Development of an atmosphere-soil-vegetation model for investigation of radioactive materials transport in the terrestrial biosphere

陸域生態系での放射性物質の移行研究のための大気-土壌-植生モデルの開発

堅田 元喜; 永井 晴康  ; Zhang, L.*; Held, A.*; Sera, D.*; Klemm, O.*

Katata, Genki; Nagai, Haruyasu; Zhang, L.*; Held, A.*; Sera, D.*; Klemm, O.*

放射性物質等の環境負荷物質の移行解明を目的に、ガス・粒子状物質とその移行媒体となる水、そしてエネルギーの移動を厳密に計算する精緻な大気-土壌-植生1次元モデルを開発した。このモデルは、大気から植物へのガス状・粒子状物質の沈着を、葉の形状や葉面積の植物種による違いを含めて計算することができる。さまざまな環境条件でのモデルの性能評価試験によって、開発したモデルが乾燥・温帯気候下の裸地面や植生地での水や熱,ガス状・粒子状物質のフラックス,土壌中の温度や水分量,CO濃度等の観測結果を良好に再現することを示した。

In order to investigate the transport of radioactive materials we have developed a one-dimensional numerical model that predicts the transfer of water, heat, and gaseous and particulate matters in atmosphere-soil-vegetation continuous system. The model calculates dry, wet and fog deposition of gaseous and particulate matters onto vegetation, taken into account the dependency of plant species such as leaf shape and leaf surface area. As a result of performance tests of the model under various environmental conditions, the model predicted the observed temporal changes in heat, water and CO fluxes over vegetative and non-vegetative surface, and temperature, water content, and CO concentration in the soil under the temperate and arid climate. The model also reproduced observational data of mass fluxes of fog water and atmospheric gases such as ozone and , and number flux of nano-sized aerosols over the vegetation.