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Journal ArticleDOI

One year of 222 Rn concentration in the atmospheric surface layer

19 Dec 2005-Atmospheric Chemistry and Physics (Copernicus GmbH)-Vol. 6, Iss: 10, pp 2865-2886
TL;DR: In this article, a one-year time series of radon measured in a rural area in the North of Italy in 1997 has been analyzed, where wavelet analysis is used as one of the investigation tools of the time series.
Abstract: A one-year time series of 222 Rn measured in a rural area in the North of Italy in 1997 is analyzed. The scope of the investigation is to better understand the behavior of this common atmospheric tracer in relation to the meteorological conditions at the release site. Wavelet analysis is used as one of the investigation tools of the time series. The measurements and scalograms of 222 Rn are compared to those of wind-speed, pressure, relative humidity, temperature and NO x . The use of wavelet analysis allows the identification of the various scales controlling the influence of the meteorological variables on 222 Rn dispersion in the surface layer that are not visible through classical Fourier analysis or direct time series inspection. The analysis of the time series has identified specific periods during which the usual diurnal variation of radon is superimposed to a linear growth thus indicating the build up of concentration at the measurement level. From these specific cases an estimate of the surface flux of 222 Rn is made. By means of a simple model these special cases are reproduced.

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Citations
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Journal ArticleDOI
TL;DR: In this paper, the authors synthesize the published literature on subsurface airflow driven by natural forcings such as atmospheric pressure fluctuations, topographic effect, water table fluctuations, and water infiltration.
Abstract: [1] Subsurface airflow in unsaturated zones induced by natural forcings is of importance in many environmental and engineering fields, such as environmental remediation, water infiltration and groundwater recharge, coastal soil aeration, mine and tunnel ventilation, and gas exchange between soil and atmosphere. This review synthesizes the published literature on subsurface airflow driven by natural forcings such as atmospheric pressure fluctuations, topographic effect, water table fluctuations, and water infiltration. The present state of knowledge concerning the mechanisms, analytical and numerical models, and environmental and engineering applications related to the naturally occurring airflow is discussed. Airflow induced by atmospheric pressure fluctuations is studied the most because of the applications to environmental remediation and transport of trace gases from soil to atmosphere, which are very important in understanding biogeochemical cycling and global change. Airflow induced by infiltration is also an extensively investigated topic because of its implications in rainfall infiltration and groundwater recharge. Airflow induced by water table fluctuations is important in coastal areas because it plays an important role in coastal environmental remediation and ecological systems. Airflow induced by topographic effect is studied the least. However, it has important applications in unsaturated zone gas transport and natural ventilation of mines and tunnels. Finally, the similarities and differences in the characteristics of the air pressure and airflow are compared and future research efforts are recommended.

88 citations


Cites background from "One year of 222 Rn concentration in..."

  • ...In addition, both positive [Galmarini, 2006] and negative [Klusman and Jaacks, 1987; Schery et al., 1989; Hutter, 1996; Iakovleva and Ryzhakova, 2003; Smetanov a et al., 2010] correlations between radon concentration and atmospheric pressure were found....

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  • ...Some researchers stated that only sudden drops or increases of atmospheric pressure (of the order of 1.0–1.5 kPa) can affect the radon exhalation [Kataoka et al., 2003; Galmarini, 2006]....

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Journal ArticleDOI
TL;DR: In this article, the authors 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 "non-local" processes.
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 "non-local" 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.

77 citations

Journal ArticleDOI
TL;DR: The seasonality of indoor Rn concentration measured in Austria is investigated as a function of other factors that influence indoors Rn, with higher Rn levels in winter.

63 citations

Journal ArticleDOI
TL;DR: In this paper, a technique recently developed for stability classification using a research-quality dual-flow-loop two-filter radon detector is adapted for use with a commercially available radon-based stability monitor.

57 citations

Journal ArticleDOI
06 Sep 2016-Tellus B
TL;DR: One year of radon, benzene and carbon monoxide (CO) concentrations were analyzed to characterise the combined influences of variations in traffic density and meteorological conditions on urban air quality in Bern, Switzerland as mentioned in this paper.
Abstract: 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 ~0.90–0.96) and CO (r 2 ~0.88–0.98) 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. Keywords: radon, air quality, urban, atmospheric stability, traffic density, vehicle emissions (Published: 6 September 2016) Citation: Tellus B 2016, 68, 30967, http://dx.doi.org/10.3402/tellusb.v68.30967

42 citations


Cites background from "One year of 222 Rn concentration in..."

