scholarly journals Modeling of Atmospheric Radiocarbon Fluctuations for the Past Three Centuries

Radiocarbon ◽  
1983 ◽  
Vol 25 (2) ◽  
pp. 249-258 ◽  
Author(s):  
P E Damon ◽  
R S Sternberg ◽  
C J Radnell
Keyword(s):  
Magnetic Field ◽  
Fossil Fuels ◽  
Magnetic Field Intensity ◽  
Cosmic Ray ◽  
Solar Modulation ◽  
Geomagnetic Index ◽  
The Past ◽  
Dipole Magnetic Field ◽  
Climatic Time Series ◽  
Sunspot Record

Relatively precise quantitative observations of geophysical parameters are available to evaluate the fluctuations of atmospheric 14C activity during the past three centuries. As reviewed by Damon, Lerman, and Long (1978), these fluctuations seem to result from three factors: 1) changes in the earth's dipole magnetic field intensity, which has been decreasing since the first measurements by Gauss (McDonald and Gunst, 1968); 2) solar modulation of the cosmic-ray production, which has been correlated with the sunspot record of Waldmeier (1961), and more recently, to the Aa geomagnetic index by Stuiver and Quay (1980); and 3) the combustion of fossil fuels (Suess, 1955). A relationship between the climatic time series and the 14C-derived record of solar change has not yet been demonstrated (Stuiver, 1980).

The Accuracy of Radiocarbon Dates

Antiquity ◽  
1963 ◽  
Vol 37 (147) ◽  
pp. 213-219 ◽  
Author(s):  
W. F. Libby
Keyword(s):  
Magnetic Field ◽  
Solar System ◽  
Cosmic Ray ◽  
Average Life ◽  
Radiocarbon Dates ◽  
Cosmic Ray Intensity ◽  
Rapid Mixing ◽  
The Past ◽  
The Earth ◽  
The Magnetic Field

The first test of the accuracy of dates obtained by the radiocarbon technique was made by determining whether dates so obtained agreed with the historical dates for materials of known age (n. 1). The validity of the radiocarbon method continues to be an important question, especially in the light of the numerous results that have been accumulated and the greater precision of the technique during the past few years (n. 2).The radiocarbon content of the biosphere depends on three supposedly independent geophysical quantities: (i) the average cosmic ray intensity over a period of 8000 years (the average life of radiocarbon) as measured in our solar system but outside the earth's magnetic field (n. 1); (ii) the magnitude (but not the orientation, because of the relatively rapid mixing over the earth's surface) of the magnetic field in the vicinity of the earth, averaged over the same period (n. 1,3); and (iii) the degree of mixing of the oceans during the same period (n. 1). The question of the accuracy of radiocarbon dates therefore is of interest to geophysicists in general as well as to the archaeologists, geologists and historians who use the dates.Previous workers in this area (n. 1, 2) have reported some discrepancies, and it is the purpose here to consider the matter further.

Fluctuations of atmospheric carbon-14 concentrations during the past century

1971 ◽  
Vol 321 (1544) ◽  
pp. 105-127 ◽  
Keyword(s):  
Solar Activity ◽  
Production Rate ◽  
Cosmic Ray ◽  
Solar Modulation ◽  
Past Century ◽  
Activity Maximum ◽  
Carbon 14 ◽  
The Past ◽  
Natural Carbon ◽  
Atmospheric Carbon

Variations in atmospheric carbon-14 concentrations during the past century have been studied through the analyses of wines, spirits and plant seeds. The results reveal that short-term fluctuations of carbon-14 concentrations have occurred which are negatively correlated with solar activity. Maximum correlation occurs with carbon-14 concentration minima preceding sunspot maxima by one year. The overall magnitude of the fluctuations, 3 % of the natural carbon-14 concentration, appears too large to be attributed to variations in the isotope production rate by solar modulation of the galactic cosmic ray flux. It is proposed that the fluctuations are the result of solar-sensitive mixing of stratospheric and tropospheric air masses through variations of the incident ultraviolet and corpuscular radiation over each solar cycle. Theoretical considerations require that stratospheric carbon-14 levels fluctuate in direct correlation with solar activity. These variations of natural carbon-14 activities in the troposphere represent a significant deviation from the basic assumption of the radiocarbon dating method and may introduce further uncertainty in the dating of ‘young’ materials. In addition, they endorse the universal use of the N. B. S. modern standard in carbon -14 assay. A long-term decrease in tropospheric carbon-14 concentrations was also observed and is attributed to a reduction in the mean production rate of carbon-14 through enhanced solar activity.

