Jökull - 01.10.1998, Blaðsíða 5

Glacier variations in Iceland 1930-1995
From the database of the Iceland Glaciological Society
Oddur Sigurðsson
National Energy Authority, Hydrological Service
Grensásvegi 9, 108 Reykjavík
Abstract - Observations ofthe advance and retreat ofglaciers in Iceland from 1930 to 1995 are
presented in tables and graphs. The records, which have previously been published in yearly re-
ports in Jökull, have been computerised, checked and corrected and are available on the Internet.
Most ofthe non-surging glaciers retreated strongly during the early halfofthe monitoring period
followed by a readvance or a slowing ofthe retreat after about 1970. Observations of surge-type
glaciers are dominated by the surge events.
INTRODU CTION
In the year 1930, the meteorologist Jón Eyþórsson
began monitoring the advance and retreat of glaciers
in Iceland on a yearly basis (Eyþórsson, 1931). Dur-
ing the 1930s, he started out with 44 different glaciers
and outlet glaciers, some of them measured at up to
five different locations. Of those, 28 are still attended
annually but some have been abandoned at least for
the time being. Thirteen new glacier tongues have
been added in later decades so that monitoring is now
carried out on 41 glaciers or outlet glaciers at 55 loca-
tions. The measurements of each year are reported in
the joumal Jökull and the measurements of the first
10 and 30 years were summarised and interpreted by
Eyþórsson (1942, 1963).
The monitored glaciers are located in different
parts of Iceland and few are accessible by convention-
al roads. Measurements are carried out by lay people
of different occupations, often members of the Ice-
land Glaciological Society. Through the years, most
of them have been farmers. Many of them have car-
ried on for decades. The record holder had in 1995
measured his glaciers for 49 consecutive years not
missing out on a single year!
In the beginning, most of the bench marks estab-
lished at the glacier fronts were cairns of rock, but
gradually they have been substituted by poles of steel
engraved with a number and the emblem of the
Glaciological Society. Measurements are in most
cases made by tape or a string of known length.
Reports were made in a personal letter to the late
Jón Eyþórsson until 1966. These letters are archived
at the Glaciological Society. Since 1967, the surveyor
has filled in a form stating the measured distances to-
gether with a brief description if something unusual
was observed at the site. Since 1964, a subset of the
data has been sent to the World Glacier Monitoring
Service (WGMS) (Permanent Service on the Fluctua-
tions of Glaciers of the IUGG - FAGS ICSU, 1973,
1977, 1985; World Glacier Monitoring Service, 1988,
1993), where it is available in the publications of the
WGMS and electronically.
This paper publishes all the observations since Jón
Eyþórsson's initiation of regular glacier monitoring in
Iceland in the 1930's. The data are compiled from the
original records, the yearly reports in Jökull (Eyþórs-
son/Rist/Sigurðsson, 1951-95) and from Eyþórsson
(1942, 1963). The original reports have been checked
and a few errors and misinterpretations which were
found in the yearly reports have been corrected.
In some cases, the location of glacier termini be-
fore the initiation of regular monitoring has been in-
ferred from maps, aerial photographs or other means
by geologists or other scientists working in the area.
Some such observations from this and the previous
century are included in the data compiled here as in
Eyþórsson (1942,1963). This compilation of such ob-
JOKULL, No. 45, 1998
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