  • ...…of the ubiquitous surface-emitted passive tracer radon (e.g. Allegrini et al., 1994; Duenas et al., 1996; Perrino, 2001, 2012; Avino et al., 2003; Galmarini, 2006; Sesana et al., 2006; Chambers et al., 2011, 2015a, 2015b, 2016; Wang et al., 2013; Williams et al., 2013; Kondo et al., 2014; Pitari…...

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References
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Journal ArticleDOI
TL;DR: In this paper, a wavelet analysis of turbulent fluxes of scalars collected during the BEMA campaign at the Mediterranean Spanish coast has been carried out using wavelet techniques, with particular attention to the role of the Thermal Internal Boundary Layer (TIBL) in regulating the exchange processes with the overlying free atmosphere.
Abstract: Aircraft measurements of turbulent fluxes ofscalars collected during the BEMA campaignat the Mediterranean Spanish coast havebeen analysed using wavelet techniques. The analysis aimsat characterising the boundary-layerstructure present during a period ofthe campaign with particular attention to therole of the Thermal Internal Boundary Layer (TIBL) in regulatingthe exchange processes with the overlyingfree atmosphere. The analysis of the dataobtained by flying through the turbulentlayer reveals the presence of characteristicstructures as the aircraft crossesthe TIBL top. These occur in a specific space and scale range. Comparisons of the result of the analysisobtained for different types of scalarsgive evidence that the region correspondingto the detected scales can be identifiedwith the entrainment zone of the TIBL.

13 citations

Journal ArticleDOI
TL;DR: Atmospheric activity concentrations of 212Pb and short-lived 222Rndaughters, together with meteorological elements, have been observed continuously at three sites at Kamisaibara Village in Japan.
Abstract: Atmospheric activity concentrations of 212Pb and short-lived 222Rndaughters, together with meteorological elements, have been observed continuously atthree sites at Kamisaibara Village in Japan In addition, atmospheric activity concentrationof 222Rn, equilibrium-equivalent concentration of 222Rn and conditionsof the lower atmosphere were observed for three intensive observation periods at Akawase,one of the three sites in Kamisaibara Village The equilibrium-equivalent concentration of222Rn is almost the same as the atmospheric activity concentration of short-lived222Rn daughters

10 citations


"One year of 222 Rn concentration in..." refers background in this paper

  • ...…1972; Beck et al., 1979; Vinod Kumar et al., 1999; Sesana et al., 2003, 2005; Pearson and Moses, 1966; Marcazan et al., 1993, 1997; Kataoka et al., 2001, 2003), to characterize the turbulent diffusion properties of the lower atmospheric levels, and since some of its radio…...

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Journal ArticleDOI
TL;DR: In this paper, a Laplace transform of the form ∫0∞ e−λsK(s) ds (where 1/λ is the characteristic isotopic decay time) is the key element in the solution.
Abstract: The differences in isotopic decay rates have been used to determine information about time-dependent turbulent dispersion from steady-state measurements. Two approaches to this problem are presented. In the first we consider the problem of determining mean horizontal transport. The transport results from vertical turbulent dispersion coupled with a mean horizontal wind that has a vertical gradient. In the second we treat the problem of dispersion of a source material embedded in an infinite turbulent medium. With both methods a Laplace transform of the form ∫0∞ e−λsK(s) ds (where 1/λ is the characteristic isotopic decay time) is the key element in the solution. Application to atmospheric and oceanographic conditions are discussed.

8 citations


"One year of 222 Rn concentration in..." refers background in this paper

  • ...…al., 2001, 2003), to characterize the turbulent diffusion properties of the lower atmospheric levels, and since some of its radio nuclides have decay timescales comparable to that of turbulent transport in the ABL (e.g. Beran and Assaf, 1970; Druilhet and Fontan, 1973; Kris-5 tensen et al., 1997)....

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Book ChapterDOI
01 Jan 2001
TL;DR: These lecture notes are a review on wavelet techniques for analyzing and computing fully-developed turbulent flows, which correspond to the regime where nonlinear instabilities are dominant.
Abstract: These lecture notes are a review on wavelet techniques for analyzing and computing fully-developed turbulent flows, which correspond to the regime where nonlinear instabilities are dominant. The wavelet-based techniques we have been developing during the last decade are explained and the main results are presented. After introducing the continuous and discrete wavelet transforms we present classical and wavelet-based statistical diagnostics to study turbulent flows. We then present wavelet methods for extracting coherent vortices in two- and three-dimensional turbulent flows. Afterwards we present an adaptive wavelet solver for the two-dimensional Navier—Stokes equations and apply it to compute a time-developing turbulent mixing layer. Finally we draw some conclusions and present some perspectives for turbulence modelling.

