Stable Carbon Isotope (13C) in CH4 and CO, and Deuterium in CH4, in Atmospheric Samples from Niwot Ridge, Colorado, and Montana de Oro, California, United States (DB-1002)

This database contains atmospheric methane and carbon monoxide concentrations, and associated stable carbon isotope (d13C) and deuterium in CH4 measurements from air samples collected at approximately bi-weekly intervals from two fixed surface sites in the United States. These sites are: Niwot Ridge, CO, a mid-continental site (41°N, 105°W); and Montana de Oro, CA (35°N, 121°W), a Pacific Coast site receiving strong westerlies. Continuous records of CH4 and CO mixing ratios, and Delta 13C-CH4 extend back through 1995 at Niwot Ridge, and back through 1996 at Montana de Oro. Deuterium ratios in CH4 have been recorded since August 1998 at Niwot Ridge and June 2000 at Montana de Oro. Records of 3CO begin in January 2000 at Niwot Ridge and June 2000 at Montaña de Oro. Such time series can provide information about: (1) seasonal cycling of CH4 and CO sources and sinks in background air, (2) trends in atmospheric concentrations of CH4 and their stable carbon and hydrogen isotopes, and (3) the distribution of the hydroxyl (OH) radical in the atmosphere. The data presented here are discussed in Tyler et al. (1999).

For more information on methods, please visit the database description in Trends Online at [http://cdiac.ornl.gov/epubs/db/db1022/db1022.html].