Permalink : http://hdl.handle.net/2115/55063

The influence of aerosol-cloud interactions on the behavior of marine stratocumulus is investigated through numerical simulations of an idealized meteorological system in which aerosols are formed continuously. The super-droplet method is used for the simulation of cloud microphysical processes, with which the time evolution of aerosol/cloud/precipitation particles is calculated in a unified manner. For the simulation of atmospheric fluid dynamical processes, the quasi-compressible approximation and the sound mode splitting method are applied. The system gradually evolves to reach its final steady state in a few days, which is irrelevant to the initial number density of aerosols. A transition of the final steady state from cumuli to strati occurs when the aerosol formation rate is increased. Because the chemical reaction in the gas phase and the liquid phase is not incorporated, the model is not detailed enough to describe aerosol-cloud interactions. Further, the numerical simulations are performed in two dimensions. For these reasons, the results obtained are still all preliminary
洋上の浅い層積雲にエアロゾルと雲の相互作用が及ぼす影響を,持続的にエアロゾルが形成される理想化された気象システムの数値計算により調べる.雲微物理過程の数値計算には超水滴法を使い,エアロゾル・雲粒・降水粒子のふるまいを統一的に計算する.大気流体場は準圧縮近似の下で音波モードとそれ以外を分割して数値計算する.初期のエアロゾル数密度によらず系は数日後にある定常状態に落ち着くこと,その定常状態はエアロゾル生成率が大きくなるに伴い積雲から層雲に転移することを見る.今回のモデルでは,気相や液相での化学反応までは考慮していないためエアロゾルと雲の相互作用が完全に表現できてはおらず,また数値計算も鉛直２次元で行うため,この結果はあくまで予備的なものである.