Boundary Layer Clouds and Climate

将使用观测和理论模型来研究海洋平流层积云的产生、维持和消散所涉及的物理过程。这些过程将在当前版本的NCAR社区气候模式(CCM)中表示(或参数化)，以提供对低层云量以及固体和部分云条件下相关的地面水汽和能量通量的改进模拟。将利用1987年6月29日至7月19日在第一次国际卫星云气候学区域实验(FIRE)现场阶段从加利福尼亚州南部海岸外的飞机和卫星观测收集的数据，以及通过该参数化的区域应用，来测试和开发将用于发展这种参数化的热力学和动力学模式。这些研究将利用从NCAR Electra和UK C-130获得的平均、湍流、云微物理和辐射测量，来自卫星的云观测，以及来自ECMWF的天气尺度分析。拟议过程研究的重点将是云顶的夹带和混合、海洋层积中的对流环流，以及控制云结构时空变化的因素。理论工作将涉及使用辐射强迫的18系数湿光谱模型，该模型包括水平变化的基于云的高度和云顶高度以及云上逆温层。该模式的理论结果将与火灾测量得到的结构进行比较，并将为嵌入CCM的边界层模式中参数化的环流速度提供动力学基础。这项研究之所以重要，是因为它打算增加对云层如何影响气候的理解。

The physical processes involved in the generation, maintenance, and dissipation of marine stratocumulus will be studies using observations and theoretical models. These processes will be represented (or parameterized) in the current version of the NCAR community Climate Model (CCM) to provide improved simulations of low-level cloudiness and the associated surface fluxes of moisture and energy for both solid and partially cloud conditions. The thermodynamic and dynamic models that will be used to develop this parameterization will be tested and developed by using data collected from aircraft and satellite observations made off the coast of southern California from June 29 to July 19, 1987 during the field phase of the First International Satellite Cloud Climatology Regional Experiment (FIRE) and by a regional application of the parameterization. These studies will make use of mean, turbulence,cloud microphysics, and radiation measurements obtained from NCAR Electra and the UK C-130, cloud observations from satellites, and synoptic-scale analyses from the ECMWF. The focus of the proposed process studies will be on entrainment and mixing at cloud top,convective circulations in marine stratocumulus, and factors that control the spatial and temporal variations in the cloud structure. The theoretical work will involve the use of a radiatively-forced 18-coefficient moist spectral model that include horizontally varying cloud- based and cloud-top heights an dan above-cloud inversion layer. The theoretical results from this model will be compared with the structure obtained from the FIRE measurements and will provide the dynamical basis for the circulation velocities that are parameterized in the boundary layer model that will be embedded in the CCM. This research is important because it intends to increase understanding of how clouds influence climate.