Molecular hydrogen in the troposphere: Global distribution and budget

Novelli, P. C.; Lang, P. M.; Masarie, K. A.; Hurst, D. F.; Myers, R. C.; Elkins, James W.

doi:10.1029/1999jd900788

Cited by 319 publications

(560 citation statements)

References 63 publications

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“…This may affect the atmosphere's oxidative capacity and stratospheric ozone levels (Schultz et al, 2003;Warwick et al, 2004;Tromp et al, 2003;Feck et al, 2008). A number of global H 2 budget estimates have been made (Novelli et al, 1999;Hauglustaine and Ehhalt, 2002;Sanderson et al, Bousquet et al, 2011;Pieterse et al, 2011Pieterse et al, , 2012. These estimates agree that the largest source of H 2 to the atmosphere is oxidation of hydrocarbons, followed by combustion of fossil fuels and biomass (see Table 1).…”

Section: Atmospheric Molecular Hydrogen (H 2 )mentioning

confidence: 99%

“…These source terms are balanced by two sink processes, uptake by soils (and subsequent destruction by enzymes) and atmospheric oxidation by the hydroxyl radical (OH), of which soil uptake is the largest. Together, these processes result in typical atmospheric H 2 mixing ratios (χ (H 2 )) of around 547 ppb (nmole/mole) at ground level (Novelli et al, 1999, converted to the latest χ(H 2 ) scale established by Jordan and Steinberg (2011)), with on average 3% higher values in the Southern Hemisphere. Model results indicate that χ (H 2 ) may increase slightly with height, especially in the Northern Hemisphere extratropics (Hauglustaine and Ehhalt, 2002;Price et al, 2007;Pieterse et al, 2011).…”

Section: Atmospheric Molecular Hydrogen (H 2 )mentioning

confidence: 99%

“…b Walter et al (2011) found this source signature to be (−741±13) ‰. c Novelli et al (1999) d Depending on latitude, Batenburg et al (2011) be one of the main processes that enrich the global tropospheric H 2 reservoir. Both Price et al (2007) and Pieterse et al (2011) estimated that STE contributes several tens of ‰ to the global tropospheric δD average.…”

Section: Stable Isotope Studies Of Hmentioning

confidence: 99%

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The stable isotopic composition of molecular hydrogen in the tropopause region probed by the CARIBIC aircraft

et al. 2012

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Abstract. More than 450 air samples that were collected in the upper troposphere -lower stratosphere (UTLS) region by the CARIBIC aircraft (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) have been analyzed for molecular hydrogen (H 2 ) mixing ratios (χ (H 2 )) and H 2 isotopic composition (deuterium content, δD).More than 120 of the analyzed samples contained air from the lowermost stratosphere (LMS). These show that χ(H 2 ) does not vary appreciably with O 3 -derived height above the thermal tropopause (TP), whereas δD does increase with height. The isotope enrichment is caused by H 2 production and destruction processes that enrich the stratospheric H 2 reservoir in deuterium (D); the exact shapes of the profiles are mainly determined by mixing of stratospheric with tropospheric air. Tight negative correlations are found between δD and the mixing ratios of methane (χ(CH 4 )) and nitrous oxide (χ (N 2 O)), as a result of the relatively long lifetimes of these three species. Samples that were collected from the Indian subcontinent up to 40 • N before, during and after the summer monsoon season show no significant seasonal change in χ(H 2 ), but δD is up to 12.3 ‰ lower in the July, August and September monsoon samples. This δD decrease is correlated with the χ(CH 4 ) increase in these samples. The significant correlation with χ (CH 4 ) and the absence of a perceptible χ(H 2 ) increase that accompanies the δD decrease indicates that microbial production of very D-depleted H 2 in the wet season may contribute to this phenomenon.Some of the samples have very high χ (H 2 ) and very low δD values, which indicates a pollution effect. Aircraft engine exhaust plumes are a suspected cause, since the effect mostly occurs in samples collected close to airports, but no similar signals are found in other chemical tracers to support this. The isotopic source signature of the H 2 pollution seems to be on the low end of the signature for fossil fuel burning.

