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

本研究计画的目的首先是发展一个全球对流层成分变化的数值模式（大气成分的输运、扩散、化学和沉积的三维模式），该模式应与大气全球环流模式（GCM）耦合，以预测全球气候变化，其次是验证数值模式，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，将湍流扩散、气液相化学、干、湿沉降等相关过程的所有子模式结合起来，采用球坐标系，建立了全球大气成分变化的统一数值模式。由于气溶胶对全球警报影响的不确定性远大于气体成分的不确定性，因此，我们将重点放在气溶胶模型上，并使模型在预测全球警报时尽可能准确。 关于我们 气溶胶和温室气体的行为以及它们之间的相互作用。此外，为了大幅度缩短计算时间，还提出了一种并行处理和矢量化的方法，并将所得的计算方案和计算机系统用于实际应用。例如，气溶胶源-汇、反应和辐射强迫。在源-汇过程中，对引起东亚地区特殊空气质量的土壤降尘过程进行了精确的模拟。在气溶胶成核与生长和气溶胶非均相反应子模型中，精确地处理了气溶胶与气体之间的热力学平衡，广泛地模拟了气溶胶到达平衡态的速率和气溶胶的生长。在辐射强迫子模式中，特别注意气溶胶对云形成和降水的间接辐射强迫，并以东亚酸雨和黄沙的远距离输送为例进行了数值模拟。结果表明，黄沙对酸雨的中和作用和大气排放增加引起的降水酸度的年际变化具有一定的影响污染物预测成功。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