北冰洋表层积雪中^(7)Be、^(210)Po和^(210)Pb的分布特征

Distribution characteristics of ^(7)Be,^(210)Po and ^(210)Pb in the surface snow of the Arctic Ocean

大气输送的放射性核素^(7)Be、^(210)Po和^(210)Pb,可以作为研究北冰洋大气沉降通量、海洋现代沉积以及海冰中物质传输的重要示踪剂,已被广泛应用于包括气团运动、土壤侵蚀以及水系统中颗粒物循环过程的研究。本文报道了2018年北极高纬度浮冰区表层积雪中^(7)Be、^(210)Po和^(210)Pb的活度特征。^(7)Be、^(210)Po和^(210)Pb的比活度变化范围分别为33.6~632.68 mBq/L、36.2~87.5 mBq/L、30.9~194.49 mBq/L。本文的研究发现,北冰洋表层积雪中^(7)Be和210Pb比活度小于中纬度大陆地区。研究区域表层积雪中^(7)Be的比活度随着纬度的增加而增加。此外,表层积雪中^(210)Po/^(210)Pb活度比值范围为0.70~1.48(平均为0.93),^(210)Po与^(210)Pb活度已基本达到平衡,表明积雪样品年龄可能较“老”。

The radionuclides ^(7)Be,^(210)Po and ^(210)Pb transported by the atmosphere can be used as important tracers for studying the material deposition flux of the Arctic Ocean’s atmosphere,modern ocean sedimentation and the transport of materials into the sea ice.They have been widely used in the study of air mass movement,soil erosion,and particle circulation processes in water systems.This paper reports the activities of ^(7)Be,^(210)Po and ^(210)Pb in the surface snow of the high-latitude ice floes of the Arctic Ocean in 2018.The activity concentrations of ^(7)Be,^(210)Po and ^(210)Pb are 33.6−632.68 mBq/L,36.2−87.5 mBq/L,and 30.9−194.49 mBq/L,respectively.The activity concentrations of ^(7)Be and ^(210)Pb in the surface snow of the Arctic Ocean are lower than those in the mid-latitude continental areas.The results show that the activity concentrations of 7Be in snow increased with the increase of latitude.The activity ratio of ^(210)Po/^(210)Pb ranged from 0.70 to 1.48(with an average of 0.93),^(210)Po is almost in equilibrium with ^(210)Pb.It indicates that the age of the surface snow is“older”.