Atmospheric Carbon Dioxide Record from Westerland, 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.
Only technically biased values resulting from calibration problems or equipment malfunctions are removed. Daily mean values are calculated on the basis of half-hourly mean values related to local wind speed higher than 7.5 m/sec. Carrier gas corrections have been determined experimentally and applied on the basis of five CO2-in-air standards calibrated by Scripps Institution of Oceanography in 1988. The relative precision of the half-hourly readings is ~1 part per million by volume (ppmv). More details about the sampling methods, data selection criteria, and corrections are provided in Grosch et al. (1981), Levin (1991), and Levin et al. (1995).
Coastal station on Island of Sylt (North Sea)
54°56' N, 8°19' E
Atmospheric CO2 concentrations at Westerland rose from ~329 parts per million by volume (ppmv) in 1973 to ~364 ppmv in 1997. The atmospheric CO2 record from Westerland shows a seasonal pattern similar to other UBA sites; minimum values are recorded during July-September; maximum mixing ratios during November-March.
- Grosch, 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