This paper presents a compilation of atmospheric radiocarbon for the period 1950–2019, derived from atmospheric CO2 sampling and tree rings from clean-air sites. Following the approach taken by Hua ...et al. (2013), our revised and extended compilation consists of zonal, hemispheric and global radiocarbon (14C) data sets, with monthly data sets for 5 zones (Northern Hemisphere zones 1, 2, and 3, and Southern Hemisphere zones 3 and 1–2). Our new compilation includes smooth curves for zonal data sets that are more suitable for dating applications than the previous approach based on simple averaging. Our new radiocarbon dataset is intended to help facilitate the use of atmospheric bomb 14C in carbon cycle studies and to accommodate increasing demand for accurate dating of recent (post-1950) terrestrial samples.
The chronology of Machu Picchu was traditionally associated with the period attributed to the reign of Pachacuti Inca Yupanqui. Within the scheme of the so-called “historical chronology”, proposed by ...John H. Rowe in 1945, the ascension to power of Pachacuti Inca took place around 1438 CE, and the construction of Machu Picchu began by 1450–1460 CE. Several radiocarbon-dated samples may help to understand the chronology of the construction of llaqta of Machu Picchu, Chachabamba, and Choqesuysuy. However, there is a lack of consensus between different radiocarbon-based Inca chronologies because of the lack of information of which calibration curves to use: Northern Hemisphere (NH), Southern Hemisphere (SH), or a mixed calibration curve? Thus, the main goal of the present investigation is to develop a new methodological approach to reconstruct a radiocarbon-based Incan chronology, an approach based on the determination, through modeling, of the proportion of NH and SH air parcels arriving at three relevant Inca settlements. We found air parcel contributions from the NH and SH for Machu Picchu (51% NH and 49% SH), Chamical (29% NH and 71% SH), and Tiquischullpa (41% NH and 59% SH). Thereby, our investigation brings three proportions to mix NH and SH 14C curves, based on an empirical method and supported by a high-resolution paleoclimatic tracer, for Inca radiocarbon dating studies. Our study emphasizes that great attention should be paid when applying radiocarbon calibration to radiocarbon measurements of samples originating from regions under the influence of the atmospheric circulation-boundary between hemispheres.
In this paper, a record of the 14C and 13C isotope content of atmospheric CO2 for Gliwice is presented for samples collected on a weekly basis in the years 2011–2013. In addition, measurements were ...performed on the early and late wood from the annual rings of pine trees from five sites located 3–6 km from the atmospheric CO2 sampling point. The concentration of 14C in CO2 samples from the air was much lower relative to the concentration of this isotope in “clean air,” indicating a pronounce Suess effect, with a mean Δ14C lower by ca. 60‰ than Jungfraujoch data when the 15% of the highest differences are excluded, which leads to the FFCO2 estimate of 5.8%. In winter, the main source of fossil CO2 was fuel combustion, as confirmed by significant correlations with air pollutants. In the vegetation seasons, the Δ14C was highly variable due to biogenic influence and more variable winds. The isotopic results were also affected by an additional significant CO2 source for the Gliwice air, which was a closed mine shaft. The Δ14C and δ13C in tree rings did not record a strong Suess effect in the years 2008–2013 in woodland areas around Gliwice city.
An increase in atmospheric radiocarbon (14C) content of about 11.3‰ in the period AD 993–994 was observed in annual tree rings from Japanese cedar (Cryptomeria japonica) and Hinoki cypress ...(Chamaecyparis obtusa) (Miyake et al. 2013, 2014). Single-year samples of dendrochronologically dated tree rings (English oak, Quercus robur) from Kujawy, a village near Krakow (SE Poland), spanning the years AD 981–1000, were collected, and their 14C content was measured using the AMS system in the Leibniz Laboratory. The results clearly show an increase of 6.2±1.6‰ in the 14C concentration in tree rings between AD 993 and 994, with a maximum increase of 10.9±1.7‰ between AD 991 and 994.