scholarly journals Patterns of Atmospheric 14C Changes

Radiocarbon ◽  
1980 ◽  
Vol 22 (2) ◽  
pp. 166-176 ◽  
Author(s):  
Minze Stuiver ◽  
Paul D Quay
Keyword(s):  
Solar Wind ◽  
Geomagnetic Field ◽  
Cosmic Ray ◽  
Solar Modulation ◽  
Production Rates ◽  
Climatic Fluctuation ◽  
The Past ◽  
Earth Magnetic Field ◽  
Carbon Reservoir ◽  
Cosmic Ray Flux

Natural atmospheric 14C changes are caused by fluctuations in upper atmospheric 14C production rates (Q) that are related to earth geomagnetic field variations and changes in solar wind magnetic shielding properties. Climate variability may also be responsible for some of the changes because it influences exchange rates of 14C between the various terrestrial carbon reservoirs.Upper atmospheric 14C production rates QM, in at/sec cm2 (earth), were calculated for the past 1200 years from the atmospheric 14C record and a carbon reservoir model. The changes in QM are compared in detail with the predicted Q variability derived from an Aa solar modulation mechanism and 20th century neutron flux observations. The influence of earth geomagnetic field changes on the magnitude of the solar wind modulation is discussed, and it is shown that the variations in this magnitude agree with the known differences in earth magnetic field intensity during the past 1200 years. The larger calculated QM oscillations during the sixth millennium bp also agree with this concept.Solar wind magnetic as well as geomagnetic forces modulate the incoming cosmic ray flux and explain the main features of the atmospheric 14C record. It is argued that climatic fluctuation is not a dominant cause.The oscillations between 3200 and 3700 BC, as measured by de Jong, Mook, and Becker, differ in rise time from those found for the current millennium.

Evidence for changes in the Earth’s magnetic field intensity

1970 ◽  
Vol 269 (1193) ◽  
pp. 47-55 ◽  
Keyword(s):  
Magnetic Field ◽  
Field Intensity ◽  
Remanent Magnetization ◽  
Magnetic Field Intensity ◽  
Earth’S Magnetic Field ◽  
The Past ◽  
Earth's Magnetic Field ◽  
Historical Past ◽  
Archaeological Objects ◽  
Periodical Change

Archaeomagnetic investigations based on the measurement of remanent magnetization in baked archaeological objects and rocks show considerable changes in the Earth’s magnetic field in the historical past. The curve characterizing the Earth’s intensity during the past 8500 years has its maximum around 400 to 100 b. c. when the field reaches 1.6 times its present intensity and its minimum around 4000 b. c.when the field drops to around 0.6 times its present intensity. On the smoothed curves with a periodical change of approximately 8900 years, changes with shorter periods are superimposed which can also be observed in declination and inclination. Results of archaeomagnetic investigations of samples from different areas on the Earth’s surface are discussed with the aim of defining the whole world and non­-dipole changes in the field moment. Possible connexions between the Earth’s magnetic field and 14 C decay are discussed on the basis of magnetic results, and the approximate character of changes in the Earth’s field during the past 20000 years is given.

scholarly journals Heliospheric Modulation of GCR at Mid and High Latitudes

2020 ◽  
pp. 44-55
Author(s):  
Kingsley Chukwudi Okpala ◽  
Darlene Florence Kalu ◽  
Nnaemeka Onyekachi Njoku- Achu
Keyword(s):  
Magnetic Field ◽  
Time Lag ◽  
Cosmic Ray ◽  
Geomagnetic Index ◽  
Total Magnetic Field ◽  
Wave Characteristics ◽  
The Mean ◽  
Cycle 24 ◽  
Galactic Cosmic Ray ◽  
Activity Indices

