Jökull - 01.12.1991, Side 95

jökull allir í Vatnajökli og Reykjafjarðarjökull í
Drangajökli.
Flestir jöklar landsins sýna þess merki að þeir hafi
tekið eftir að veðurfar kólnaði til muna um miðjan 7.
áratuginn. Þeir hætta að hopa og margir hverjir fara
að ganga fram þegar um 1970. Sólheimajökull er gott
dæmi um þetta og er því birt hér línurit af breytingum
hans í 60 ár.
Aðrir jöklar, einkum hinir breiðu, voldugu skrið-
jöklar Vatnajökuls, halda áfram að hopa eins og
ekkert hafi í skorist enda eiga þeir það til flestir eða
allir að hlaupa fram með mislöngu árabili án þess að
veðurfar gefi tilefni hverju sinni.
Drangajökull hefur nokkra sérstöðu meðal ís-
lenskra jökla. Kólnun undanfarinna áratuga virðist
ekki hafa áhrif á hann. Má því ætla að loftslagsbreyt-
ingin um 1930 hafi verið hlutfallslega meiri þar en
annars staðar á landinu.
Heldur væri stuttaralegt að afgreiða jökla-
breytingar á íslandi undanfarna 3 áratugi á þann hátt
sem hér er gert. Þess vegna er í ráði að skrifa um þær
greinar, sem birtast munu í Jökli á næstu árum.
Abstract
GLACIER VARIATIONS
1930-1960, 1960-1990 and 1989-1990
Glacier variations were recorded at 41 locations, 10
tongues showed advance, 5 were stationary and 26
retreated. Five of the visited stations were not
accessible because of snow and lagoons.
This is the final year of the second 30-year period
of measurements of glacier variations in Iceland.
During the period 1930-1960 all measured glacier
snouts experienced an overall retreat without
exception. This showes the magnitude of the changes
that took place in the climate in Iceland at the
beginning of this period.
In the period 1960-1990 there exist more or less
complete records from 34 glacier snouts that are
considered individual glaciers or separate outlet
glacier from an ice cap. 12 of those advanced while
22 retreated. The retreat amounted to more than one
kilometer at 4 locations. The glacier variations reflect
the cooling of the climate in the mid-sixties. Many
glaciers not only stopped retreating, but several
advanced considerably around 1970 and onward.
This is most obvious for the outlet glaciers of
Öræfajökull, the south-east part of Vatnajökull,
Sólheimajökull (fig. 1), Gígjökull, Gljúfurárjökull
and Snæfellsjökull. These glaciers have a steep
topographic gradient. The broad big outlet glaciers of
Vatnajökull seem less affected by such short(!)
periods of climate variation. They tend to be surging
glaciers too.
Drangajökull on the NW peninsula seems to have
experienced a greater change of climate around 1930
than other Icelandic glaciers. It keeps on retreating
almost at full pace all the period from 1930 to 1990.
JÖKULL,No. 41, 1991 93