Jökull - 01.01.2019, Page 113

Tussetschläger et al.
Figure 4. Maps from each study area indicate that the likelihood of occurrence of snow patches is quite variable.
a) Almenningar and Úlfsdalir, b) Brimnesdalur, c) Kerling, d) Búrfellsdalur, and e) Sakka. The hillshade is de-
rived from the DEM (25 m resolution) provided by LMI. Darker coloured areas represent increased likelihood
of snow patch occurrence. – Kortin sýna að talsvert mismunandi líkur eru á að fannir varðveitist á svæðunum.
and are also mapped in each time period of the PSP
distributions, except in the year 2017 when only small
snow patches occur. In Búrfellsdalur (Figure 4d) the
snow patches on the west side of the valley have very
high occurrence likelihood as well as the ones in front
of the glacier. Many snow patches in the Búrfellsdalur
area have a similar likelihood to persist or melt dur-
ing summer. In the winters 2015/2016 (662 mm) and
2016/2017 (664 mm) about 13% less winter precipita-
tion was measured than on average during the last four
winters before (2010–2015). This is also reflected in
the snow pattern of the last five years (Appendix - Ta-
ble A1 and Figure A1). In the Sakka area (Figure
4e) many snow patches have a moderate likelihood
(50%) of occurrence. The highest peaks are around
950 m a.s.l. but the main area where snow patches are
located is at elevations between 600 and 750 m a.s.l.
Only few snow patches occur with a high probability,
e.g. close to the small glacier in the south of the area.
Comparison and Validation of the Perennial Snow
Patches
In the following sections different datasets are used to
compare and validate the PSPs classification. Where
available, aerial images, orthophotos and field work
photos are included as well as data from weather sta-
tions.
For all study areas, except Almenningar, aerial
and satellite images are from the same years and
therefore used to compare the results. In Kerling the
112 JÖKULL No. 69, 2019