Identification

Title

Patterns of CO₂ and radiocarbon across high northern latitudes during International Polar Year 2008

Abstract

High-resolution in situ CO₂ 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 CO₂ concentrations were investigated using coincident CO, black carbon, CH₃CN, HCN, O₃, C2Cl4, and Δ¹ ⁴CO₂ data, and the FLEXPART model. In spring, the CO₂ 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 CO₂ 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 CO₂ 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 CO₂ to CO emission ratios of 4 to 16 ppmv ppmv-1 and a mean CO₂ emission factor of 1698 ± 280 g kg-1 dry matter. From the ¹ ⁴C in CO₂ content of 48 whole air samples, mean spring (46.6 ± 4.4‰) and summer (51.5 ± 5‰) Δ¹ ⁴CO₂ 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 Δ¹ ⁴CO₂ values were observed in <1% of the data set. Rather, ARCTAS Δ¹ ⁴CO₂ 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 Δ¹ ⁴CO₂ 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 Δ¹ ⁴CO₂ observations in a warming Arctic, representing an additional source of uncertainty in the quantification of fossil fuel CO₂.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7mw2hn5

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

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South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2011-07-16T00:00:00Z

Frequency of update

Quality and validity

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Conformity

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name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact