Jökull - 01.01.2013, Blaðsíða 95

Mass balance of Mýrdalsjökull ice cap
Figure 2. (a) Density profiles through the 2010 winter layer at points M1, M2 and M3. (b) Mean annual layer
density (open circles) and mean for 2007–2012 (filled circles) for M1, M2 and M3 as a function of elevation,
as well as mean densities on a transect on the northern part of the Hofsjökull ice cap in central Iceland (grey),
for the same years. (c) Temperature profiles through the 2011 winter layer at M1 (red) and on southwest Hofs-
jökull (grey). (d) Mean density of annual layer (2007–2012) vs. day of year measured (JD), for M1, M2 and
M3 (green), and from 1250–1600 m a.s.l. on Hofsjökull northern transect (grey; rectangles for single year val-
ues). – (a) Eðlismassi vetrarlagsins 2010 m.v. dýpi í M1, M2 og M3. (b) Meðaleðlismassi árlags (hringir) og
meðaltal 2007–2012 (fylltir hringir) í M1, M2 og M3 sem fall af hæð mælistaðar. Til samanburðar er sýndur
meðaleðlismassi í sniði á norðurhluta Hofsjökuls (grátt) fyrir sömu ár. (c) Hitastig vetrarlagsins 2011 m.v. dýpi
í M1 (rautt), og á suðvestanverðum Hofsjökli (grátt). (d) Meðaleðlismassi árlags (2007–2012) m.v. dag árs er
mælt var, í M1, M2 og M3 (grænt) og úr 1250–1600 m hæð á norðanverðum Hofsjökli (grátt; ferningar fyrir
stök ár).
fication during spring warming has occurred at the
lowest point, M1, where the mean density of the an-
nual layer was 610 kgm−3. The data from Mýrdals-
jökull are depicted in Figure 2b, in comparison with
typical spring values of density measured on Hofs-
jökull. The Hofsjökull transect covers an elevation
interval of 800 m and runs through both the accumu-
lation and ablation areas on the northern part of that
ice cap, whereas the Mýrdalsjökull data are confined
to a narrow elevation interval within the accumulation
area (elevation interval 1345–1500 m a.s.l.). We ob-
serve 10–20% higher densities on Mýrdalsjökull than
JÖKULL No. 63, 2013 95