Atmospheric Carbon Dioxide Record from Schauinsland, Germany
Martina Schmidt and Ingeborg Levin
Institut fuer Umweltphysik,
University of Heidelberg,
Period of Record
Air samples are collected from air intake lines. Continuous monitoring of atmospheric CO2 is accomplished by alternating a flowing sample of ambient air with two reference gases of known concentrations. Determinations of CO2 are made using a Siemens ULTRAMAT-3 nondispersive infrared gas analyzer. Before entering the analyzer, all gases are dried by passing them through a glass water vapor trap immersed in a cold alcohol bath. Mixtures of CO2-in-N2 are used for calibration gases. At Schauinsland, CO2-in-air calibration gases were used until September 1, 1991.
Only technically biased values resulting from calibration problems or equipment malfunctions are removed. Daily mean values are calculated from selected half-hourly mean values with relative precisions estimated at ~1 part per million by volume (ppmv). Representative half-hourly CO2 values are given when wind speed exceeds 2.5 m/sec in summer and exceeds 3.5 m/sec in winter. Daily means also include remaining nighttime measurements. Carrier gas corrections have been determined experimentally and applied on the basis of CO2-in-air standards calibrated by Scripps Institution of Oceanography in 1988. More details about the sampling methods and data selection procedures are provided in Grosch et al. (1981), Levin (1991), and Schmidt et al. (1996).
Mountain peak in the Black Forest mountain range,
47°55' N, 7°55' E
Atmospheric CO2 concentrations at Schauinsland rose from ~328 parts per million by volume (ppmv) in 1972 to ~365 ppmv in 1997. This represents a growth rate of approximately 1.5 ppmv per year. The Schauinsland site is considered the least contaminated of the UBA sites. The atmospheric CO2 record from Schauinsland is influenced by photosynthetic depletion but does not exhibit the large seasonal amplitude observed at other UBA monitoring sites. The seasonal amplitude is generally 15-18 ppmv. Minimum atmospheric CO2 mixing ratios at Schauinsland are typically observed in July-September; maximum values, in November-March.
- Grosh, W., W. Fleck, and D. Jost. 1981. The increase of carbon dioxide at rural sites of Germany. Berichte aus dem Meßnetz des Umweltbundesamtes.
- Levin, I. 1991. Der Beitrag der fossilen Energieträger zum CO2-Haushalt über dem europäischen Kontinent. Abschlußbericht zum Forschungsvorhaben FE 104 02627
- Levin, I., R. Graul, and N.B.A. Trivett. 1995. Long-term observations of atmospheric CO2 and carbon isotopes at continental sites in Germany. Tellus 47B:23-34.
- Schmidt, M., R. Graul, H. Sartorius, and I. Levin. 1996. Carbon dioxide and methane in continental Europe: a climatology, and 222Radon-based emission estimates. Tellus 48B:457-473.
CITE AS: Uhse, K., M. Schmidt and I. Levin. 1998. Atmospheric CO2 records from sites in the UBA air sampling network. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A.
8/11/1998 Prepared by Mónica Martínez and Tom Boden