Assessment of tropical OH seasonality using atmospheric <sup>14</sup>CO measurements from Barbados

Mak, J. E.; Southon, John

doi:10.1029/98gl02180

Cited by 26 publications

(18 citation statements)

References 21 publications

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“…Increasingly sophisticated models are being developed, and independent assessments of OH using independent tracers remain important. We note that concomitantly more measurements are becoming available [Mak and Southon, 1998]. …”

Section: Discussionmentioning

confidence: 99%

Simulations of cosmogenic ¹⁴CO using the three‐dimensional atmospheric model MATCH: Effects of ¹⁴C production distribution and the solar cycle

1999

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Section: Discussionmentioning

confidence: 99%

Simulations of cosmogenic ¹⁴CO using the three‐dimensional atmospheric model MATCH: Effects of ¹⁴C production distribution and the solar cycle

1999

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“…(solid line, right axis) 14 C production rate calculated from the shielding potential as described in (Lowe and Allan, 2002). compounds (VOCs) or direct emission from biomass burning (Bergamaschi et al, 2001;Brenninkmeijer, 1993;Mak and Southon, 1998). To account for this recycled fraction in the measurements, we simulated 14 C-free CO from direct fossil emissions and from oxidation of fossil CH 4 .…”

Section: Model Descriptionmentioning

confidence: 99%

“…For instance, the seasonal variation of 14 CO at high latitudes clearly signals the oxidizing action of OH in the local summer season. The lower mixing ratios in the tropics are caused by the higher abundance of OH in the tropics, and by the larger distance from the main 14 CO production region (Jöckel et al, 2000;Mak and Southon, 1998).…”

Section: Introductionmentioning

confidence: 99%

“…In contrast to longer-lived species like MCF, this means that a specific 14 CO measurement is sensitive to OH within a smaller region of influence. Thus, information on regional OH can be obtained, given an accurate description of the transport from the production regions to the measurement sites (Volz et al, 1981;Jöckel et al, 2000;Mak and Southon, 1998). Whereas this constraint on regional OH is in principle clear, it has never been quantified.…”

Section: Introductionmentioning

confidence: 99%

“…two months. Measurements in the atmosphere may therefore be used to indirectly estimate the abundance of OH Mak et al, 1992;Mak and Southon, 1998;Manning et al, 2005;Volz et al, 1981). For instance, the seasonal variation of 14 CO at high latitudes clearly signals the oxidizing action of OH in the local summer season.…”

Section: Introductionmentioning

confidence: 99%

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What can <sup>14</sup>CO measurements tell us about OH?

et al. 2008

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Abstract. The possible use of 14 CO measurements to constrain hydroxyl radical (OH) concentrations in the atmosphere is investigated. 14 CO is mainly produced in the upper atmosphere from cosmic radiation. Measurements of 14 CO at the surface show lower concentrations compared to the upper atmospheric source region, which is the result of oxidation by OH. In this paper, the sensitivity of 14 CO mixing ratio surface measurements to the 3-D OH distribution is assessed with the TM5 model. Simulated 14 CO mixing ratios agree within a few molecules 14 CO cm −3 (STP) with existing measurements at five locations worldwide. The simulated cosmogenic 14 CO distribution appears mainly sensitive to the assumed upper atmospheric 14 C source function, and to a lesser extend to model resolution. As a next step, the sensitivity of 14 CO measurements to OH is calculated with the adjoint TM5 model. The results indicate that 14 CO measurements taken in the tropics are sensitive to OH in a spatially confined region that varies strongly over time due to meteorological variability. Given measurements with an accuracy of 0.5 molecules 14 CO cm −3 STP, a good characterization of the cosmogenic 14 CO fraction, and assuming perfect transport modeling, a single 14 CO measurement may constrain OH to 0.2-0.3×10 6 molecules OH cm −3 on time scales of 6 months and spatial scales of 70×70 degrees (latitude×longitude) between the surface and 500 hPa. The sensitivity of 14 CO measurements to high latitude OH is about a factor of five higher. This is in contrast with methyl chloroform (MCF) measurements, which show the highest sensitivity to tropical OH, Correspondence to: M. C. Krol (m.c.krol@uu.nl) mainly due to the temperature dependent rate constant of the MCF-OH reaction. A logical next step will be the analysis of existing 14 CO measurements in an inverse modeling framework. This paper presents the required mathematical framework for such an analysis.

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Impacts of global emissions of CO, NO x , and CH4 on China tropospheric hydroxyl free radicals

Lin

Fan³

et al. 2012

Adv. Atmos. Sci.

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Using the global chemistry and transport model MOZART, the simulated distributions of tropospheric hydroxyl free radicals (OH) over China and its sensitivities to global emissions of carbon monoxide (CO), nitrogen oxide (NOx), and methane (CH4) were investigated in this study. Due to various distributions of OH sources and sinks, the concentrations of tropospheric OH in east China are much greater than in west China. The contribution of NO + perhydroxyl radical (HO2) reaction to OH production in east China is more pronounced than that in west China, and because of the higher reaction activity of non-methane volatile organic compounds (NMVOCs), the contributions to OH loss by NMVOCs exceed those of CO and take the dominant position in summer. The results of the sensitivity runs show a significant increase of tropospheric OH in east China from 1990 to 2000, and the trend continues. The positive effect of double emissions of NOx on OH is partly offset by the contrary effect of increased CO and CH4 emissions: the double emissions of NOx will cause an increase of OH of 18.1%-30.1%, while the increases of CO and CH4 will cause a decrease of OH of 12.2%-20.8% and 0.3%-3.0%, respectively. In turn, the lifetimes of CH4, CO, and NOx will increase by 0.3%-3.1% with regard to double emissions of CH4, 13.9%-26.3% to double emissions of CO and decrease by 15.3%-23.2% to double emissions of NOx.

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Assessment of tropical OH seasonality using atmospheric ¹⁴CO measurements from Barbados

Abstract: Abstract

Cited by 26 publications

References 21 publications

Simulations of cosmogenic ¹⁴CO using the three‐dimensional atmospheric model MATCH: Effects of ¹⁴C production distribution and the solar cycle

Simulations of cosmogenic ¹⁴CO using the three‐dimensional atmospheric model MATCH: Effects of ¹⁴C production distribution and the solar cycle

What can <sup>14</sup>CO measurements tell us about OH?

Impacts of global emissions of CO, NO x , and CH4 on China tropospheric hydroxyl free radicals

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Assessment of tropical OH seasonality using atmospheric 14CO measurements from Barbados

Abstract: Abstract

Cited by 26 publications

References 21 publications

Simulations of cosmogenic 14CO using the three‐dimensional atmospheric model MATCH: Effects of 14C production distribution and the solar cycle

Simulations of cosmogenic 14CO using the three‐dimensional atmospheric model MATCH: Effects of 14C production distribution and the solar cycle

What can &lt;sup&gt;14&lt;/sup&gt;CO measurements tell us about OH?

Impacts of global emissions of CO, NO x , and CH4 on China tropospheric hydroxyl free radicals

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Resources

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Assessment of tropical OH seasonality using atmospheric ¹⁴CO measurements from Barbados

Simulations of cosmogenic ¹⁴CO using the three‐dimensional atmospheric model MATCH: Effects of ¹⁴C production distribution and the solar cycle

Simulations of cosmogenic ¹⁴CO using the three‐dimensional atmospheric model MATCH: Effects of ¹⁴C production distribution and the solar cycle

What can <sup>14</sup>CO measurements tell us about OH?