In:
Radiocarbon, Cambridge University Press (CUP), Vol. 55, No. 3 ( 2013), p. 1484-1495
Abstract:
The radiocarbon content of whole air provides a theoretically ideal and now observationally proven tracer for recently added fossil-fuel-derived CO 2 in the atmosphere ( C ff ). Over large industrialized land areas, determination of C ff also constrains the change in CO 2 due to uptake and release by the terrestrial biosphere. Here, we review the development of a Δ 14 CO 2 measurement program and its implementation within the US portion of the NOAA Global Monitoring Division's air sampling network. The Δ 14 CO 2 measurement repeatability is evaluated based on surveillance cylinders of whole air and equates to a C ff detection limit of 〈 0.9 ppm from measurement uncertainties alone. We also attempt to quantify additional sources of uncertainty arising from non-fossil terms in the atmospheric 14 CO 2 budget and from uncertainties in the composition of “background” air against which C ff enhancements occur. As an example of how we apply the measurements, we present estimates of the boundary layer enhancements of C ff and C bio using observations obtained from vertical airborne sampling profiles off of the northeastern US. We also present an updated time series of measurements from NOAA GMD's Niwot Ridge site at 3475 m asl in Colorado in order to characterize recent Δ 14 CO 2 variability in the well-mixed free troposphere.
Type of Medium:
Online Resource
ISSN:
0033-8222
,
1945-5755
DOI:
10.1017/S0033822200048414
Language:
English
Publisher:
Cambridge University Press (CUP)
Publication Date:
2013
detail.hit.zdb_id:
2028560-7
SSG:
11
SSG:
13
Permalink
