Radiocarbon in modern Carbon Cycle research

2020 ◽  
Author(s):  
Ingeborg Levin
Keyword(s):  
Carbon Cycle ◽  
Fossil Fuel ◽  
Environmental Sciences ◽  
Anthropogenic Input ◽  
Isotope Tracer ◽  
Continental Scale ◽  
Nuclear Weapon Testing ◽  
Bomb Radiocarbon ◽  
Weapon Testing ◽  
Transient Tracer

<p>Atmospheric nuclear weapon testing in the 1950s and 1960s has been worrying, however, in many aspects it was extremely beneficial for environmental sciences. The artificial production of more than 6 x 10<sup>28</sup> atoms or about 0.6 tons of <sup>14</sup>C, leading to a doubling of the <sup>14</sup>C/C ratio in tropospheric CO<sub>2</sub> of the Northern Hemisphere has generated a prominent <sup>14</sup>C spike in 1963. This “bomb-spike” has been used as transient tracer in all compartments of the carbon cycle, but also to study atmospheric dynamics, such as inter-hemispheric and stratosphere-troposphere air mass exchange. Moreover, our attempt to accurately determine total bomb produced <sup>14</sup>C led to improved estimates of the atmosphere-ocean gas exchange rate and to a new constraint of the residence time of carbon in the terrestrial biosphere. Today, the transient bomb-radiocarbon signal has levelled off, and the anthropogenic input of radiocarbon-free fossil fuel CO<sub>2</sub> into the atmosphere has become the dominant driver of the decreasing <sup>14</sup>C/C ratio in atmospheric CO<sub>2</sub>; the observed trend may thus help scrutinising the total global release of fossil fuel CO<sub>2</sub> into the atmosphere. Prominent examples where the bomb <sup>14</sup>C disturbance has been successfully used to study dynamic processes in the carbon cycle are discussed as well as our current activities applying this unique isotope tracer for continental scale carbon cycle budgeting.</p>

Radiocarbon in modern carbon cycle research

2021 ◽  
Author(s):  
Ingeborg Levin
Keyword(s):  
Carbon Cycle ◽  
Fossil Fuel ◽  
Regional Scale ◽  
Anthropogenic Input ◽  
Isotope Tracer ◽  
Continental Scale ◽  
Nuclear Weapon Testing ◽  
Bomb Radiocarbon ◽  
Weapon Testing ◽  
Transient Tracer

<p>Atmospheric nuclear weapon testing in the 1950s and 1960s has been worrying, however, in many aspects it was extremely beneficial for environmental sciences. The artificial production of more than 6 x 10<sup>28</sup> atoms or about 0.6 tons of radiocarbon (<sup>14</sup>C), leading to a doubling of the <sup>14</sup>C/C ratio in tropospheric CO<sub>2</sub> of the Northern Hemisphere, has generated a prominent spike in 1963. This “bomb-spike” has been used as transient tracer in all compartments of the carbon cycle, but also to study atmospheric dynamics, such as inter-hemispheric and stratosphere-troposphere air mass exchange. Moreover, our attempt to accurately determine total bomb produced <sup>14</sup>C led to improved estimates of the atmosphere-ocean gas exchange rate and to a new constraint of the residence time of carbon in the terrestrial biosphere. Today, the transient bomb-radiocarbon signal has levelled off, and the anthropogenic input of radiocarbon-free fossil fuel CO<sub>2</sub> into the atmosphere has become the dominant driver of the <sup>14</sup>C/C ratio in global atmospheric CO<sub>2</sub>. The observed decreasing <sup>14</sup>C/C trend in atmospheric CO<sub>2</sub> may thus help scrutinising the total global release of fossil fuel CO<sub>2</sub> into the atmosphere. On the local and regional scale, atmospheric <sup>14</sup>C/C measurements are already routinely conducted to separate fossil fuel from biogenic CO<sub>2</sub> signals and to estimate trends of regional fossil fuel CO<sub>2</sub> emissions. Some prominent examples where the bomb <sup>14</sup>CO<sub>2</sub> disturbance has been successfully used to study dynamic processes in the carbon cycle are discussed as well as our current activities applying this unique isotope tracer for continental scale carbon cycle budgeting.</p>

scholarly journals Cambridge University Natural Radiocarbon Measurements IV: Nuclear-Weapon Testing and the Atmospheric Radiocarbon Concentration

