Oslo UHI experiment, 25. January 2007

Bogstadvannet at the southern end of Sørkedalen, northwestern Oslo, showing the general weather situation 25. January 2007.

The general weather situation, measurement equipment and measurement route

The weather was cold, almost overcast, with light southerly to southwesterly winds, about 1 m/s. A thermistor mounted inside a radiation shield was attached to the roof of a car (c. 1.5 m above terrain), and temperatures were logges at 5 sec. intervals. The time given in the diagrams below are according to normal winter zonal time. The measurements were carried out for two routes, passing through the city, but beginning and ending outside the city in the open, rural landscape:

1. Starting in upper Sørkedalen northwest of Oslo, driving through southern Oslo, and ending northeast of Oslo.

2. The opposite route, but passing through northern Oslo, thereby passing within 100 m of the meteorological observation site of the Norwegian Meteorological Institute.

The geographical location of the two measurement routes is shown in the map below. Oslo is the capital of Norway, and presently has a total population of 548,617 (January 1, 2007). By international standards, it is a relatively small city. 

Map showing location of the two measurement runs. RUN 1 is the southern route from west towards east, while RUN 2 is the northern route from east towards west. The map measures 30 km from west to east. The altitude ranges from about 150 and 180 m asl., at the western and eastern endpoint, respectively, and about 5 m asl. near the coast.

Results

Run 1. Starting in open landscape in upper Sørkedalen, passing through southern Oslo, and ending in open landscape northeast of Oslo.

Run 2. Starting in open landscape northeast of Oslo, passing through northern Oslo, and ending in open landscape at the head of Sørkedalen.