The
Department of Geography of the University
of Glasgow has recently finished preparing a
map of the lowest part of Breidamerkurjökull
drawn by photogrammetric method using aerial
photographs from the year 1965 (Price 1968).
Fig. 3. On Breidamerkurjökull, July 26, 1968.
A view towards the east from SW of Skálabjörg.
The black line on the glacier is the Esjufjöll
medial moraine. In the background are Sudur-
sveit mountains, where Thverártindsegg is the
highest peak. Photo: G. Sigbjarnarson.
Mynd 3. Horft austur til Suðursveitarfjalla af
Breiðamerkurjökli SV við Skálabjörg. Esjufjalla-
röndin sést sem dökk lina þvert yfir jökulinn
á myndinni. Þverártindsegg er hæsta fjallið i
Suðursveitarfjöllum.
52 JÖKULL 20. ÁR