Collaborative Research: From Fine-Scale Mixing to the Mesoscale--Assessing the Climatic Impact of Trade-Wind Cumulus with RICO Data and Modeling

将对海洋积云降雨（RICO）试验期间获得的数据集进行进一步分析。这些数据集包括在R/V苏厄德·约翰逊号上获得的扫描k波段云雷达数据、飞机现场微物理观测、陆基S-Pol极化气象雷达数据和卫星图像。这些分析将用于约束和改进热带浅层积云的数值模拟。其中一个重点是对信风积云种群的宏观物理和微观物理属性进行统计评估。统计数据将包括云顶高度、云深、水平尺寸和间距、降水和液态水含量。云生命周期将同时使用k波段和S-Pol雷达数据进行检查。从观测得到的统计关系将与从数值模式输出得到的统计关系进行比较。这将为模式提供观测约束，并允许改进模式中关于物理特性和浅层积云对热带低层大气影响的参数化。将对该地区在RICO实验期间和之后获得的卫星数据（包括卫星雷达观测）进行检查，以评估RICO期间观测到的联合反射率-高度分布的代表性，以及这些联合分布与区域地面风、可降水量和液态水路径的关系。研究的第二个重点将是验证通过这些云场的模型计算的三维辐射传输。最终目标是提高从热带浅积云中参数化降水的能力，并提供一个准确的参数化来解释它们的辐射效应，适合于在更大尺度气候模式中使用。这项工作的更广泛的影响是将RICO观测与数值模拟相结合，从而将RICO结果推广为对更广泛的大气科学界有用的经验。所要求的大部分资金将用于支持两名研究生的教育和培训。

Further analysis of datasets acquired during the Rain in Cumulus over Ocean (RICO) experiment will be performed. These datasets include scanning K-band cloud radar data acquired on the R/V Seward Johnson, aircraft in-situ microphysical observations, land-based S-Pol polarimetric weather radar data, and satellite imagery. These analyses will be used to constrain and improve the numerical modeling of shallow tropical cumulus clouds. One focus is a statistical assessment of both the macrophysical and microphysical attributes of populations of trade-wind cumuli. Statistics will include cloud top height, cloud depth, horizontal dimensions and spacing, precipitation, and liquid water content. Cloud lifecycles will be examined using simultaneous K-band and S-Pol radar data. The statistical relationships derived from observations will be compared to those derived from numerical model output. This will provide observational constraints on the model, and allow improvement of parameterizations in the model of the physical properties and effects of shallow cumulus clouds on the tropical lower atmosphere. Satellite data for the region, including satellite radar observations, obtained during and after the RICO experiment, will be examined to assess representativeness of joint reflectivity-height distributions observed during RICO, and the relationships of these joint distributions to regional surface winds, precipitable water vapor, and liquid water path. A second focus of the investigation will be validation of model-computed three-dimensional radiative transfer through these cloud fields. The ultimate goals are to improve capability to parameterize precipitation from shallow tropical cumulus, and to provide an accurate parameterization to account for their radiative effects suitable for use in larger-scale climate models. The broader impact of the work is the integration of RICO observations with numerical modeling, leading to generalization of RICO results into lessons useful to the much broader atmospheric science community. Much of the requested funding will be used to support the education and training of two graduate students.