Numerical model for global atmospheric constituent change and development of high-speed execution method by parallel processing

本研究的目的首先是建立全球对流层成分变化的数值模式（大气成分的运输、扩散、化学和沉积的三维模式），并与大气全球环流模式（GCM）相结合，预测全球气候变化；其次是对数值模式进行验证。将其应用于东亚地区酸雨和黄沙远距离输送的区域空气质量问题。结合湍流扩散、气液相化学、干湿沉积等相关过程的子模型，采用球坐标系，构建了统一的全球大气成分变化数值模型。由于预测气溶胶对全球变暖的影响的不确定性比气体成分的不确定性要大得多，因此我们将重点放在气溶胶模型上，并使模型尽可能准确地预测气溶胶和温室气体的行为以及它们之间的相互作用。此外，为了大幅度减少计算时间，开发了并行处理程序和向量化程序，并采用了计算方案和计算机系统进行了实际应用。在各种气溶胶过程中，我们重点研究了三个过程，即气溶胶源汇、反应和辐射强迫。在源汇过程中，精确模拟了土壤粉尘的收缩过程，从而导致了东亚地区特有的空气质量。在气溶胶成核生长和气溶胶非均相反应子模型中，准确地处理了气体和气溶胶之间的热力学平衡，并广泛地模拟了达到平衡状态的速率和气溶胶的生长。在辐射强迫子模式中，特别注意了由于气溶胶对云的形成和降水的影响而产生的所谓间接辐射强迫。以东亚地区为例，模拟了东亚地区酸雨和黄沙的长距离输送，结果表明，黄沙对酸雨的中和作用和大气污染物排放增加引起的降水酸度的年变化得到了较好的预测。少

The purpose of this research project is firstly to develop a numerical model of global tropospheric constituent change (three-dimensional model of transport, diffusion, chemistry and deposition of atmospheric constituents) which should be coupled with an atmospheric global circulation model (GCM) to predict the global climate change, and secondly to validate the numerical model, applying it to the regional air quality problems on the long range transport of acid rain and yellow sand in East Asia.Combining all the sub-models for relevant processes such as turbulent diffusion, gas-and liquid-phase chemistry, dry and wet depositions, and adopting the spherical coordinate system, we constructed a unified numerical model of global atmospheric constituent change. Here, we focused our concentration on the aerosol modeling, since uncertainty in predicting aerosol effects on the global warning are much larger than that of gaseous constituents, and made the model as accurate as possible in predi … More cting the behaviors of both aerosol and greenhouse gases and interactions between them. In addition, in order to achieve a large reduction of the **cution time, a procedure for parallel processing as well as that for vectoralization was developed, and the resulted calculation scheme and computer system were adopted for practical use.Of the various aerosol processes, we focused on three processes, i. e., aerosol source-sink, reaction and radiative forcing. In the source-sink process, an accurate modeling was performed for the deflation of soil dust, which brought about the peculiar air quality in East Asia. In the aerosol nucleation and growth and aerosol heterogeneous reaction sub-model, thermodynamic equilibrium between gas and aerosol was treated accurately and the rate attaining at the equilibrium state and aerosol growth were modeled extensively. In the radiative forcing sub-model, a special attention was paid on the so-called indirect radiative forcing due to aerosol effects on the cloud formation and precipitation.As a case study, long range transport of acid rain and yellow sand in East Asia was simulated, and it was shown that the effects of the yellow sand on neutralizing the acid rain and annual change of the precipitation acidity due to the emission increase of air pollutants were predicted successfully. Less