Geoscience Reference
In-Depth Information
Table 2.7
Climatological data from the normal period 1981
-
2010 for Jokioinen (60
°
48
′
N23
°
30
′
E)
and Utsjoki Kevo (69
°
45
′
N27
°
00
′
E)
Jokioinen
Tempe
rature
(
Precipitation
(mm)
Incoming solar
radiation
(W m
−
2
)
Relative
humidity
(%)
Cloudiness
(1/8)
Wind
m/s
direction
°
C)
January
−
5.6
46
11
89
6.4
3.6
165
February
−
6.3
32
38
87
6.0
3.5
171
March
−
2.4
32
87
82
5.5
3.5
168
April
3.5
30
152
72
5.6
3.5
153
May
9.8
41
208
65
5.1
3.5
163
June
14.0
63
225
68
4.9
3.3
235
July
16.7
75
218
71
5.3
3.1
201
August
15.0
80
162
77
5.6
3.1
150
September
9.9
58
97
83
5.9
3.3
194
October
4.9
66
41
88
6.2
3.5
194
November
−
0.2
57
13
91
6.7
3.7
164
December
−
3.9
47
6
91
6.6
3.7
173
Utsjoki
Temperature
(
°
C)
Precipitation
(mm)
Incoming solar
radiation (W m
−
2
)
Relative
humidity (%)
Wind
m/s
direction
January
-
14.0
27
1
85
2.8
165
February
-
12.8
24
15
83
2.9
171
March
-
8.2
21
66
81
3.0
168
April
-
2.5
25
146
76
2.9
153
May
3.7
27
181
72
3.0
163
June
9.6
50
195
68
3.2
235
July
13.1
72
170
74
2.9
201
August
10.7
57
116
80
2.6
150
September
5.7
38
61
85
2.6
194
October
-
0.5
39
29
88
2.7
194
November
-
8.3
28
1
88
2.6
164
December
12.3
25
0
86
3.7
173
-
The data are from Pirinen et al. (2012) expect cloudiness is from 1971
-
1980 (FMI 1982)
where q
s
and e
s
are the saturation levels of speci
c humidity and water vapour pressure,
respectively. Annual variations in relative humidity are usually small, but the absolute
humidity follows largely the air temperature.
Solar radiation has a strong annual cycle in high-latitude lakes, so that the radiation
balance is switched from positive to negative for the cold season. It re
ects the presence of
polar summer and polar winter in the north. Over lakes, the sensible and latent heat losses
to the atmosphere are strong in fall and winter as long as the surface is ice-free but go
down after the ice has formed. Transport of warm air from lower latitudes by intensive
cyclone activity may delay ice formation. This transport is especially strong for central
and northern Europe since the North Atlantic Current brings warm water and adds heat
into the atmosphere. When the westerlies are strong (positive NAO index), they are able to
transport this oceanic heat to lakes in the European continent.
fl
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