The variations of Galactic Cosmic Ray (GCR) as compared with the behaviour of various solar activity indices, heliospheric parameters and the geomagnetic index Ap during 1999-2015, which covers part of cycles 23 and cycle 24 have been studied.  Two sets of data were considered, consisting respectively of all days of the month and the five quietest days. Neutron Monitor Stations of Moscow and Rome (mid latitude stations) and Inuvik and Oulu (High latitude stations) were employed. Cosmic Ray (CR) wave characteristics were obtained by the harmonics method.  The mean, diurnal amplitude of the first, second, and third harmonics were calculated and profiled. Furthermore, correlation analysis was carried out to determine the association between parameters. Results showed that the total magnetic field BT and the sunspot number (SSN) showed the strongest association with CR in both quiet conditions and all day conditions considered. The higher harmonics showed a slightly stronger association with CR than lower harmonics. A time-lag of about 12-15 months was observed for SSN suggesting a potential for predicting CR flux, while the total magnetic field had a zero lag for all the heliospheric parameters considered.

Cosmic ray modulations related to the interplanetary magnetic field intensity

1983 ◽  
Vol 88 (A4) ◽  
pp. 2973 ◽  
Author(s):  
S. P. Duggal ◽  
M. A. Pomerantz ◽  
R. K. Schaefer ◽  
C. H. Tsao
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Cosmic Ray

BP Global Energy Outlook 2030

2013 ◽  
pp. 109-128 ◽  
Author(s):  
C. Rühl
Keyword(s):  
Emerging Economies ◽  
Energy Demand ◽  
Fossil Fuels ◽  
Net Energy ◽  
Global Energy ◽  
The Past ◽  
Market Shares ◽  
The Us ◽  
Almost All ◽  
Oil Gas

This paper presents the highlights of the third annual edition of the BP Energy Outlook, which sets out BP’s view of the most likely developments in global energy markets to 2030, based on up-to-date analysis and taking into account developments of the past year. The Outlook’s overall expectation for growth in global energy demand is to be 36% higher in 2030 than in 2011 and almost all the growth coming from emerging economies. It also reflects shifting expectations of the pattern of supply, with unconventional sources — shale gas and tight oil together with heavy oil and biofuels — playing an increasingly important role and, in particular, transforming the energy balance of the US. While the fuel mix is evolving, fossil fuels will continue to be dominant. Oil, gas and coal are expected to converge on market shares of around 26—28% each by 2030, and non-fossil fuels — nuclear, hydro and renewables — on a share of around 6—7% each. By 2030, increasing production and moderating demand will result in the US being 99% self-sufficient in net energy. Meanwhile, with continuing steep economic growth, major emerging economies such as China and India will become increasingly reliant on energy imports. These shifts will have major impacts on trade balances.

Open Localization in Micro LeadFrame Package Using Space Domain Reflectometry

2013 ◽  
Author(s):  
J. Gaudestad ◽  
V. Talanov ◽  
A. Orozco ◽  
M. Marchetti
Keyword(s):  
Magnetic Field ◽  
Radio Frequency ◽  
Standing Wave ◽  
High Resistance ◽  
Space Domain ◽  
The Past ◽  
Open Defects ◽  
Rf Electronics ◽  
Rf Signal ◽  
The Magnetic Field

Abstract In the past couple years, Space Domain Reflectometry (SDR) has become a mainstream method to locate open defects among the major semiconductor manufacturers. SDR injects a radio frequency (RF) signal into the open trace creating a standing wave with a node at the open location. The magnetic field generated by the standing wave is imaged with a SQUID sensor using RF electronics. In this paper, we show that SDR can be used to non-destructively locate high resistance failures in Micro LeadFrame Packages (MLP).

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