Analysis of the vertical radon structure at the Spanish "El Arenosillo" tower station. (January 2015)

• Record Type: Journal Article
• Authors: Vargas, A.; Arnold, D.; Adame, J.A.; Grossi, C.; Hernández-Ceballos, M.A.; Bolivar, J.P.
• Is Part Of: Journal of environmental radioactivity. Volume 139(2015:Jan.)
• Page Start: 1
• Page End: 17
• Publication Date: 2015-01
• Subjects: Outdoor 222Rn -- Atmospheric tracer -- Cluster -- Mixing height -- Tall tower; Radioactivity -- Periodicals; Radiation, Background -- Periodicals; Radioecology -- Periodicals; Radioactive pollution -- Periodicals; Environmental Pollutants -- Periodicals; Radioactive Pollutants -- Periodicals; Radioactivity -- Periodicals; Radioécologie -- Périodiques; Pollution radioactive -- Périodiques; Fond de rayonnement -- Périodiques; 539.752
• DOI: 10.1016/j.jenvrad.2014.09.018
• Languages: English
• ISSNs: 0265-931X

Abstract

Abstract: This paper presents an analysis of one year of hourly radon and meteorological measurements at 10 m and 100 m a.g.l. at El Arenosillo tall-tower station, in the south-west of the Iberian Peninsula. Whole-year and seasonal composites of the diurnal radon cycle show the expected behaviour, with larger concentrations at 10 m than at 100 m during the night, due to poor vertical mixing, and similar concentrations at both heights during the daylight hours. Wind speed and wind direction analyses by sector show the prevailing contributions for each season. Sectors with air which has spent a longer period over the ocean and high wind speeds will lead to low concentrations at both levels, whereas inland sectors show a clear increase of the concentrations with similar overall averages for the two levels. The Sierra Morena, Guadalquivir and Bethics System sectors (continental pathways) are the sectors that show higher concentrations for mild to large wind speeds. The daily evolution of radon concentration differences at both heights has been grouped into four clusters by using a K-means algorithm method. The four clusters have been selected so that they sufficiently describe different characteristics in terms of stability. The temporal evolution of the mixing height (MH) and of the bulk diffusivity parameter ( K b ) during the nocturnal period has been calculated by using the temporal variation of 222 Rn concentration at 10 m and the concentration gradient with height, respectively. Highlights: Radon concentration differences at both heights are grouped into four clusters. The four clusters describe different characteristics in terms of stability. We have statistically proven that there is no relation between clusters and seasons. Mixing height is calculated using the temporal variation of 222 Rn at 10 m. Bulk diffusivity is calculated using the concentration gradient with height.