CH-BaK is an urban ecosystem station located in the city center of Basel, Switzerland. The station is situated on the flat roof top of the 20 m high building (260 m a.s.l.), and the site is characterized as a 'compact mid-rise' area (LCZ 2) according to the local climate zone classification. The neighborhood of the site is mainly characterized by the inner ring street Klingelbergstrasse to the east with heavy traffic (15?000 vehicles per workday), and by residential buildings enclosing green backyards to the west. Furthermore, some tall university buildings are located approximately 250 m to the north and the northeast of the site. Within a 400 m radius circle around the tower, 38% of the surface is covered by buildings (mean height 17 m), 20% is paved, 29% is covered by vegetation (14% trees, 15% grass/soil) and 13% are roads. The emissions from the eastern sector are high and have a significant contribution from traffic, while the fluxes from the western mainly residential area are lower and dominated by heating in the winter season.
