scholarly journals Measurements of atmospheric He/N<sub>2</sub> as an indicator of fossil fuel extraction and stratospheric circulation

2020 ◽  
Author(s):  
Benjamin Birner ◽  
William Paplawsky ◽  
Jeffrey Severinghaus ◽  
Ralph F. Keeling
Keyword(s):  
Fossil Fuels ◽  
Fossil Fuel ◽  
Noble Gas ◽  
Inlet System ◽  
Mass Spectrometers ◽  
Human Fossil ◽  
Direct Measurements ◽  
Noble Gas Isotopes ◽  
Stratospheric Circulation ◽  
Gas Isotopes

Abstract. The atmospheric He/N2 ratio is expected to be increasing due to the emission of He associated with fossil fuels and is expected to also vary in both space and time due to gravitational separation in the stratosphere. These signals may be useful indicators of fossil-fuel exploitation and variability in stratospheric circulation, but direct measurements of He/N2 ratio are lacking on all time scales. Here we present a high-precision custom inlet system for mass spectrometers that continuously stabilizes the flow of gas during sample-standard comparison and removes all non-noble gases from the gas stream, enabling unprecedented accuracy in measurement of relative changes in the 4He/N2 ratio. Repeat measurements of the same combination of high-pressure tanks using our inlet system achieves a reproducibility of ~ 10 per meg (i.e. 0.001 %) in 6–8 h analyses. This compares to interannual changes of He/N2 gravitational enrichment at ~ 35 km in the mid latitude stratosphere of order 300–400 per meg, and an annual tropospheric increase from human fossil fuel activity of less than ~ 30 per meg y−1 (bounded by previous work on helium isotopes). The gettering and flow-stabilizing inlet may also be used for the analysis of other noble gas isotopes and could resolve previously unobserved seasonal cycles in Kr/N2 and Xe/N2.

scholarly journals A method for resolving changes in atmospheric He ∕ N<sub>2</sub> as an indicator of fossil fuel extraction and stratospheric circulation

2021 ◽  
Vol 14 (3) ◽  
pp. 2515-2527
Author(s):  
Benjamin Birner ◽  
William Paplawsky ◽  
Jeffrey Severinghaus ◽  
Ralph F. Keeling
Keyword(s):  
Fossil Fuels ◽  
Fossil Fuel ◽  
Noble Gas ◽  
Inlet System ◽  
Mass Spectrometers ◽  
Human Fossil ◽  
Direct Measurements ◽  
Noble Gas Isotopes ◽  
Stratospheric Circulation ◽  
Gas Isotopes

Abstract. The atmospheric He/N2 ratio is expected to increase due to the emission of He associated with fossil fuels and is expected to also vary in both space and time due to gravitational separation in the stratosphere. These signals may be useful indicators of fossil fuel exploitation and variability in stratospheric circulation, but direct measurements of He/N2 ratio are lacking on all timescales. Here we present a high-precision custom inlet system for mass spectrometers that continuously stabilizes the flow of gas during sample–standard comparison and removes all non-noble gases from the gas stream. This enables unprecedented accuracy in measurement of relative changes in the helium mole fraction, which can be directly related to the 4He/N2 ratio using supplementary measurements of O2/N2, Ar/N2 and CO2. Repeat measurements of the same combination of high-pressure tanks using our inlet system achieves a He/N2 reproducibility of ∼ 10 per meg (i.e., 0.001 %) in 6–8 h analyses. This compares to interannual changes of gravitational enrichment at ∼ 35 km in the midlatitude stratosphere of order 300–400 per meg and an annual tropospheric increase from human fossil fuel activity of less than ∼ 30 per meg yr−1 (bounded by previous work on helium isotopes). The gettering and flow-stabilizing inlet may also be used for the analysis of other noble-gas isotopes and could resolve previously unobserved seasonal cycles in Kr/N2 and Xe/N2.

Upwelling of Mantle Derived Material in Southeast China: Evidence from Noble Gas Isotopes

2021 ◽  
Author(s):  
Shuai WANG ◽  
Jian KUANG ◽  
Xuelian HUANG ◽  
Hongyan ZHANG ◽  
Min ZHANG ◽  
...  
Keyword(s):  
Noble Gas ◽  
Southeast China ◽  
Noble Gas Isotopes ◽  
Gas Isotopes

Noble gas isotopes in 25 000 years of hydrothermal fluids from 13°N on the East Pacific Rise

1995 ◽  
Vol 87 (1) ◽  
pp. 133-143 ◽  
Author(s):  
F. M. Stuart ◽  
P. J. Harrop ◽  
R. Knott ◽  
A. E. Fallick ◽  
G. Turner ◽  
...  
Keyword(s):  
Noble Gas ◽  
East Pacific Rise ◽  
Hydrothermal Fluids ◽  
East Pacific ◽  
Noble Gas Isotopes ◽  
Gas Isotopes

scholarly journals Deglacial water-table decline in Southern California recorded by noble gas isotopes

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Alan M. Seltzer ◽  
Jessica Ng ◽  
Wesley R. Danskin ◽  
Justin T. Kulongoski ◽  
Riley S. Gannon ◽  
...  
Keyword(s):  
Water Table ◽  
Southern California ◽  
Noble Gas ◽  
Water Table Depth ◽  
Last Deglaciation ◽  
Hydrological Change ◽  
Groundwater Levels ◽  
Surface Warming ◽  
Noble Gas Isotopes ◽  
Gas Isotopes

AbstractConstraining the magnitude of past hydrological change may improve understanding and predictions of future shifts in water availability. Here we demonstrate that water-table depth, a sensitive indicator of hydroclimate, can be quantitatively reconstructed using Kr and Xe isotopes in groundwater. We present the first-ever measurements of these dissolved noble gas isotopes in groundwater at high precision (≤0.005‰ amu−1; 1σ), which reveal depth-proportional signals set by gravitational settling in soil air at the time of recharge. Analyses of California groundwater successfully reproduce modern groundwater levels and indicate a 17.9 ± 1.3 m (±1 SE) decline in water-table depth in Southern California during the last deglaciation. This hydroclimatic transition from the wetter glacial period to more arid Holocene accompanies a surface warming of 6.2 ± 0.6 °C (±1 SE). This new hydroclimate proxy builds upon an existing paleo-temperature application of noble gases and may identify regions prone to future hydrological change.

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