Collaborative Research: Cloud System Evolution in the Trades

合作研究：行业云系统演进

• 批准号: 1445813
• 负责人: Robert Wood
• 金额: $ 48.22万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1445813&HistoricalAwards=false
• 关键词: Collaborative; Research; Cloud; System; Evolution

This study aims to understand the evolution of the boundary layer cloud, aerosol and thermodynamic structures along trajectories within the north-Pacific trade-winds using observations from the NSF/NCAR Gulfstream V (HIAPER). This effort includes characterization of the cloud, precipitation and aerosol fields in the stratocumulus (Sc) and the fair-weather cumulus (Cu) regimes within the subtropical easterlies over the northern Pacific and the use of Large Eddy Simulation (LES) models to simulate the cloud evolution along the trajectories sampled. Intellectual merit: These characterizations along trajectories will be designed to aid in our understanding and simulation of the transition between the two convective regimes - a critical factor in the climate system. LES models have become a robust tool for Lagrangian simulations of subtropical cloudiness transitions, but there are few good datasets for comprehensively testing these simulations. In particular, adequate observations of the coupled evolution of aerosol, cloud droplet number concentration and precipitation during such transitions are lacked. Thus, the observing strategy will be to sample aerosol, cloud, precipitation, and boundary layer properties upwind from the transition zone over the North Pacific and to resample these areas two and four days later. This Lagrangian approach is designed to minimize uncertainties in the large-scale forcing due to horizontal advection in the lower troposphere as air masses move from colder to warmer sea surface temperatures and thus facilitate model simulations and isolate critical physical processes. Two key elements of the observing system will be a newly developed HIAPER Cloud Radar (HCR) and the HIAPER High Spectral Resolution Lidar (HSRL). The HCR will be used to provide cloud and precipitation characteristics. The HSRL will provide cloud boundaries and aerosol characteristics when viewing non-cloudy volumes. A full suite of probes on the aircraft will be used for in situ measurements of aerosol, cloud, precipitation, and turbulence properties. Two modes of operations will be made on flights between the west coast of California and Hawaii. One will include remote sensing (mapping) of the clouds and boundary layer from flight levels above the boundary layer made upstream and downstream from the Sc to Cu transition zone. The other will involve detailed profiling in the subcloud and cloud layer in two or three selected areas upstream and downstream from the transition zone to make detailed in situ measurements of aerosols, clouds, precipitation, and turbulence. On the surveying legs dropsondes will be used to obtain the thermodynamic and wind structure in and above the boundary layer. Several flight sequences are planned for the June-July 2015 timeframe. The observations made on these flights will be used to evaluate the moisture, dry static energy and mass budgets by estimating the changes in these parameters between the upstream Sc region sampled on one flight and the downstream Cu region sampled on the subsequent flights. The synthesis of the observations will provide an observational framework for LES studies that will provide a better understating of cloud system evolution in the trades. Broader impacts: The project will develop observing and analysis techniques and strategies that will facilitate the development of future missions aimed at studying boundary layer clouds in remote areas that are not easily reached by other observing platforms. The data sets developed will be useful for evaluating satellite retrieval techniques and for evaluating models and model parameterizations applied to a wide range of scales--microphysical, mesoscale, regional, and global. The educational components of this project will include the training of graduate and undergraduate students on the technical aspects of the data collection processes, flight operations, and the subsequent analysis of data to address key science questions. Further, integration of observations from the project into teaching and learning modules that can be used at both the undergraduate and the graduate level will be developed.

本研究旨在利用 NSF/NCAR Gulfstream V (HIAPER) 的观测结果了解北太平洋信风内边界层云、气溶胶和热力学结构沿轨迹的演变。这项工作包括对北太平洋副热带东风区层积云 (Sc) 和晴天积云 (Cu) 区域中的云、降水和气溶胶场进行表征，并使用大涡模拟 (LES) 模型来模拟云沿着采样轨迹演化。智力价值：这些沿轨迹的特征将有助于我们理解和模拟两种对流状态之间的转变——这是气候系统中的一个关键因素。 LES 模型已成为副热带云量转变拉格朗日模拟的强大工具，但用于全面测试这些模拟的良好数据集很少。特别是，缺乏对这种转变期间气溶胶、云滴数浓度和降水耦合演化的充分观测。因此，观测策略将是从北太平洋过渡区逆风对气溶胶、云、降水和边界层特性进行采样，并在两天和四天后对这些区域重新采样。这种拉格朗日方法旨在最大限度地减少由于气团从较冷的海面温度移动到较温暖的海面温度时对流层下部的水平平流造成的大规模强迫的不确定性，从而促进模型模拟并隔离关键的物理过程。该观测系统的两个关键要素是新开发的 HIAPER 云雷达（HCR）和 HIAPER 高光谱分辨率激光雷达（HSRL）。 HCR 将用于提供云和降水特征。在查看非多云体积时，HSRL 将提供云边界和气溶胶特征。飞机上的全套探头将用于气溶胶、云、降水和湍流特性的现场测量。加利福尼亚州西海岸和夏威夷之间的航班将采用两种运营模式。其中一项将包括从钪到铜过渡区上游和下游的边界层上方的飞行高度对云层和边界层进行遥感（测绘）。另一项将涉及过渡区上游和下游两个或三个选定区域的亚云和云层的详细剖面分析，以对气溶胶、云、降水和湍流进行详细的现场测量。在测量腿上，将使用下投式探空仪来获取边界层内外的热力学和风结构。计划在 2015 年 6 月至 7 月期间进行多个飞行序列。在这些飞行中进行的观测将用于评估水分、干燥静态能量和质量预算，方法是估计一次飞行中采样的上游 Sc 区域和后续飞行中采样的下游 Cu 区域之间这些参数的变化。观测结果的综合将为 LES 研究提供一个观测框架，从而更好地了解行业中云系统的演变。更广泛的影响：该项目将开发观测和分析技术和战略，以促进未来任务的发展，旨在研究其他观测平台不易到达的偏远地区的边界层云。开发的数据集将有助于评估卫星检索技术以及评估应用于广泛尺度（微物理、中尺度、区域和全球）的模型和模型参数化。该项目的教育部分将包括对研究生和本科生进行数据收集过程、飞行操作以及随后的数据分析以解决关键科学问题的技术方面的培训。此外，还将开发将该项目的观察结果整合到可用于本科生和研究生水平的教学和学习模块中。