地球系统模式若干基本问题与参数化方法研究

A series of researches will be started focusing on some key problems widely existed in most of the current Earth System Models. Our researches will be carried out on the platform of CAS-ESM (V1.0） (Earth System Dynamics Model in Chinese Academy of Sciences, Version 1.0). Several fundamental mathematical/physical theories, numerical algorithms and elaborate physical parameterization schemes will be applied to improve the CAS-ESM in the following aspects:.1..Strict mathematical proofs and physical verifications will be applied to improve the mathematical rationality, well-posedness and the physical consistency of the current version of the CAS-ESM, especially to proof the existence of the weak solutions to the initial boundary value problems for the coupled Atmospheric- Oceanic Model;.2..To develop a new scheme to solving the CAS-ESM over the Polar Regions keeping the physical characteristics of the rotational earth fluids with high calculating efficiency;.3..To investigate physical and dynamical processes and the well-posed boundary conditions over the ocean-atmosphere surfaces: to provide the fluxes parameterization formulas due to the non-classical turbulence and the effects of sea sprays in air-sea boundary layer. These will improve the OGCM and AACM;.4..To investigate the effects of the non-uniformity of land surface in the sub-grid scales (e.g. the fine structure of the urban canyons) and the vegetation establishment/litter processes; to develop and improve the related parameterization schemes in CoLM and DGVM/CAS-ESM; .5..To improve the description of the processes of uniform\overlapped clouds schemes and optimize the combination schemes in the Cloud-Aerosol-Radiation models (CAR) to deduce the uncertainty in climate simulation..The results will be very important in improving the simulation capacity of the CAS-ESM and also make a solid foundation for developing the next generation of CAS-ESM.

针对当今地球系统模式普遍存在的一些关键问题, 以中国科学院地球系统模式CAS-ESM1.0为基础和平台, 拟从若干基本理论、数值方法及精细物理过程参数化方案入手开展如下研究：.1.通过严格的物理数学分析改进ESM的物理内部协调性和数学合理性，证明海气耦合模式动力框架弱解的存在性等；.2.发展保持旋转流体物理特性且具有较高并行计算效率的极区计算方案；.3.研究海气耦合边界层的物理和动力过程及边界条件适定性问题，给出海气边界层非经典湍流及海洋飞沫导致的通量参数化方案；改进海洋环流模式和气溶胶与大气化学模式；.4.研究陆面次网格非均匀性（如精细化城市冠层）和植株萌衍凋落模型；发展和改进相应的陆表层模式和植被动力学模式；研究不均匀和重迭云表达方法和优化云-气溶胶-辐射方案，减小云导致的气候模拟不确定性。.通过以上研究改进CAS-ESM1.0并为发展下一代模式打好基础。

项目基于中国科学院地球系统模式CAS-ESM1.0，围绕地球系统模式中的关键核心问题，完成了如下工作：1.证明了海气耦合模式动力学框架整体弱解的存在性，以及考虑水汽相变过程的大气环流模式IAP-AGCM动力学框架整体强解的存在唯一性等；2.设计了极区与其外区匹配的计算方法和格式，并进行了检验；3.分析了海—气耦合边界层特征及其对海洋飞沫垂直传输的影响，研发了近海大气边界层海洋飞沫的测量技术和飞沫通量参数化方案，提出正确的海洋环流模式中的盐度上边界条件和气溶胶与大气化学模式中的海盐气溶胶排放方案；4.发展了一套基于城市复杂下垫面布局特征的城市街谷冠层结构模型的参数化方案；5.改进了全球植被动力学模式中的植株萌衍方案，对改进的模型进行数值模拟和评估，并应用该模型研究了全球自然植被分布和碳通量对全球变暖的响应；6.实现了云-气溶胶-辐射系统与大气环流模式IAP AGCM的耦合，探索了云-气溶胶-辐射方案的最优组合。.上述基础数学物理问题和关键过程的参数化方案是中科院地球系统模式CAS-ESM2.0定版的重要模块，并使其分系统更全面、理论更严谨。目前，CAS-ESM2.0已参加第六次国际模式比较计划CMIP6，其模拟结果也证明了该模式是世界上模拟能力最好的地球系统模式之一。