8 citations


"One year of 222 Rn concentration in..." refers methods in this paper

  • ...Towards this purpose, a time series analysis is conducted by means of wavelets (Farge, 2000; Farge and Schneider, 2002)....

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Journal ArticleDOI
01 Apr 1973-Tellus A
TL;DR: In this article, the thoron (Rn 220 86 ) is used as a traceur for the mesure des echanges verticaux de quantite de matiere dans la couche de surface au voisinage du sol.
Abstract: Le thoron (Rn 220 86 ) est utilise comme traceur pour la mesure des echanges verticaux de quantite de matiere dans la couche de surface au voisinage du sol. Sa courte periode (54 s) et sa source naturelle au sol (dont l'homogeneite doit etre satisfaite sur une surface relativement restreinte) permet de simplifier l'equation de diffusion de la theorie K . On presente et compare differentes methodes de mesure des coefficients d'echange verticaux a partir des profils de repartition verticale du thoron. Ces coefficients de diffusion, deduits du thoron, peuvent, en raison de la courte periode de ce traceur, etre differents de ceux d'un element stable. Nous avons, en utilisant les resultats de la theorie statistique, explicite une relation entre le coefficient de diffusion K R mesure avec un traceur radioactif et le coefficient de diffusion correspondant a un traceur stable. Un modele numerique, dans lequel, on tient compte du temps de diffusion, permet de rendre compte de l'approximation que l'on fait en utilisant la theorie K classique. Experimentalement, le thoron a ete mesure de facon continue pendant 9 mois, a 9 niveaux, entre 0 et 15 m de hauteur au-dessus d'un terrain plat. Les resultats sont depouilles dans le cadre de la theorie K . On donne en particulier, les variations diurnes moyennes, avec z , des coefficients d'echange, les profils obtenus en fonction de la stabilite de l'air determines par le gradient thermique. On compare ces coefficients avec ceux de la quantite de mouvement, deduits du profil de vent. On obtient des differences qui peuvent etre attribuees a l'influence du temps de diffusion sur la determination des coefficients d'echanges de matiere. On compare aussi les coefficients obtenus avec le thoron avec ceux deduits des parametres electriques de l'air, mesures sur le meme site. DOI: 10.1111/j.2153-3490.1973.tb01605.x

8 citations


"One year of 222 Rn concentration in..." refers background in this paper

  • ...The sharp collapsing of concentration due to the rapid growth of the ABL between 09:00 a.m. and 02:00 p.m.; 4....

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  • ...A sudden increase of concentration due to the collapsing of the daytime ABL....

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  • ..., 2001, 2003), to characterize the turbulent diffusion properties of the lower atmospheric levels, and since some of its radio nuclides have decay timescales comparable to that of turbulent transport in the ABL (e.g. Beran and Assaf, 1970; Druilhet and Fontan, 1973; Kris5 tensen et al., 1997)....

    [...]

  • ...…al., 2001, 2003), to characterize the turbulent diffusion properties of the lower atmospheric levels, and since some of its radio nuclides have decay timescales comparable to that of turbulent transport in the ABL (e.g. Beran and Assaf, 1970; Druilhet and Fontan, 1973; Kris-5 tensen et al., 1997)....

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  • ...It has long been studied in the atmospheric boundary25 layer (ABL) as constantly emitted from the surface (e.g. Israël et al., 1966; Ikebe and ACPD 5, 12895–12937, 2005 222Rn concentration in the atmospheric surface layer S. Galmarini Title Page Abstract Introduction Conclusions References Tables Figures J I J I Back Close Full Screen / Esc Print Version Interactive Discussion EGU Shimo, 1972; Beck et al., 1979; Vinod Kumar et al., 1999; Sesana et al., 2003, 2005; Pearson and Moses, 1966; Marcazan et al., 1993, 1997; Kataoka et al., 2001, 2003), to characterize the turbulent diffusion properties of the lower atmospheric levels, and since some of its radio nuclides have decay timescales comparable to that of turbulent transport in the ABL (e.g. Beran and Assaf, 1970; Druilhet and Fontan, 1973; Kris-5 tensen et al., 1997)....

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