The measurements are carried out at four elevation levels (10 m, 48 m, 82 m, 115 m) on a 117 m tall, free-standing TV/radio transmitter tower owned by Antenna Hungaria Corp. The tower is located in a flat region of western Hungary (46° 57'N, 16° 39'E), at an altitude of 248 m above sea level. The tower is surrounded by agricultural fields (mostly crops and fodder of annually changing types) and forest patches. The distribution of vegetation types (60% arable land, 30% forest and woodland, 10% other [vineyard, settlements, etc.]) within 10 km of the tower is not greatly different from the average for the Western Hungarian Landscape Unit (7300 km2) or the whole country (93000 km2) (85% of the area is cultivated, 77% of which is agricultural and 23% is forest). The soil type in the region of the tower is Lessivated brown forest soil (Alfisol, according to USDA system). These soils have clay migration and moderate acidity as well as the more widespread humification, leaching and clay formation. The upper layer is generally 10-20 cm thick, and its organic matter content is 5-8%.
Human habitations within 10 km of the tower are only small villages (100-400 inhabitants). The nearest village is Hegyhatsal (170 inhabitants) about 1 km to the northwest. There is no notable industrial activity in this dominantly agricultural region. Local roads have mostly low levels of traffic. One of the few main roads of the region, which carries 3600 vehicles per day on average, passes approximately 400 m to the southwest of the tower.
Measurements of CO2 mixing ratio profiles, temperature, humidity and wind profiles began in September 1994. CO2 vertical flux measurements (82 m) began in April 1997. The tower is also a NOAA/CMDL global air sampling network site (site code: HUN). More details on the site and instrumentation can be found in Haszpra et al. (2001) and at http://nimbus.elte.hu/hhs/.
Haszpra, L., Barcza, Z., Bakwin, P. S., Berger, B. W., Davis, K. J., Weidinger, T., 2001: Measuring system for the long-term monitoring of biosphere/atmosphere exchange of carbon dioxide. J. of Geophysical Research 106D, 3057-3070.