Jökull - 01.01.2013, Page 86

P. Crochet
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m
m
/d
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20
0
60
0
10
00 Cold
Wam
71−00 ●
p<0.05
p<0.1
p>=0.1
SWE for VHM−66
●
m
m
/d
20
0
60
0
10
00 Wet
Dry
71−00 ●
p<0.05
p<0.1
p>=0.1
SWE for VHM−66
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m
m
/d
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0
1
2
3
4
5
6
Cold
Wam
71−00 ●
p<0.05
p<0.1
p>=0.1
Snowmelt for VHM−66
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m
m
/d
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0
1
2
3
4
5
6
Wet
Dry
71−00 ●
p<0.05
p<0.1
p>=0.1
Snowmelt for VHM−66
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m
m
/d
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0
1
2
3
4
5
6
Cold
Wam
71−00 ●
p<0.05
p<0.1
p>=0.1
Glacier melt for VHM−66
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m
m
/d
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0
1
2
3
4
5
6
Wet
Dry
71−00 ●
p<0.05
p<0.1
p>=0.1
Glacier melt for VHM−66
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m
m
/d
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●
1
2
3
4
5
6
Cold
Wam
71−00 ●
p<0.05
p<0.1
p>=0.1
Rain for VHM−66
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m
m
/d
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●
● ●
1
2
3
4
5
6
Wet
Dry
71−00 ●
p<0.05
p<0.1
p>=0.1
Rain for VHM−66
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m
³/
s ●
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●
S O N D J F M A M J J A
60
80
10
0
12
0
Cold
Wam
71−00 ●
p<0.05
p<0.1
p>=0.1
Streamflow for VHM−66
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m
³/
s
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●
S O N D J F M A M J J A
60
80
10
0
12
0
Wet
Dry
71−00 ●
p<0.05
p<0.1
p>=0.1
Streamflow for VHM−66
Figure 7. River catchment VHM-66, see caption of Figure 5 for explanation. – Vatnasvið VHM-66. Sjá
skýringar við mynd 5.
years had an impact on monthly streamflow, which
increased significantly in wet years during a period
that depended on catchment type and location. How-
ever, no systematic timing changes were detected in
hydrological events such as the annual flow peak date,
except for two catchments (VHM-10 and VHM-19)
where the annual maximum monthly streamflow was
shifted 1 month later in wet years and for catchment
VHM-66 where it occurred earlier.
Relation with changes in atmospheric circulation
Interannual precipitation and temperature variations
and their impact on hydrology can be caused by
changes in atmospheric circulation patterns. The
North Atlantic Oscillation (NAO) is a major source
of interannual variability in the atmospheric circula-
tion over the middle and high latitudes of the North-
ern Hemisphere (NH) and exerts an influence on win-
tertime temperature and precipitation across much
of the NH (Hurrell, 1995; Hurrell et al., 2003).
86 JÖKULL No. 63, 2013