Dry and wet deposition of 7Be, 210Pb and 137Cs in Monaco air during 1998-2010: Seasonal variations of deposition fluxes

Temporal variations of Be-7, Pb-210 and Cs-137 activity concentrations in precipitation in Monaco from 1998 to 2010 showed that maxima of Be-7 and Pb-210 deposition fluxes coincide with the peaks of precipitation amounts observed in different months of a year, and most of Be-7 and Pb-210 was washout from the atmosphere by precipitation. The seasonal variations were not uniform from year to year, and the amount of precipitation controlled the deposition fluxes of Be-7 and Pb-210, which was not the case for Cs-137. The fractional deposition fluxes of Be-7 and Pb-210 in different seasons were in the order fall > spring > winter > summer, while the fractional amount of precipitation followed the order fall > winter > spring > summer. The fractional deposition fluxes of Cs-137 were found in the order spring > fall > summer > winter. The precipitation-normalized deposition fluxes of Be-7, Pb-210 and (CS)-C-137 were generally higher during summer. The highest Be-7/Pb-210 activity ratio was observed in 2010, and the smallest one in 2001, following the influence of the modulation of cosmic rays on the production rates of 7Be in the atmosphere by solar activity. Activity ratios of Be-7/Pb-210 observed in winter and fall were generally higher than during summer and spring. (c) 2012 Elsevier Ltd. All rights reserved.