Jökull - 01.01.2012, Page 95

Mass and volume changes of Langjökull ice cap, Iceland, ∼1890 to 2009
Figure 15. a) Ice volume (see Table 2). b) Mass balance of Langjökull deduced from available DEMs (green)
and in situ observations (black). The dashed line is calculated assuming the predicted volume for LIAmax and
the 1937 volume of the ice cap. c-d) Annual temperature and precipitation, respectively, at Hveravellir (black)
in mid-central Iceland and Stykkishólmur (red) in west-Iceland; location in Figure 1. The vertical line shows the
year 1890 (appr. LIAmax). (The precipitation and temperature trends shown are from 11 year running averages
with triangular weight, 5 year filter). – Langjökull: Rúmmál jökulíss (a), meðalafkoma (b) á ýmsum tímabilum
frá lokum litlu ísaldar til nútíðar metin út frá mismuni yfirborðskorta og afkomumælingum, ásamt hita- (c) og
úrkomumælingum (d) í Stykkishólmi (rautt) og á Hveravöllum (svart).
Table 3. Average specific net balance (bn), at Langjökull, estimated from i) the mean difference between avail-
able elevation maps (dDEM) and ii) the surface mass balance in Table 1 (SMB). b-c) Corresponding temperature
(T ) and precipitation (P ) at Hv and St, averaged over the same time intervals as bn. Locations are in Figure
1. – Meðalafkoma Langjökuls, 1937 til 2009, metin út frá mismuni hæðarkorta og afkomumælingum á jökli.
Einnig er sýndur meðalhiti og úrkoma í Stykkishólmi og á Hveravöllum á sama tímabil.
Time interval (a) (b) Hv: Hveravellir (c) St: Stykkishólmur
bn (mwe yr−1 ) T (◦C) P (m) T (◦C) P (m)
August 1937 – August 1945 (dDEM) -1.56 ± 0.50 - - 4.29 0.74
August 1945 – August 1986 (dDEM) -0.31 ± 0.10 - - 3.71 0.69
August 1986 – September 1997 (dDEM) -0.21 ± 0.20 -0.70 0.72 3.88 0.79
September 1997 – August 2004 (dDEM) -1.32 ± 0.20 0.14 0.77 4.37 0.63
September 1997 – August 2004 (SMB) -1.36 ± 0.20 0.14 0.77 4.37 0.63
September 1997 – August 2009 (SMB) -1.26 ± 0.15 0.21 0.80 4.53 0.72
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