Radiocarbon ◽  
1961 ◽  
Vol 3 ◽  
pp. 77-80 ◽  
Author(s):  
H. Godwin ◽  
E. H. Willis
Keyword(s):  
Rapid Growth ◽  
Nuclear Weapon ◽  
Annual Ring ◽  
Populus Nigra ◽  
Annual Rings ◽  
Cambridge University ◽  
Annual Crops ◽  
Nuclear Weapon Testing ◽  
Weapon Testing

In continuance of investigations upon successive annual crops of oats reported in Radiocarbon Supplement, Volume 2, we undertook the analysis of successive annual rings of a tree that had been growing throughout the period covered by the oat-crop assays, namely 1953 to 1959. The selected tree was a straight-boled specimen of Populus nigra from the Forestry Commission's plantations at Santon Downham, near Thetford, Norfolk. It had been planted in 1929 and was felled on 21 October, 1959. Shortly afterwards, it was brought into the laboratory and sawn into slices just over 1 in. thick. The surfaces having been smoothed, the annual-ring contacts were marked, and within each annual ring the inner (spring) wood was marked off from the outer (autumn) wood. The tree had been chosen as one exhibiting rapid growth and it proved fairly easy to dissect off with a chisel all the separate half-rings between spring 1953 and the end of 1959. In the event, activities were determined only upon four of the half or whole rings.

scholarly journals Multicentury Changes to the Global Climate and Carbon Cycle: Results from a Coupled Climate and Carbon Cycle Model

2005 ◽  
Vol 18 (21) ◽  
pp. 4531-4544 ◽  
Author(s):  
G. Bala ◽  
K. Caldeira ◽  
A. Mirin ◽  
M. Wickett ◽  
C. Delire
Keyword(s):  
Carbon Cycle ◽  
Radiative Forcing ◽  
Fossil Fuel ◽  
Global Climate ◽  
Second Century ◽  
Cycle Model ◽  
Carbon Cycle Model ◽  
Living Biomass ◽  
Long Term Consequences

Abstract A coupled climate and carbon (CO2) cycle model is used to investigate the global climate and carbon cycle changes out to the year 2300 that would occur if CO2 emissions from all the currently estimated fossil fuel resources were released to the atmosphere. By the year 2300, the global climate warms by about 8 K and atmospheric CO2 reaches 1423 ppmv. The warming is higher than anticipated because the sensitivity to radiative forcing increases as the simulation progresses. In this simulation, the rate of emissions peaks at over 30 Pg C yr−1 early in the twenty-second century. Even at the year 2300, nearly 50% of cumulative emissions remain in the atmosphere. Both soils and living biomass are net carbon sinks throughout the simulation. Despite having relatively low climate sensitivity and strong carbon uptake by the land biosphere, these model projections suggest severe long-term consequences for global climate if all the fossil fuel carbon is ultimately released into the atmosphere.

scholarly journals Current systematic carbon-cycle observations and the need for implementing a policy-relevant carbon observing system

2014 ◽  
Vol 11 (13) ◽  
pp. 3547-3602 ◽  
Author(s):  
P. Ciais ◽  
A. J. Dolman ◽  
A. Bombelli ◽  
R. Duren ◽  
A. Peregon ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Carbon Cycle ◽  
Fossil Fuel ◽  
The Arctic ◽  
Observation System ◽  
Observation Data ◽  
Current State ◽  
Spatial Coverage

