An estimate of the global distribution of radon emissions from the ocean

Schery, Stephen D.; Shi, Haiyang

doi:10.1029/2004gl021051

Cited by 62 publications

(72 citation statements)

References 12 publications

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“…Focusing on ocean areas reduces uncertainties in the model results: The diurnal temperature cycle is weaker over the oceans than over land (Seidel et al, 2005), hence using daily long term mean temperatures yields a smaller error over oceans compared with land. Oceans are also only weak sources of radon (Schery and Huang, 2004) and of ammonia (Dentener and Crutzen, 1994) compared with land masses, and hence neglecting their effect on ion production and nucleation is more appropriate over the oceans than over continents. Nonetheless, ammonia and radon are transported from land over the oceans where they can aid nucleation, which we do not account for.…”

Section: Modelmentioning

confidence: 99%

Aerosol nucleation over oceans and the role of galactic cosmic rays

et al. 2006

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Abstract. We investigate formation of sulfate aerosol in the marine troposphere from neutral and charged nucleation of H 2 SO 4 and H 2 O. A box model of neutral and charged aerosol processes is run on a grid covering the oceans. Input data are taken from a model of galactic cosmic rays in the atmosphere, and from global chemistry and transport models. We find a weak aerosol production over the tropical oceans in the lower and middle troposphere, and a stronger production at higher latitudes, most notably downwind of industrial regions. The strongest aerosol production however occurs in the upper troposphere over areas with frequent convective activity, in particular in the tropics. This finding supports the proposition by which non-sea salt marine boundary layer aerosol in tropical regions does not form in situ, but nucleates in the upper troposphere from convectively lifted and cloud processed boundary layer air rich in aerosol precursor gases, from where it descends in subsiding air masses compensating convection. Convection of boundary layer air also appears to drive the formation of condensation nuclei in the tropical upper troposphere which maintains the stratospheric aerosol layer in the absence of volcanic activity. Neutral nucleation contributes only marginally to aerosol production in our simulations. This highlights the importance of other mechanisms, including charged binary and ternary, and neutral ternary nucleation for aerosol formation. Our analysis indicates that the variation of ionization by galactic cosmic rays over the decadal solar cycle does not entail a response in aerosol production and cloud cover via the second indirect aerosol effect that would explain observed variations in global cloud cover. We estimate that the variation in radiative forcing resulting from a response of clouds to the change in galactic cosmic ray ionization and subsequent aerosol production over the decadal solar cycle is smaller than the concurrent variation of total solar irradiance.

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Section: Modelmentioning

confidence: 99%

Aerosol nucleation over oceans and the role of galactic cosmic rays

et al. 2006

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“…Radon is an unreactive, poorly soluble, radioactive gas (t 0.5 = 3.82d) that is emitted naturally from ice-free, unsaturated terrestrial surfaces at a rate that varies slowly both geographically and temporally (0.72-1.2 atoms cm −2 s −1 ; Turekian et al, 1977;Lambert et al, 1982;Jacob et al, 1997) and is two orders of magnitude greater than from open bodies of water (Wilkening and Clements, 1975;Schery and Huang, 2004). The half-life of radon is sufficiently long that it can be assumed to be an approximately conservative tracer over the course of a single night, while being short enough that it does not accumulate in the atmosphere and typically exhibiting an order of magnitude gradient between the atmospheric boundary layer (ABL) and the lower troposphere.…”

Section: Introductionmentioning

confidence: 99%

On the use of radon for quantifying the effects of atmospheric stability on urban emissions

et al. 2015

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Abstract.Radon is increasingly being used as a tool for quantifying stability influences on urban pollutant concentrations. Bulk radon gradients are ideal for this purpose, since the vertical differencing substantially removes contributions from processes on timescales greater than diurnal and (assuming a constant radon source) gradients are directly related to the intensity of nocturnal mixing. More commonly, however, radon measurements are available only at a single height. In this study we argue that single-height radon observations should not be used quantitatively as an indicator of atmospheric stability without prior conditioning of the time series to remove contributions from larger-scale "nonlocal" processes. We outline a simple technique to obtain an approximation of the diurnal radon gradient signal from a single-height measurement time series, and use it to derive a four category classification scheme for atmospheric stability on a "whole night" basis. A selection of climatological and pollution observations in the Sydney region are then subdivided according to the radon-based scheme on an annual and seasonal basis. We compare the radon-based scheme against a commonly used Pasquill-Gifford (P-G) type stability classification and reveal that the most stable category in the P-G scheme is less selective of the strongly stable nights than the radon-based scheme; this lead to significant underestimation of pollutant concentrations on the most stable nights by the P-G scheme. Lastly, we applied the radon-based classification scheme to mixing height estimates calculated from the diurnal radon accumulation time series, which provided insight to the range of nocturnal mixing depths expected at the site for each of the stability classes.

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“…Apart from local mineralogy and element composition of the soil, continental emission rates depend on soil texture and soil humidity and typically range between 0.005 and 0.050 Bq m −2 s −1 (Nazaroff, 1992;Karstens et al, 2013), about two orders of magnitude higher than oceanic emissions (e.g. Schery and Huang, 2004). For the latter a recent study derived from long-term 222 Rn observation at Cape Grim (Tasmania) an oceanic 222 Rn emission rate of around 2.7 × 10 −4 Bq m −2 s −1 .…”

Section: Introductionmentioning

confidence: 99%

On the variability of atmospheric <sup>222</sup>Rn activity concentrations measured at Neumayer, coastal Antarctica

et al. 2014

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Abstract. We report on continuously measured 222 Rn activity concentrations in near-surface air at Neumayer Station in the period 1995-2011. This 17-year record showed no long-term trend and has overall mean ± standard deviation of (0.019 ± 0.012) Bq m −3 . A distinct and persistent seasonality could be distinguished with maximum values of (0.028 ± 0.013) Bq m −3 from January to March and minimum values of (0.015 ± 0.009) Bq m −3 from May to October. Elevated 222 Rn activity concentrations were typically associated with air mass transport from the Antarctic Plateau. Our results do not support a relation between enhanced 222 Rn activity concentrations at Neumayer and cyclonic activity or long-range transport from South America. The impact of oceanic 222 Rn emissions could not be properly assessed but we tentatively identified regional sea ice extent (SIE) variability as a significant driver of the annual 222 Rn cycle.

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An estimate of the global distribution of radon emissions from the ocean

Cited by 62 publications

References 12 publications

Aerosol nucleation over oceans and the role of galactic cosmic rays

Aerosol nucleation over oceans and the role of galactic cosmic rays

On the use of radon for quantifying the effects of atmospheric stability on urban emissions

On the variability of atmospheric <sup>222</sup>Rn activity concentrations measured at Neumayer, coastal Antarctica

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An estimate of the global distribution of radon emissions from the ocean

Cited by 62 publications

References 12 publications

Aerosol nucleation over oceans and the role of galactic cosmic rays

Aerosol nucleation over oceans and the role of galactic cosmic rays

On the use of radon for quantifying the effects of atmospheric stability on urban emissions

On the variability of atmospheric &lt;sup&gt;222&lt;/sup&gt;Rn activity concentrations measured at Neumayer, coastal Antarctica

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On the variability of atmospheric <sup>222</sup>Rn activity concentrations measured at Neumayer, coastal Antarctica