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Estimation of the deposition rates of aerosol and sulfur compounds on forest and grassland with cosmic-ray produced radionuclides

用宇宙射线产生的放射性核素估算森林和草原上气溶胶和硫化合物的沉积率

基本信息

批准号：
13680605
负责人：
OSAKI Susumu
金额：
$ 2.18万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

Cosmic-ray produced radionuclides, e.g. ^7Be(the half life:53.3d), ^<32>P(14.3d), ^<33>P(25.3d), and ^<35>S(87.5d), have been produced mainly in upper atmosphere, and immediately bound to aerosol and sulfur compounds in atmosphere. Since their production rates can be estimated based on the strength of cosmic rays, they can trace the behavior of aerosol and sulfur compounds and elucidate the origins, the behavior and the resident times of their compounds. The decay products, ^<210>Pb(22y) and ^<210>Po(138d), of gaseous radioactive radon, ^<220>Rn and ^<220>Rn, are also used for the tracers.Sulfur compounds and above radionuclides have been determined from the samples of aerosol, rainwater, dry deposition and sulfur dioxide collected during each 10 days for one year. They were analyzed by three boxes model (the upper and the lower atmosphere, and the earth surface), and were estimated the transfer rates of aerosol and sulfur compounds upper atmosphere above Fukuoka.The dry deposition rates of aerosol onto various natural and artificial surfaces were measured using by a short half-life radionuclide of ^<212>Pb(10hr). The dry deposition rates of aerosol depend on the roughness (the height of grass or the depth of forest) and the nature of the surface.In order to elucidate the behavior of aerosol in the forest ecology, ^7Be, ^<210>Pb and ^<210>Po have been determined in the samples of stem flow, through fall, and rain water. Furthermore they have analyzed in the fifty parts of one whole tree of Japanese cedar. Their results suggest the behavior of aerosol in the forest ecology.

宇宙线产生的放射性核素，如^7Be(半衰期：53.3d)，^&lt；32&gt；P(14.3d)，^&lt；33&gt；P(25.3 d)，^&lt；35&gt；S(87.5d)，主要产生于高层大气，并与大气中的气溶胶和硫化物直接结合。由于它们的产生率可以根据宇宙射线的强度进行估计，因此它们可以追踪气溶胶和硫化物的行为，并阐明它们的化合物的来源、行为和停留时间。气态放射性氡的衰变产物~(210)Pb(22Y)和~(210)P_(138d)、~(220)Rn和~(220)Rn也用于示踪剂。硫化合物和以上放射性核素是从一年中每10天收集的气溶胶、雨水、干沉降物和二氧化硫样品中确定的。用三箱模型(上、下大气和地表)对其进行了分析，并估算了福冈上空大气中气溶胶和硫化物的传输速率。利用短半衰期放射性核素^&lt；212&gt；Pb(10hr)测量了气溶胶在各种自然和人造表面上的干沉积速率。气溶胶的干沉降率取决于粗糙度(草的高度或森林的深度)和地表的性质。为了阐明气溶胶在森林生态中的行为，测定了树干径流、穿透降雨和雨水中的^7Be、^&lt；210和^&lt；Pb和^&lt；此外，他们还对一整棵日本雪松的50个部分进行了分析。他们的研究结果表明了气溶胶在森林生态中的行为。