Jökull - 01.12.1991, Page 13

Fig. 13 : Distribution of correlation
coefficients of the temperature of July
between Stórinúpur/Hæll as a basic
station and other stations.
Mynd 13: Fylgni júlíhita á
Stóranúpi/Hæli við aðrar veðurstöðvar.
The conclusion is that temperature variations from
year to year in summer are not in phase for the coun-
try as a whole. There is a little relation between sum-
mer temperature in different regions. A warm sum-
mer in one part of the country can occur with a cool
summer in the opposite part.
Correlation coefficients between stations in south-
western and northeastem or eastern Iceland are, with
few exceptions, lowest in July, often in the interval of
0.00-0.20. Values for the same month between sta-
tions in the northwestern part of the country and the
southeastern one are 0.23-0.47. Examples in
Figs.12-13 show the distribution of July temperature
correlation.
In Fig.12 Hallormsstaður is the basic station and
the distribution of the correlation coefficient of the
temperature of July with other stations is shown. In
this case it is obvious that temperature variations are
in phase only in northeastern Iceland with coeffi-
cients >0.80 which decrease gradually towards south
and west.
In Fig.13 a contrast example with Stórinúpur/Hæll
in southern Iceland as a basic station is shown. The
correlation coefficients are >0.80 in the southwestern
part next to the basic station and decreasing towards
north and east.
The conclusion of these two examples is that the
temperature of July in the southwestern part of
Iceland and the northeastern and eastern on the other
hand is almost completely uncorrelated. This is also
valid for the other summer months June and August.
It would be of interest to compare the temperature
variations in July within and between these opposite
regions, having in mind the however unlikely possi-
bility that one weather type is predominant for the
month as a whole. This will be attempted indirectly
as follows.
The author has earlier presented a classification of
main weather types in Iceland (Einarsson, 1976,
1984), with the intention of describing for each type
the main characteristics of the weather. Although
they are, in a subjective way, based on the author's
experience, investigations have shown that each type
shows distinct characteristics different from the other
types (Einarsson, 1983).
For the 5-year period 1970-1974 days from 09h
GMT to the same time next day matching one of the
weather types have been selected, originally for other
purposes. These types are (Fig. 14): a) southeastern
(SE), b) southwestern or western (SW), c) southern
with warm air mass (S), d) eastern (E), e) northeast-
ern (NE), f) northern (N).
Maps showing for each weather type the distribu-
tion of minimum and maximum temperatures in
JÖKULL, No. 41, 1991 11