Abstract. A globally integrated carbon observation and analysis system is needed to improve the fundamental understanding of the global carbon cycle, to improve our ability to project future changes, and to verify the effectiveness of policies aiming to reduce greenhouse gas emissions and increase carbon sequestration. Building an integrated carbon observation system requires transformational advances from the existing sparse, exploratory framework towards a dense, robust, and sustained system in all components: anthropogenic emissions, the atmosphere, the ocean, and the terrestrial biosphere. The paper is addressed to scientists, policymakers, and funding agencies who need to have a global picture of the current state of the (diverse) carbon observations. We identify the current state of carbon observations, and the needs and notional requirements for a global integrated carbon observation system that can be built in the next decade. A key conclusion is the substantial expansion of the ground-based observation networks required to reach the high spatial resolution for CO2 and CH4 fluxes, and for carbon stocks for addressing policy-relevant objectives, and attributing flux changes to underlying processes in each region. In order to establish flux and stock diagnostics over areas such as the southern oceans, tropical forests, and the Arctic, in situ observations will have to be complemented with remote-sensing measurements. Remote sensing offers the advantage of dense spatial coverage and frequent revisit. A key challenge is to bring remote-sensing measurements to a level of long-term consistency and accuracy so that they can be efficiently combined in models to reduce uncertainties, in synergy with ground-based data. Bringing tight observational constraints on fossil fuel and land use change emissions will be the biggest challenge for deployment of a policy-relevant integrated carbon observation system. This will require in situ and remotely sensed data at much higher resolution and density than currently achieved for natural fluxes, although over a small land area (cities, industrial sites, power plants), as well as the inclusion of fossil fuel CO2 proxy measurements such as radiocarbon in CO2 and carbon-fuel combustion tracers. Additionally, a policy-relevant carbon monitoring system should also provide mechanisms for reconciling regional top-down (atmosphere-based) and bottom-up (surface-based) flux estimates across the range of spatial and temporal scales relevant to mitigation policies. In addition, uncertainties for each observation data-stream should be assessed. The success of the system will rely on long-term commitments to monitoring, on improved international collaboration to fill gaps in the current observations, on sustained efforts to improve access to the different data streams and make databases interoperable, and on the calibration of each component of the system to agreed-upon international scales.

scholarly journals Determination of the Initial 137Cs Fallout on the Areas Contaminated by Chernobyl Fallout

2007 ◽  
Vol 26 (-1) ◽  
pp. 35-38 ◽  
Author(s):  
Grzegorz Poręba ◽  
Andrzej Bluszcz
Keyword(s):  
Precipitation Data ◽  
Chernobyl Fallout ◽  
Loess Area ◽  
Average Value ◽  
Soil Redistribution ◽  
South West ◽  
Nuclear Weapon Testing ◽  
Weapon Testing ◽  
137Cs Fallout

Determination of the Initial137Cs Fallout on the Areas Contaminated by Chernobyl FalloutThe fallout radioisotope137Cs is widely used to study rates and patterns of soil redistribution. This method requires the knowledge about the initial fallout of cesium in the study area. This paper describes the method of establishing the initial fallout of cesium for a study area which is contaminated by Chernobyl fallout. The study was carried out on the loess area near the Ujazd village (South-West Poland). The137Cs activities for reference soil cores varied from 4.41(24) kBq/m2to 5.97(26) kBq/m2. The average value of the reference inventory of137Cs for the study area is 5.23(15) kBq/m2. The calculated contribution of the Chernobyl137Cs fallout in the total cesium is equal 69%. Moreover the annual values of the137Cs fallout based on the precipitation data were calculated and presented. This study provides the method of calculating the137Cs fallout connected with the nuclear weapon testing based on the precipitation data. Moreover, this study also indicated that the spatial variability on the highly contaminated by Chernobyl cesium study area is small (RSD about 10%) and thus it is possible to use the cesium method to study soil redistribution.

Parameterization of a diagnostic carbon cycle model for continental scale application

2011 ◽  
Vol 115 (7) ◽  
pp. 1653-1664 ◽  
Author(s):  
David A. King ◽  
David P. Turner ◽  
William D. Ritts
Keyword(s):  
Carbon Cycle ◽  
Cycle Model ◽  
Carbon Cycle Model ◽  
Continental Scale
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