Development and Testing of a Simple Microphysical-ConvectiveRadiative Model of Marine Boundary-Layer Clouds

鉴于云凝结核（CCN）对气候的巨大潜在影响，它在确定云的全球分布及其光学特性方面的作用目前引起了人们的极大兴趣，但尚未得到很好的理解。通过模拟气溶胶、云和辐射之间的相互作用，以参数化的方式描述系统的关键组成部分，可以深入了解海洋边界层稳定状态的本质。有待开发、实施和测试的边界层云模型包括：(1)基于物理的CCN源、汇和输运参数化；(2)边界层云形成和消散的参数化，包括受CCN预报调节的毛毛雨形成的影响；(3)云边界层辐射传输的参数化，包括太阳和地面辐射；并考虑了云中颗粒的数量、密度和大小分布以及云中液态水的含量。将选择1992年大西洋层积云过渡实验（ASTEX）的一个案例研究来检验该模式。提出的研究将为今后将CCN物理纳入一般环流模型的工作奠定基础。

In view of their large potential climate impacts, the role of cloud condensation nuclei (CCN) in determining the global distribution of clouds and their optical properties is of great current interest, but is not yet well understood. Insight into the nature of the steady states attainable in the marine boundary layer will be obtained by simulating the interactions between aerosols, clouds, and radiation using a simple model that describes the key components of the system in a parameterized way. The boundary- layer cloud model to be developed, implemented, and tested includes: (1) A physically based parameterization of CCN sources, sinks, and transports; (2) A parameterization of boundary-layer cloud formation and dissipation, including the effects of drizzle formation as regulated by the predicted CCN; and (3) A parameterization of radiative transfer in the cloudy boundary layer, including both solar and terrestrial radiation, and taking into account the cloud particle number density and size distribution and the cloud liquid water content. A case study from the 1992 Atlantic Stratocumulus Transition Experiment (ASTEX) will be selected and used to test the model. The proposed study will provide a foundation for future work to incorporate CCN physics into general circulation models.