Measurements of atmospheric Delta(CO2)-C-14 along the R/V Xuelong cruise track from Zhongshan Station (Antarctica) to Shanghai

During January-March 2011, 29 atmospheric Delta(14)CO(2 )samples were measured along the R/V Xuelong cruise track from Zhongshan Station (69.37 degrees S, 76.38 degrees E; Antarctica) to Shanghai. The extent of fossil fuel contamination in the samples was evaluated by comparison with contemporary hemispheric-scale averages of Delta(CO2 )-C-14, together with transport analysis and consideration of the delta(CO2)-C-13 levels in the samples. Generally, the A 14CO2 levels along the route south to 40.67 degrees S were lower than the hemispheric-scale average. Circumpolar deep water (CDW) upwelling, stratosphere-troposphere transport (STT), and region al transport associated with the Fukushima nuclear power plant (NPP) accident in Japan on 12 March 2011 were found to have influenced Delta(14)CO(2 )levels at the sampling sites. In comparison with the atmospheric Delta(14)CO(2 )level (45.7 +/- 3.5 parts per thousand (1 sigma) measured in the coastal region of East Antarctica, CDW upwelling caused reduction of -10L in Delta(14)CO(2 )in two cross sections: 62.0 degrees-64.0 degrees S along 74.0 degrees E and 51.7 degrees-54.0 degrees S along 80.5 degrees-84.0 degrees E. Conversely, STT-enhanced A 14CO2 was -7 parts per thousand (similar to 3L) at Zhongshan (around 45.0 degrees S). The linkage was supported by a certain Model-3/CMAQ simulation that indicated dispersion of radionuclides from the Fukushima NPP accident over the East Asian region, which explained the individual high Delta(CO2 )-C-14(52 parts per thousand) level on 29 March 2011 in Shanghai.