Jökull - 01.01.2020, Síða 76

Reviewed research article
Little Ice Age advance of Kvískerjajöklar, Öræfajökull, Iceland.
A contribution to the assessment of glacier variations in Iceland
since the late 18th century
Snævarr Guðmundsson1∗ and Helgi Björnsson2
1South East Iceland Nature Research Center, Litlubrú 2, Höfn í Hornafirði, Iceland
2Institute of Earth Sciences, Science Institute, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland
∗Corresponding author: snaevarr@nattsa.is
https://doi.org/10.33799/jokull2020.70.073
Abstract — We describe the changes of the Kvískerjajöklar outlet glaciers in SE Iceland (presently ranging
600–1600 m a.s.l.), from their Little Ice Age maximum (LIAmax) to the present. We assume that glacier extent
of the late 19th century approximately describes LIAmax although the glaciers already reached their peak
extent in the 18th century. The former glacier margins were delineated from moraines, historical descriptions,
topographical maps, aerial and oblique photographs, Landsat images and a lidar DEM. Along the previous
glacier margins, elevation differences with respect to the lidar DEM of 2011 were estimated and contour maps
of the glacier drawn at selected dates, maintaining the shape of the glacier surface as available maps. During
the period ∼1890 to 2011, the outlets lost -0.4 m a−1 water equivalent evenly distributed over their surface and
their area was reduced by 37% (from ∼10 km2 to 6.4 km2, 0.03 km2 a−1, 0.43 km3 water equivalent in total,
i.e. 0.003 km3 w.e. a−1).
INTRODUCTION
The Kvískerjajöklar outlet glaciers (6.4 km2 in 2011)
drain the steep, eastern flanks of Öræfajökull stra-
tovolcano, SE-Vatnajökull ice cap. The outlets are
divided in two segments, the North and South glacier
by a volcanic fissure ridge which can be traced up to
the caldera rim of the volcano (1800 m a.s.l.), con-
taining the prominent nunataks of Hellutindar (1142
m a.s.l.) and Rótarfjallshnúkur (1026 m a.s.l.), Fig-
ure 1. The North glacier was 4.3 km long in 2011,
terminating at 580 m a.s.l. whereas the South glacier
was 2.8 km long, ending at 700 m a.s.l. The estimated
total volume of the glaciers is approximately 2 km3
(Magnússon et al., 2012). Like other outlets of Vatna-
jökull, they have retreated considerably since their
maximum extent during the Little Ice Age (LIAmax).
Most of the larger outlet glaciers in Southeast Ice-
land reached their LIAmax in the 1880s to 1890s,
whereas some of the small and steepest glaciers al-
ready may have reached their outermost position in
the 18th century and thereafter remained close to that
location until the late 19th century. Based on writ-
ten and oral records about marginal moraines of Kví-
skerjajöklar, we contribute to the discussion on of
glacier variations in Iceland since the late 18th cen-
tury to the present.
Synopsis of glaciers and climatic variations during
the Little Ice Age
The climate in Iceland was relatively cold from the
13th century to the 1920s, a period often called the
Little Ice Age (LIA), but was however, interrupted
by frequent warm spells. The account of the climate
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