A new high precision14CO2time series for North American continental air
| Autor: | John Southon, John B. Miller, Rodger Sparks, Pieter P. Tans, Jocelyn Turnbull, Scott J. Lehman |
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| Rok vydání: | 2007 |
| Předmět: |
Atmospheric Science
Meteorology Soil Science Aquatic Science Oceanography Atmospheric sciences law.invention Carbon cycle Troposphere chemistry.chemical_compound New england Geochemistry and Petrology law Synoptic scale meteorology Earth and Planetary Sciences (miscellaneous) Radiocarbon dating Earth-Surface Processes Water Science and Technology Ecology Paleontology Forestry Isotopic composition Geophysics chemistry Space and Planetary Science Greenhouse gas Carbon dioxide Environmental science |
| Zdroj: | Journal of Geophysical Research. 112 |
| ISSN: | 0148-0227 |
| Popis: | We develop a high precision Δ 14 CO 2 measurement capability in 2-5 L samples of whole air for implementation within existing greenhouse gas flask sampling networks. The long-term repeatability of the measurement is 1.8%o (1-sigma), as determined from repeated analyses of quality control standards and replicate extraction and measurement of authentic field samples. In a parallel effort, we have begun a Δ 14 CO 2 measurement series from NOAA/ESRL's (formerly NOAA/CMDL) surface flask sampling site at Niwot Ridge, Colorado, USA (40.05°N, 105.58°W, 3475 masl) in order to monitor the isotopic composition of carbon dioxide in relatively clean air over the North American continent. Δ 14 CO 2 at Niwot Ridge decreased by 5.7‰/yr from 2004 to 2006, with a seasonal amplitude of 3-5%o. A comparison with measurements from the free troposphere above New England, USA (41°N, 72°W) indicates that the Δ 14 CO 2 series at the two sites are statistically similar at timescales longer than a few days to weeks (i.e., those of synoptic scale variations in transport), suggesting that the Niwot Ridge measurements can be used as a proxy for North American free tropospheric air in future carbon cycle studies. |
| Databáze: | OpenAIRE |
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