Jökull - 01.01.2013, Blaðsíða 85

Sensitivity of Icelandic river basins to recent climate variations
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SWE for VHM−96
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Snowmelt for VHM−96
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Glacier melt for VHM−96
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Glacier melt for VHM−96
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Rain for VHM−96
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Rain for VHM−96
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S O N D J F M A M J J A
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Streamflow for VHM−96
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S O N D J F M A M J J A
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Dry
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p<0.1
p>=0.1
Streamflow for VHM−96
Figure 6. River catchment VHM-96, see caption of Figure 5 for explanation. – Vatnasvið VHM-96. Sjá
skýringar við mynd 5.
years and the summer recession period was length-
ened, leading to a significant decrease of summer dis-
charge. Similar results were observed for the partly-
glacierized catchments until early summer. However,
for these catchments, mid- and late summer flows
were similar in warm and cold years, because the in-
creased glacial melt compensated for a reduction of
snowmelt runoff originating in the glacier-free part
of the catchments. For non-glacierized catchments,
the timing of the annual monthly flow peak corre-
sponded quite well with the timing of the snowmelt
peak, between May and June and was shifted ear-
lier accordingly in warm years compared to cold
years. The change in relative contribution between
snow and glacier melt led to a shift forward in time
of the flow peak timing in warm years for three of
the partly-glacierized catchments. For the two catch-
ments with large groundwater aquifers (VHM-64 and
VHM-66) the flow peak shifted earlier in warm years.
Annual precipitation variations between wet and dry
JÖKULL No. 63, 2013 85