Modeling radon transport in dry, cracked soil

Holford, D.J.; Schery, Stephen D.; Wilson, John L.; Phillips, Fred M.

doi:10.1029/92jb01845

Cited by 67 publications

(42 citation statements)

References 18 publications

(29 reference statements)

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“…This is because input parameters are available to drive a simple model at regional scale and because, over time periods of about ten days or longer, the mean flux density is close to that calculated from diffusion (Schery et al, 1984). Neglecting short-term variability, though, means that instantaneous fluxes may differ from modelled fluxes by around a factor of two (Holford et al, 1993).…”

Section: Methodsmentioning

confidence: 99%

“…We restrict ourselves to a simple model, even though more sophisticated models are required to better reproduce dayto-day variations in radon flux (Holford et al, 1993). This is because input parameters are available to drive a simple model at regional scale and because, over time periods of about ten days or longer, the mean flux density is close to that calculated from diffusion (Schery et al, 1984).…”

Section: Methodsmentioning

confidence: 99%

“…Based on observed short-term fluctuations (Holford et al, 1993), this is estimated to be a random error contributing about a factor of two to the measurement uncertainty. This is large enough to be a significant contributor to the scatter across the entire data set.…”

Section: Map Limitationsmentioning

confidence: 99%

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A map of radon flux at the Australian land surface

et al. 2010

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Abstract.A time-dependent map of radon-222 flux density at the Australian land surface has been constructed with a spatial resolution of 0.05 • and temporal resolution of one month. Radon flux density was calculated from a simple model utilising data from national gamma-ray aerial surveys; modelled soil moisture, available from 1900 in near realtime; and maps of soil properties. The model was calibrated against a data set of accumulation chamber measurements, thereby constraining it with experimental data. A notable application of the map is in atmospheric mixing and transport studies which use radon as a tracer, where it is a clear improvement on the common assumption of uniform radon flux density.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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A map of radon flux at the Australian land surface

et al. 2010

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“…The penetration depth of barometric pressure fluctuations increases with the permeability of the medium. In very high permeability fractures and boreholes, this mechanism is more prominent and the pressure wave can penetrate to a large depth, in some cases down to depth of several hundred meters (Nilson et al, 1992;Holford et al, 1993). Rossabi (2006) presented a comprehensive review of this mechanism.…”

Section: Barometric Pumpingmentioning

confidence: 99%

The Importance of Advective Fluxes to Gas Transport Across the Earth-Atmosphere Interface: The Role of Thermal Convection

Nachshon¹,

Weisbrod²,

Dragila³

et al. 2011

Planet Earth 2011 - Global Warming Challenges and Opportunities for Policy and Practice

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“…Finally, radon's surface source function can be considered to be essentially random and uncorrelated with atmospheric processes operating on short temporal (e.g. Holford et al, 1993) and small spatial (e.g. Karstens et al, 2015) scales, so that averaging can be used effectively as a means of isolating effects of interest.…”

Section: Introductionmentioning

confidence: 99%

Radon as a tracer of atmospheric influences on traffic-related air pollution in a small inland city

Williams¹,

Chambers²,

Conen³

et al. 2016

Tellus B: Chemical and Physical Meteorology

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A B S T R A C T One year of radon, benzene and carbon monoxide (CO) concentrations were analysed to characterise the combined influences of variations in traffic density and meteorological conditions on urban air quality in Bern, Switzerland. A recently developed radon-based stability categorisation technique was adapted to account for seasonal changes in day length and reduction in the local radon flux due to snow/ice cover and high soil moisture. Diurnal pollutant cycles were shown to result from an interplay between variations in surface emissions (traffic density), the depth of the nocturnal atmospheric mixing layer (dilution) and local horizontal advection of cleaner air from outside the central urban/industrial area of this small compact inland city. Substantial seasonal differences in the timing and duration of peak pollutant concentrations in the diurnal cycle were attributable to changes in day length and the switching to/from daylight-savings time in relation to traffic patterns. In summer, average peak benzene concentrations (0.62 ppb) occurred in the morning and remained above 0.5 ppb for 2 hours, whereas in winter average peak concentrations (0.85 ppb) occurred in the evening and remained above 0.5 ppb for 9 hours. Under stable conditions in winter, average peak benzene concentrations (1.1 ppb) were 120% higher than for well-mixed conditions (0.5 ppb). By comparison, summertime peak benzene concentrations increased by 53% from well-mixed (0.45 ppb) to stable nocturnal conditions (0.7 ppb). An idealised box model incorporating a simple advection term was used to derive a nocturnal mixing length scale based on radon, and then inverted to simulate diurnal benzene and CO emission variations at the city centre. This method effectively removes the influences of local horizontal advection and stability-related vertical dilution from the emissions signal, enabling a direct comparison with hourly traffic density. With the advection term calibrated appropriately, excellent results were obtained, with high regression coefficients in spring and summer for both benzene (r 2 Â0.90Á0.96) and CO (r 2 Â0.88Á0.98) in the two highest stability categories. Weaker regressions in winter likely indicate additional contributions from combustion sources unrelated to vehicular emissions. Average vehicular emissions during daylight hours were estimated to be around 0.503 (542) kg km (2 h (1 for benzene (CO) in the Bern city centre.

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Modeling radon transport in dry, cracked soil

Cited by 67 publications

References 18 publications

A map of radon flux at the Australian land surface

A map of radon flux at the Australian land surface

The Importance of Advective Fluxes to Gas Transport Across the Earth-Atmosphere Interface: The Role of Thermal Convection

Radon as a tracer of atmospheric influences on traffic-related air pollution in a small inland city

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