2011-03-11日本福岛核电站放射性物质发生泄漏事件,本研究基于MASNUM(Laboratory of Marine Science and Numerical Modeling)海洋环流模式,建立了西北太平洋海洋放射性物质输运扩散模式,对事故释放的^(137)Cs在海洋中的输运和扩散过程...2011-03-11日本福岛核电站放射性物质发生泄漏事件,本研究基于MASNUM(Laboratory of Marine Science and Numerical Modeling)海洋环流模式,建立了西北太平洋海洋放射性物质输运扩散模式,对事故释放的^(137)Cs在海洋中的输运和扩散过程进行了20a的模拟与预测。根据与观测资料的比较,验证了所建立的模式具备模拟放射性物质在海洋中的输运扩散过程的能力。结果显示:至2015年,^(137)Cs表层活度浓度已经扩散至整个中国海域,活度浓度值在0.01Bq/m^3左右;事故发生10a后,研究海域^(137)Cs表层活度浓度趋于均匀,为0.20~0.60Bq/m^3左右;20a后,^(137)Cs在海洋表层的活度浓度要小于0.15Bq/m^3。垂向扩散的结果显示:事故发生10a后,黄海海域^(137)Cs垂向分布较为均匀,东海东部陆架海域活度浓度高于西部海域,且上层海水中^(137)Cs活度浓度高于底层海水,南海北部海域^(137)Cs活度浓度高于南部海域,且略小于黄海和东海;至2030年,中国近海^(137)Cs的活度浓度的垂向分布趋于均匀,南海略高于黄海和东海;日本海^(137)Cs活度浓度主要集中在表层,最大活度浓度出现在2016年,约为0.20Bq/m^3;西北太平洋海域^(137)Cs活度浓度要高于其他4个海域;2030年以后,整个海域^(137)Cs活度浓度在水平和垂向分布均趋于均匀,均小于0.15Bq/m^3。展开更多
Seven cores were collected from different sediment zones of tidal flats at Xin- yanggang in north Jiangsu province in August 2007. Sediment grain-size distribution and radioisotopes of ^137Cs and ^210Ppb analysis were...Seven cores were collected from different sediment zones of tidal flats at Xin- yanggang in north Jiangsu province in August 2007. Sediment grain-size distribution and radioisotopes of ^137Cs and ^210Ppb analysis were carried out for these cores. Sediment rates of the cores and radioisotopes distribution in surface sediment in different zones of the tidal flat were calculated from the ^137Cs and ^210Ppb activities in sediments cores. The results indicated that each tidal zone had experienced different evolution phases, hydrological dynamics in the tidal flats made the grain-size of the surface sediment change gradually. ^137Cs and ^210Ppb activities on the superficial layer of the cores varied spatially and the reason was discussed. On tidal flats, the fluctuation of ^137Cs and ^210Ppb activities in the cores reflected the special sedimentary characteristics. Vegetation affects the grain-size distribution and the vertical profiles of ^137Cs and ^210Ppb in the upper depths. ^137Cs and ^210Ppb chronology got the comparable average sediment rates on the tidal flat. The characteristics of ^137Cs and ^210Ppb in the cores reflected various depositional dynamical environments in different tidal zones and gave information on the different evolvement phases of the tidal zones. Based on the information of grain-size distribution, texture of the cores, sediment rates and topography, the evolution lines of the tidal flat were reconstructed.展开更多
文摘2011-03-11日本福岛核电站放射性物质发生泄漏事件,本研究基于MASNUM(Laboratory of Marine Science and Numerical Modeling)海洋环流模式,建立了西北太平洋海洋放射性物质输运扩散模式,对事故释放的^(137)Cs在海洋中的输运和扩散过程进行了20a的模拟与预测。根据与观测资料的比较,验证了所建立的模式具备模拟放射性物质在海洋中的输运扩散过程的能力。结果显示:至2015年,^(137)Cs表层活度浓度已经扩散至整个中国海域,活度浓度值在0.01Bq/m^3左右;事故发生10a后,研究海域^(137)Cs表层活度浓度趋于均匀,为0.20~0.60Bq/m^3左右;20a后,^(137)Cs在海洋表层的活度浓度要小于0.15Bq/m^3。垂向扩散的结果显示:事故发生10a后,黄海海域^(137)Cs垂向分布较为均匀,东海东部陆架海域活度浓度高于西部海域,且上层海水中^(137)Cs活度浓度高于底层海水,南海北部海域^(137)Cs活度浓度高于南部海域,且略小于黄海和东海;至2030年,中国近海^(137)Cs的活度浓度的垂向分布趋于均匀,南海略高于黄海和东海;日本海^(137)Cs活度浓度主要集中在表层,最大活度浓度出现在2016年,约为0.20Bq/m^3;西北太平洋海域^(137)Cs活度浓度要高于其他4个海域;2030年以后,整个海域^(137)Cs活度浓度在水平和垂向分布均趋于均匀,均小于0.15Bq/m^3。
基金National Basic Research Program of China, No.2002CB412401 Scientific Research Foundation of Graduate School of Nanjing University National Natural Science Foundation of China, No.40776023
文摘Seven cores were collected from different sediment zones of tidal flats at Xin- yanggang in north Jiangsu province in August 2007. Sediment grain-size distribution and radioisotopes of ^137Cs and ^210Ppb analysis were carried out for these cores. Sediment rates of the cores and radioisotopes distribution in surface sediment in different zones of the tidal flat were calculated from the ^137Cs and ^210Ppb activities in sediments cores. The results indicated that each tidal zone had experienced different evolution phases, hydrological dynamics in the tidal flats made the grain-size of the surface sediment change gradually. ^137Cs and ^210Ppb activities on the superficial layer of the cores varied spatially and the reason was discussed. On tidal flats, the fluctuation of ^137Cs and ^210Ppb activities in the cores reflected the special sedimentary characteristics. Vegetation affects the grain-size distribution and the vertical profiles of ^137Cs and ^210Ppb in the upper depths. ^137Cs and ^210Ppb chronology got the comparable average sediment rates on the tidal flat. The characteristics of ^137Cs and ^210Ppb in the cores reflected various depositional dynamical environments in different tidal zones and gave information on the different evolvement phases of the tidal zones. Based on the information of grain-size distribution, texture of the cores, sediment rates and topography, the evolution lines of the tidal flat were reconstructed.