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Section: Atmospheric Molecular Hydrogen (H 2 )mentioning

confidence: 99%

Section: Atmospheric Molecular Hydrogen (H 2 )mentioning

confidence: 99%

Section: Stable Isotope Studies Of Hmentioning

confidence: 99%

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The stable isotopic composition of molecular hydrogen in the tropopause region probed by the CARIBIC aircraft

et al. 2012

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“…H 2 is scavenged by the hydroxyl radical (OH radical), thereby attenuating the ability of OH to scavenge potent greenhouse gases, like methane (CH 4 ) from the atmosphere, which classifies H 2 as an indirect greenhouse gas (Novelli et al, 1999). H 2 is also a significant source of water vapor to the stratosphere, and as such may adversely perturb stratospheric ozone chemistry (Solomon, 1999;Tromp et al, 2003;Warwick et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…H 2 is also a significant source of water vapor to the stratosphere, and as such may adversely perturb stratospheric ozone chemistry (Solomon, 1999;Tromp et al, 2003;Warwick et al, 2004). The two major atmospheric H 2 sources are photochemical production from methane and non-methane hydrocarbons and combustion of fossil fuels and biomass (Novelli et al, 1999). The major H 2 sinks are soil consumption, representing about 81 ± 8 % of the total sink, and oxidation by OH being about 17 ± 3 % based on a global inversion of sparse atmospheric H 2 measurements (Xiao et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Ecosystem fluxes of hydrogen: a comparison of flux-gradient methods

et al. 2014

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Abstract. Our understanding of biosphere-atmosphere exchange has been considerably enhanced by eddy covariance measurements. However, there remain many trace gases, such as molecular hydrogen (H 2 ), that lack suitable analytical methods to measure their fluxes by eddy covariance. In such cases, flux-gradient methods can be used to calculate ecosystem-scale fluxes from vertical concentration gradients. The budget of atmospheric H 2 is poorly constrained by the limited available observations, and thus the ability to quantify and characterize the sources and sinks of H 2 by fluxgradient methods in various ecosystems is important. We developed an approach to make nonintrusive, automated measurements of ecosystem-scale H 2 fluxes both above and below the forest canopy at the Harvard Forest in Petersham, Massachusetts, for over a year. We used three flux-gradient methods to calculate the fluxes: two similarity methods that do not rely on a micrometeorological determination of the eddy diffusivity, K, based on (1) trace gases or (2) sensible heat, and one flux-gradient method that (3) parameterizes K. We quantitatively assessed the flux-gradient methods using CO 2 and H 2 O by comparison to their simultaneous independent flux measurements via eddy covariance and soil chambers. All three flux-gradient methods performed well in certain locations, seasons, and times of day, and the best methods were trace gas similarity for above the canopy and K parameterization below it. Sensible heat similarity required several independent measurements, and the results were more variable, in part because those data were only available in the winter, when heat fluxes and temperature gradients were small and difficult to measure. Biases were often observed between flux-gradient methods and the independent flux measurements, and there was at least a 26 % difference in nocturnal eddy-derived net ecosystem exchange (NEE) and chamber measurements. H 2 fluxes calculated in a summer period agreed within their uncertainty and pointed to soil uptake as the main driver of H 2 exchange at Harvard Forest, with H 2 deposition velocities ranging from 0.04 to 0.10 cm s −1 .

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Remote determinations on fumarole outlet temperatures in an eruptive volcano

Tsunogai

Cheng

Ito

et al. 2016

Geophysical Research Letters

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Direct measurement of the fumarole outlet temperature in active volcanoes is impractical. Therefore, we used an aircraft to sample H2 in the volcanic plume ejected from Sakurajima volcano to remotely estimate the highest fumarolic temperatures of the volcano based on hydrogen isotopic fractionation between H2 and magmatic H2O. We successfully estimated that the δD of the fumarolic H2 in September and December 2014 was −135 ± 13‰ and −113 ± 11‰, respectively, and that the corresponding highest outlet temperatures were 1050 ± 120°C and 1199 ± 139°C. Although the temperatures were higher than those determined by using infrared remote sensing, we concluded that they are more reliable estimates of the highest fumarole outlet temperatures. Combined with plume sampling by using aircraft, remote temperature sensing based on the δD of H2 in volcanic plumes can be widely applied to active volcanoes to determine the highest fumarole outlet temperatures.

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Molecular hydrogen in the troposphere: Global distribution and budget

Cited by 319 publications

References 63 publications

The stable isotopic composition of molecular hydrogen in the tropopause region probed by the CARIBIC aircraft

The stable isotopic composition of molecular hydrogen in the tropopause region probed by the CARIBIC aircraft

Ecosystem fluxes of hydrogen: a comparison of flux-gradient methods

Remote determinations on fumarole outlet temperatures in an eruptive volcano

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