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NORDIC LIGHT & COLOUR
29
the colours are subdued, and there is no sparkling, no reflec-
tions and no shadows.
Since the fine artists were convinced about uniqueness of
Nordic light, maybe we may find some objective data that can
support this point of view.
The position of the sun
Let us reflect on one of the most important parameters, which
is the position of the sun on the sky, as is visible in the Nordic
countries. It may be observed that three capitals and other
large towns in northern Europe have latitudes close to 60°,
see table 1.
Even a squat look at the sun diagram for one of those cities,
e.g. Oslo, and the sun diagram for, say, Cairo, will help us find
the most fundamental difference between daylight in the North
and in the South, i.e. the prevailing height of the sun over the
horizon. The sun moves straight up after sunrise in Cairo. In
Oslo the movement is more horizontal; the elevation angle of
the sun increases slowly over many hours and never reaches
the area around the zenith. The highest position of the sun dur-
ing the year in Oslo is 53,53°, the elevation angle at noon at the
equinox is only 30,52°, while the two respective angles for Cairo
are 83,37° and 60,33°.
Timing of the solar elevation angle
Another interesting aspect is connected to time. Since the
position of the sun in Nordic countries is very low, the sun is
near the horizon considerably longer than in countries situated
at lower latitudes as e.g. Cairo, 30°03’N. The very interesting
question is how long can we expect the sun to be e.g. between
0° and 10° above the horizon?
The calculations of the percentage of daytime occurring during
the first part of the year when the elevation angle of the sun is
in intervals - (0° - 10°), (10° - 30°) and (over 30°) - were made
with the help of the Solar Beam software (Solar Beam 2013) for
Trondheim: 63°26’, see figure 6 and 7. The results are present-
ed also in table 2.
Figure 3. The sun diagram for Oslo and Cairo generated in relation to an observer standing at the centre. The horizon is represented by the
largest circle.
Table 1. Latitudes for large Nordic cities situated closely to 60°N.