高空核试验放射性烟云扩散的数值模拟研究  

Numerical simulation research on the radioactive plume diffusion led by nuclear explosion test at high altitudes

作　　者：张彦[1] 王自发[2] 郑毅[1] 

机构地区：[1]防化研究院二所,北京102205 [2]中科院大气物理研究所竺可桢-南森研究中心,北京100029

出　　处：《安全与环境学报》2008年第3期115-121,共7页Journal of Safety and Environment

摘　　要：针对核试验期间的放射性烟云扩散,采用RAMS/CFORSⅡ模式,通过模拟两次高空核试验过程,研究烟云的空间分布、传输态势和地面沉降,模拟结果基本符合实际观测趋势。同时模拟得到了一些空爆核试验烟云在对流层和平流层中下层的传输规律。在空爆烟云的长距离传输中,主烟云受平流层西风急流影响明显,最快在爆后19h东移出境;在西风急流之上和对流层中,传输速度明显减小,烟云的扩散和沉降维持了3d以上。对流层中低层的天气系统对空爆烟云的近地面沉降有重要影响,较强的低压系统造成的地面沉降区域较小,接近均压场的天气形势造成的沉降区域较大,约比前者大1倍。较大的粒子主要在爆后前两天沉降在中国西部地区,东部以小粒子沉降为主,出现在第3d。小粒子的放射性很小,日沉降量在10-2～101Bq/m2之间,与天然放射性本底值相当。The aim of this paper is to uncover the regularities of the radioactive plume diffusion after the nuclear explosion test. For this purpose, we have adopted RAMS/CFORS Ⅱ model to simulate the concentration distribution of the test plume in the space, and their migrating and depositing process at two high altitudes through comparison between the simulated results and the observed data. At the same time, we have also discovered some other moving regularities of the plume in the troposphere and in the low-middle stratosphere. As is known, the plume movements Were dominated in the east-to-west direction in the stratosphere in long-distance, which used to move out of China＇s frontier in 19 hours later at the fastest speed after the explosion. However, above the stratosphere, or in the troposphere, the velocity of the plume floating tends to decrease obviously and their diffusion and deposition process were expected to last over 3 days. At this, it has to be noted that the synoptic system on low-middle troposphere propagation had made an important effect on the ground deposition of the test plumes. Furthermore, the stronger low-pressure system resulted in the smaller deposition area, the greater the deposit amounts the homogeneous-press system resulted in. Actually, the deposit amount can reach twice as much as the former. The past experience indicates that, in the west of China, the deposition amount has been dominated by coarse particles within 2 days after the explosion test, while, in the east of China, it was dominated by fine particles, which may last three days after the test with weak radioactive particles fine in shape. To be brief, the sum of deposition can be expected to change in 10^-2- 10^1 Bq/m^2 per day, rather close to the natural background radioactivities.

关 键 词：辐射防护及环境保护 RAMS/CFORSⅡ模式 核试验 沉降 扩散 高空 

分 类 号：X591[环境科学与工程—环境工程]