A comparison of the temperature climate at twourban sites in Uppsala

Sammanfattning: Meteorological data from two observation sites in Uppsala, the Observatory Park (Op) andthe Geocentre (Gc), during the period January 1998 to September 2000, have been used tocheck the differences in the temperature climate at the two places. Since Op is situatedcloser to the city centre than Gc the site is thought to be more affected by the so calledurban heat island effect. Dependence on different meteorological parameters, time of theday and time of the year, has been investigated and different methods to correct thetemperature for the inhomogeneity that was introduced when the observation site wasmoved from the Observatory Park to the Geocentre. From the different methods investigated it is shown that to correct the temperaturesmeasured at the Geocentre to make them represent the conditions at the Observatory Parka division according to wind speed, wind direction, cloudiness and time of the year wasshown to be the most reliable method. But if it had been possible to divide the material alsointo hours of the day, this would probably have increased the reliability of the correction.For practical purposes a correction simply based on the monthly mean differences betweenthe two sites is probably accurate enough, as the most important factor is the annual cycle inthe temperature difference between the two urban sites.