Vay, S. A. and Choi, Y. and Vadrevu, K. P. and Blake, D. R. and Tyler, S. C. and Wisthaler, A. and Hecobian, A. and Kondo, K. and Diskin, G. S. and Sachse, G. W. and Woo, J.-H. and Weinheimer, A. J. and Burkhart, J. F. and Stohl, A. and Wennberg, P. O. (2011) Patterns of CO_2 and radiocarbon across high northern latitudes during International Polar Year 2008. Journal of Geophysical Research D, 116 . Art. No. D14301. ISSN 0148-0227 http://resolver.caltech.edu/CaltechAUTHORS:20110804-090820448
- Published Version
See Usage Policy.
Use this Persistent URL to link to this item: http://resolver.caltech.edu/CaltechAUTHORS:20110804-090820448
High-resolution in situ CO_2 measurements were conducted aboard the NASA DC-8 aircraft during the ARCTAS/POLARCAT field campaign, a component of the wider 2007–2008 International Polar Year activities. Data were recorded during large-scale surveys spanning the North American sub‐Arctic to the North Pole from 0.04 to 12 km altitude in spring and summer of 2008. Influences on the observed CO_2 concentrations were investigated using coincident CO, black carbon, CH_3CN, HCN, O_3, C_2Cl_4, and Δ^(14)CO_2 data, and the FLEXPART model. In spring, the CO_2 spatial distribution from 55°N to 90°N was largely determined by the long-range transport of air masses laden with Asian anthropogenic pollution intermingled with Eurasian fire emissions evidenced by the greater variability in the mid-to-upper troposphere. At the receptor site, the enhancement ratios of CO_2 to CO in pollution plumes ranged from 27 to 80 ppmv ppmv^(−1) with the highest anthropogenic content registered in plumes sampled poleward of 80°N. In summer, the CO_2 signal largely reflected emissions from lightning-ignited wildfires within the boreal forests of northern Saskatchewan juxtaposed with uptake by the terrestrial biosphere. Measurements within fresh fire plumes yielded CO_2 to CO emission ratios of 4 to 16 ppmv ppmv^(−1) and a mean CO_2 emission factor of 1698 ± 280 g kg^(−1) dry matter. From the ^(14)C in CO_2 content of 48 whole air samples, mean spring (46.6 ± 4.4‰) and summer (51.5 ± 5‰) Δ^(14)CO_2 values indicate a 5‰ seasonal difference. Although the northern midlatitudes were identified as the emissions source regions for the majority of the spring samples, depleted Δ^(14)CO_2 values were observed in <1% of the data set. Rather, ARCTAS Δ^(14)CO_2 observations (54%) revealed predominately a pattern of positive disequilibrium (1–7‰) with respect to background regardless of season owing to both heterotrophic respiration and fire-induced combustion of biomass. Anomalously enriched Δ^(14)CO_2 values (101–262‰) measured in emissions from Lake Athabasca and Eurasian fires speak to biomass burning as an increasingly important contributor to the mass excess in Δ^(14)CO_2 observations in a warming Arctic, representing an additional source of uncertainty in the quantification of fossil fuel CO_2.
|Additional Information:||© 2011 American Geophysical Union. Received 15 January 2011; revised 27 March 2011; accepted 25 April 2011; published 16 July 2011. The authors wish to thank Xiaomei Xu, Scott Lehman, and Ingeborg Levin for use of the Point Barrow, Niwot Ridge, and Jungfraujoch Δ^(14)CO_2 data, respectively. We also appreciate the CO_2 data provided by Doug Worthy of Environment Canada and NOAA ESRL, as well as contributions from Melissa Yang. We are most grateful to Jimmy Geiger, Jim Plant, and the DC-8 crew whose valuable contributions ensured a successful and safe mission. This research was funded by NASA’s Global Tropospheric Chemistry and Radiation Sciences Programs. CH_3CN measurements were supported by the Austrian Research Promotion Agency (FFG-ALR) and the Tiroler Zukunftstiftung, and carried out with the help/support of T. Mikoviny, M. Graus, A. Hansel, and T. D. Maerk.|
|Subject Keywords:||^(14)CO_2, ARCTAS, CO_2, International Polar Year, POLARCAT, airborne observations|
|Official Citation:||Vay, S. A., et al. (2011), Patterns of CO2 and radiocarbon across high northern latitudes during International Polar Year 2008, J. Geophys. Res., 116, D14301, doi:10.1029/2011JD015643|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Benjamin Perez|
|Deposited On:||04 Aug 2011 17:21|
|Last Modified:||26 Dec 2012 13:27|
Repository Staff Only: item control page