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

将对在海洋积云降雨(RICO)实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 Seward Johnson上获取的扫描K波段云雷达数据、飞机现场微物理观测、陆基S-波尔极化天气雷达数据和卫星图像。这些分析将被用来约束和改进热带浅层积云的数值模拟。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、云深度、水平尺寸和间距、降水量和液态水含量。云的生命周期将使用同时的K波段和S-波尔雷达数据进行研究。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。这将对模式提供观测约束，并允许改进模式的物理性质和浅积云对热带低层大气的影响的参数化。将对在RICO实验期间和之后获得的该区域的卫星数据，包括卫星雷达观测数据进行检查，以评估在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、可降水水汽和液态水路径的关系。调查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。其最终目标是提高对热带浅积云降水进行参数化的能力，并提供一种准确的参数化，以说明它们的辐射效应，适合用于更大尺度的气候模式。这项工作的更广泛影响是将RICO观测与数值模拟相结合，导致将RICO结果推广为对更广泛的大气科学界有用的经验教训。申请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.