The depositional fluxes of atmospheric polonium-210 were measured at one site in Xiamen from August 2001 to March 2002. With predominant marine air mass, the depositional fluxes of atmospheric polonium-210 ranged from...The depositional fluxes of atmospheric polonium-210 were measured at one site in Xiamen from August 2001 to March 2002. With predominant marine air mass, the depositional fluxes of atmospheric polonium-210 ranged from 0.01 to 0.09 Bq/（m^2· d）, with an average of 0.04 Bq/（m^2 · d）. The seasonal pattern showed elevated polonium-210 fluxes in summer and autumn rather than in winter. Atmospheric depositional fluxes of polonium-210 showed a good correlation with beryllium-7 （r^2 =0. 85） and lead-210 fluxes （r^2 =0.71 ）, indicating their similar removal mechanism from atmosphere. The relationship between the polonium-210 depositional fluxes and the precipitation amount demonstrated that the precipitation dominates the polonium-210 removal from the atmosphere. The observed high activity ratios of polonium-210 to lead-210 indicated the occurrence of excess polonium-210 in coastal atmosphere, which may originate from marine surface waters either by indirect （foam）, or mare likely, direct （ air - sea exchange） input of marine bingenic material into the atmosphere. This source is even more important than the in situ decay of lead-210.展开更多
基金This research was supported by the National Natural Science Foundation of China under contract No.90411016the National Key Basic Research Special Foundation Program of China under contract No.2005CB422305China 0cean Mineral Resources Research and Development Association Foundation under contract Nos DY105-02-04 and DY105-02-01.
文摘The depositional fluxes of atmospheric polonium-210 were measured at one site in Xiamen from August 2001 to March 2002. With predominant marine air mass, the depositional fluxes of atmospheric polonium-210 ranged from 0.01 to 0.09 Bq/（m^2· d）, with an average of 0.04 Bq/（m^2 · d）. The seasonal pattern showed elevated polonium-210 fluxes in summer and autumn rather than in winter. Atmospheric depositional fluxes of polonium-210 showed a good correlation with beryllium-7 （r^2 =0. 85） and lead-210 fluxes （r^2 =0.71 ）, indicating their similar removal mechanism from atmosphere. The relationship between the polonium-210 depositional fluxes and the precipitation amount demonstrated that the precipitation dominates the polonium-210 removal from the atmosphere. The observed high activity ratios of polonium-210 to lead-210 indicated the occurrence of excess polonium-210 in coastal atmosphere, which may originate from marine surface waters either by indirect （foam）, or mare likely, direct （ air - sea exchange） input of marine bingenic material into the atmosphere. This source is even more important than the in situ decay of lead-210.
