Near surface climate in an urban vegetated park and its surroundings

Near surface climate was observed through temperature profiling from the surface to 2.47 m height in an urban vegetated park and its surroundings in central Stockholm, Sweden. Measurements were conducted during three summer days by mobile traverses. Air temperature differences between the built-up area and the park were in the range of 0.5-0.8 degrees C during the day and reached a maximum of 2 degrees C at sunset. The thermal stratification of the air was mainly stable in the park and unstable in the built-up area. Inverse air temperature profiles in the park were less stable in open than in shady areas, and close to neutral at midday. The most unstable air was found in the north-south orientated canyons in the early afternoon. Possible heat advection from the surroundings, and thus uncoupling between the surface and the air, was identified through temperature gradients pointing at different directions within the 2.47 m profile. Examples at midday indicated that warm air advected as far as 150 m into the park. [PUBLICATION ABSTRACT]