Evidence of a rapid increase in atmospheric radiocarbon (14C) content in AD 774–775 was presented by Miyake et al. (2012), who observed an increase of about 12‰ in the 14C content in annual tree ...rings from Japanese cedar. Usoskin et al. (2013) report a similar 14C spike in German oak, and attribute it to exceptional solar activity. If this phenomenon is global in character, such rapid changes in 14C concentration may affect the accuracy of calibrated dates, as the existing calibration curve is composed mainly of decadal samples. Single-year samples of dendro-chronologically dated tree rings of deciduous oak (Quercus robur) from Kujawy, a village near Krakow (SE Poland), spanning the years AD 765–796, were collected and their 14C content was measured using the AMS system in the Leibniz Laboratory. The results clearly show a rapid increase of 9.2±2.1‰ in the 14C concentration in tree rings between AD 774 and AD 775, with maximum Δ14C=4.1±2.3‰ noted in AD 776.
Radiocarbon method in environmental monitoring of CO2 emission Rakowski, Andrzej Z.; Nadeau, Marie-Josee; Nakamura, Toshio ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
January 2013, 2013-01-00, 20130101, Letnik:
294
Journal Article
Recenzirano
New results of carbon isotopic composition from tree rings have been analyzed. Δ14C and δ13C data, representing the isotopic composition of carbon in “clean air”, were obtained from annual rings of a ...pine tree (Pinus sylvestris) taken in the Niepołomice area, 25km east Kraków, Poland. All samples were processed to extract α-cellulose, and the radiocarbon concentration in each annual ring was measured using AMS at the University of Nagoya. Stable isotopic composition of carbon was determined using isotope ratio mass spectrometry. The dataset covers the growth period between 1960 and 2003. The average difference between radiocarbon concentrations in Niepołomice and the North Hemisphere zone 1 (NH zone 1) for the period between 1960 and 1999 is 3.5±1.6‰. These data are compared with previously presented results from the city of Kraków, where a local decrease in 14C concentration was observed due to local CO2 emission from fossil fuel use. The differences in observed 14C concentrations were used to estimate a magnitude of the local Suess effect in Kraków. Based on mass balance equations for CO214C concentrations, it was possible to calculate the CO2 concentration associated with fossil fuel emission (Cfoss) into the atmosphere. The highest values of Cfoss were recorded in the years 1986 (11.9±1.4ppmV) and 1983 (8.1±1.3ppmV), while the lowest value of 0.6±1.8ppmV was recorded in 2001.
Radiocarbon concentration in the atmosphere is significantly lower in areas where man-made emissions of carbon dioxide occur. This phenomenon is known as Suess effect, and is caused by the ...contamination of clean air with non-radioactive carbon from fossil fuel combustion. The effect is more strongly observed in industrial and densely populated urban areas. Measurements of carbon isotope concentrations in a study area can be compared to those from areas of clear air in order to estimate the amount of carbon dioxide emission from fossil fuel combustion by using a simple mathematical model. This can be calculated using the simple mathematical model. The result of the mathematical model followed in this study suggests that the use of annual rings of trees to obtain the secular variations of 14C concentration of atmospheric CO2 can be useful and efficient for environmental monitoring and modeling of the carbon distribution in local scale.
Radiocarbon concentration in modern tree rings from Valladolid, Spain Rakowski, Andrzej Z.; Nakamura, Toshio; Pazdur, Anna ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
04/2010, Letnik:
268, Številka:
7
Journal Article
Recenzirano
New results of radiocarbon concentration in tree rings from the City of Valladolid (Spain) covering a growth period of 22
year have been measured using an AMS. Samples were taken using a hollow drill ...from a living tree, and α-cellulose was extracted from each of annual rings (early and late wood separately). The set of data shows lower radiocarbon concentration than that reported for “clean air” at the reference station, indicating a remarkable input of “dead” CO
2 of fossil fuel origin. Using data of carbon dioxide and
14C concentrations from Schauinsland, the corresponding summer and winter values of the fossil component (
c
f) in carbon dioxide were calculated for the City of Valladolid. By fitting exponential and linear functions to the experimental data, the exchange time was calculated, and the expected future
14C concentration in the atmosphere was estimated.
PDF
