东海近岸大气中的^(210)Po、^(210)Bi和^(210)Pb及其沉降入海通量评估  

Assessment of^(210)Po,210Bi and^(210)Pb in aerosols and their deposition fluxes in the nearshore region of the East China Sea

作　　者：马瑞阳 钟强强 王浩 杜娟 刘文靖 张洁然 黄德坤 于涛 Ma Ruiyang;Zhong Qiangqiang;Wang Hao;Du Juan;Liu Wenjing;Zhang Jieran;Huang Dekun;Yu Tao(College of Marine Sciences,Shanghai Ocean University,Shanghai 201306,China;Third Institute of Oceanography,Ministry of Nat-ural Resources,Xiamen 361005,China;State Key Laboratory of Estuarine and Coastal Research,East China Normal University,Shang-hai 200062,China;Research Centre for Eco-Environmental Engineering,Dongguan University of Technology,Dongguan 523808,China)

机构地区：[1]上海海洋大学海洋科学学院,上海201306 [2]自然资源部第三海洋研究所,福建厦门361005 [3]华东师范大学河口海岸学国家重点实验室,上海200062 [4]东莞理工学院生态环境工程技术研发中心,广东东莞523808

出　　处：《海洋学报》2024年第3期118-128,共11页

基　　金：国家自然科学基金项目(42206166,42107251);南海海洋资源利用国家重点实验室(海南大学)开放课题项目(MRUKF2021015)。

摘　　要：大气^(210)Po、^(210)Bi和^(210)Pb的沉降通量是海洋中核素示踪颗粒物动力学过程(颗粒有机碳输出、颗粒物输运)的基础参数,为揭示我国近海地区^(210)Po、^(210)Bi和^(210)Pb活度浓度的时空变化规律并估算其沉降入海通量,本文于2016年9月至翌年2月和2021年9-11月分别对上海及厦门地区近地表大气气溶胶中^(210)Po、^(210)Pb和^(210)Bi的活度浓度进行了连续观测;基于^(210)Po-^(210)Pb活度比(^(210)Po/^(210)Pb)和^(210)Bi-^(210)Pb活度比(^(210)Bi/^(210)Pb)两种示踪法计算了气溶胶颗粒物的滞留时间,并利用一维简单气溶胶沉降速率模型估算了3种核素以大气沉降方式输入东海的通量。结果显示,2016年上海秋、冬两季^(210)Po、^(210)Bi、^(210)Pb 3种核素活度浓度的变化范围分别为0.11~1.27 m Bq/m^(3)、0.45~1.83 m Bq/m^(3)和1.12~6.10 m Bq/m^(3);2021年秋季厦门^(210)Po、^(210)Bi、^(210)Pb 3种核素活度浓度的变化范围分别为0.05~0.85 m Bq/m^(3)、0.83~2.52 m Bq/m^(3)和0.17~1.32 m Bq/m^(3),上海近地表气溶胶中3种核素的活度浓度秋季平均值比厦门地区高。利用^(210)Po/^(210)Pb和^(210)Bi/^(210)Pb计算得到上海和厦门近地面大气的气溶胶滞留时间存在显著差异,基于^(210)Po/^(210)Pb计算上海气溶胶滞留时间均值为(94±54)d,基于^(210)Bi/^(210)Pb计算上海气溶胶滞留时间均值为(6.4±4.8)d,造成这种差异的原因很可能是两种示踪法本身具有的系统性差异。本文基于一维简易气溶胶沉降速率模型估算了上海地区的^(210)Pb、^(210)Bi和^(210)Po的大气沉降入东海的通量,其在秋季期间的变化范围分别为0.1~26.35 Bq/(m^(2)·d)、0.04~7.91 Bq/(m^(2)·d)和0.01~5.49 Bq/(m^(2)·d)。基于模型估算的^(210)Po、^(210)Bi和^(210)Pb沉降通量与研究区域的实际观测值接近一致,表明利用一维简易气溶胶沉降速率模型间接估算法在替代观测站直测核素的沉降入海通量方面具有一定可行性。The deposition fluxes of ^(210)Po,210Bi and ^(210)Pb in atmosphere are the basis for the application of radionuc-lide tracing in the ocean.In order to reveal the spatio-temporal variation of the activity of ^(210)Po,210Bi and ^(210)Pb in nearshore areas and estimate their deposition fluxes into the sea,in this paper,sampling observation and analysis of two typical areas near the East China Sea in Shanghai and Xiamen in different periods are carried out.A time series study was conducted on the the aerosol activities of ^(210)Po,^(210)Pb and ^(210)Bi in Shanghai and Xiamen from September 2016 to February 2017 and from September to November 2021,respectively.The residence time of aerosol particle was calculated based on ^(210)Po/^(210)Pb and ^(210)Bi/^(210)Pb.Deposition fluxes of three nuclides were also estimated.This pa-per reported the activity of ^(210)Po,210Bi and ^(210)Pb in Shanghai in autumn and winter of 2016.The activity ranges of ^(210)Po,^(210)Pb and ^(210)Bi were 0.11-1.27 mBq/m^(3),0.45-1.83 mBq/m^(3) and 1.12-6.10 mBq/m^(3),respectively.In the fall of 2021,the activity ranges of ^(210)Po,210Bi and ^(210)Pb in Xiamen were 0.05-0.85 mBq/m^(3),0.83-2.52 mBq/m^(3) and 0.17-1.32 mBq/m^(3),respectively.The aerosol activity of each nuclide in Shanghai was higher than that in Xiamen.The estimated residence time based on ^(210)Po-^(210)Pb and ^(210)Bi-^(210)Pb methods are significantly different,for example,in Shanghai area,the averaged aerosol residence time based on ^(210)Po-^(210)Pb method was calculated to be(94±54)d,which is much higher than the result from ^(210)Bi-^(210)Pb method.The main reason for this difference is most likely due to the difference in the properties of the tracing isotopes we used.In this paper,based on a one-dimensional simple aerosol deposition rate model,the atmospheric deposition fluxes of ^(210)Pb,210Bi and ^(210)Po over Shanghai area into the East China Sea are estimated,and their variation ranges are 0.1-26.35 Bq/(m^(2)·d),0.04-7.91 Bq/(m^(2)·d)and 0.01-5.49 Bq/(m^(2)·d),r

关 键 词：东海近岸 ^(210)Po ^(210)Bi ^(210)Pb 滞留时间 沉降入海通量 

分 类 号：P734.24[天文地球—海洋化学]