Lisø PhD Dissertation Manuscript - NTNU

Lisø, K.R./ Building envelope performance in harsh climates: Methods for geographically dependent design
(group C) have a coldest month average between -3ºC and 18°C. Moist mid-latitude
climates with cold winters (group D) have an average temperature above 10°C in
their warmest months, and a coldest month average below -3°C. Polar climates
(group E) are characterized by average temperatures below 10°C in all twelve
months of the year. Most of the country has a moist mid-latitude climate with cold
winters. The extensive coastline does for a large part sort under climate C, while
Svalbard (not on the map), parts of Finnmark County and the mountain areas have a
polar climate.
There are also large differences in the normal annual precipitation in Norway. The
largest normal annual precipitation is found some miles from the coast of Western
Norway. These amounts are also among the highest in Europe. Brekke in Sogn og
Fjordane County has an annual normal precipitation of 3575 mm, and several other
stations in this area follow close behind. Brekke has also the record for one-year
precipitation, with 5596 mm in 1990. The inner part of Østlandet, the Finnmark
Plateau, and some smaller areas near the Swedish border, are all lee areas in relation
to the large weather systems mainly coming from the west. Common for these areas
is the low annual precipitation and that showery precipitation during summer is the
largest contributor. Øygarden at Skjåk (Oppland County, located less than 150 km in
overhead line from Brekke) has the lowest annual normal precipitation with 278 mm.
This is lower than the normal monthly precipitation for the 6 wettest months of
Brekke. However, the lowest recorded precipitation for one year is only 118 mm,
measured at Saltdal (Nordland County) in 1996.
The climate statistics in this section are obtained from www.met.no.
1.3 Climate data and the weather observation network
Climate is usually defined as the long-term average condition of the atmosphere at a
geographical locality, including the normal and extreme deviation from this average
condition. The climate, or “average weather”, can be described in different ways.
The most common way is to define “normal” periods (averages over e.g. the classical
30-year period, as defined by the World Meteorological Organization (WMO)), and
to compare today’s weather and observations with these reference periods. Weather
observations in Norway have not historically been recorded as hourly averages, and
even today this is done at only at a few stations at the largest airports in the country.
Observations are typically done only a maximum of three times a day. There are
about 550 observing stations in the country with manual recordings of precipitation,
and about 150 observing stations for synoptic observations of climate variables such
as temperature, air humidity, wind, atmospheric pressure, clouds and snow depth.
Automated weather stations are becoming increasingly common, and there are now
about 20 automated stations recording hourly temperature, wind and precipitation
amounts.
Synoptic observations from most weather stations in Norway include the 10-minute
average wind speed and direction at the time of observation as well as a numerical
code identifying the state of the weather at the time of the observation. The objective
is to provide the weather situation at a given point of time for a larger geographical
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