Novel Integrated Characterization of Microphysical Properties of Ice Particles Using In-Situ Field Measurements and Polarimetric Radar Observations

利用原位现场测量和偏振雷达观测对冰粒微物理特性进行新颖的综合表征

基本信息

批准号：
2029806
负责人：
Branislav Notaros
金额：
$ 64.7万
依托单位：
Colorado State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-10-01 至 2024-09-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2029806&HistoricalAwards=false
关键词：
Novel Integrated Characterization Microphysical Properties

项目摘要

East Coast Winter Storms (or Nor’easters) that develop off the eastern coast of the US from North Carolina northwards can be very devastating producing large amounts of snowfall, freezing rain, sleet and resultant flooding. The type of precipitation that falls at the surface is sensitive to subtle vertical changes of the environment conditions such as temperature and relative humidity. The National Weather Service’s recently modernized network of radars along with sophisticated numerical models are used to forecast the hazardous areas but they depend crucially on the physical properties of the various classes of precipitation such as size, shape, concentration, density, fall speed and composition which are highly variable in both space and time. This research is aimed at developing, implementing, and testing novel approaches to measurement, characterization, and analysis of the physical and scattering properties of ice particles in winter precipitation combining delicate optical, electronic, and mechanical instrumentation and state-of-the-art radars. These integrated field measurements are performed in collaboration with the Precipitation Research Facility at Wallops Island, Virginia, operated by the National Aeronautic and Space Administration, which falls along one of the climatological tracks of east coast winter storms. Accurate measurements of the physical and scattering properties of winter precipitation are crucial for advancement of numerical weather prediction models and in the correct interpretation of data from the recently modernized national network of weather radars. Hence this research can lead to improved winter precipitation forecasts (amount, location, and timing), which is of great importance to economy, safety, and everyday life, including all travel modes used by the public, and especially air travel and safety. Educational impacts include research training of graduate and undergraduate students, instrumentation development by students, and field experiences. The overarching goal of this research is to reduce uncertainties in the interpretation of radar signatures and improve the accuracy of the retrievals of liquid equivalent snow rate (SR) using an observationally-driven approach supported by advanced in-situ instrumentation and radars. More specifically, the first objective is to improve characterization of geometric parameters, particle size distribution (PSD), fall speeds, and “effective” density of ice particles, by optimizing the data from projected views in one plane, obtained by the Precipitation Instrument Package (PIP), two orthogonal planes, from the 2D-video disdrometer (2DVD), and multiple planes, provided by the 5-camera multi-angle snowflake camera (MASC) and 7-camera Snowflake Measurement and Analysis System (SMAS). The second objective is use of the combination of PIP, two 2DVD units and two 3D sonic anemometers (inside and outside a double-fence windshield) to characterize the effects of particle-turbulence in natural snowfall on the fall speed and “effective” density of particles. The third objective is related to closure based on achieved agreements of the “best” estimate of SR and forward modeled polarimetric variables from dual-polarization radar using PIP, 2DVD, MASC, and SMAS data with independent snow gauge and radar measurements, respectively. Some of the unique contributions of this project are: a student-built research instrument SMAS that offers 3D-shape reconstruction of particles using 6 cameras with the 7th camera simultaneously measuring fall speed; use of multiple instruments (MASC, SMAS, 2DVD, and PIP) to arrive at the “complete” PSD from 100 microns to 20 mm; experimental approach to study particle-turbulence effects on settling speeds, with data on vertical/horizontal movements, fall speeds and sizes, and habits (types) of particles provided by the PIP, 2DVD, and SMAS, respectively; and closure experiments with the agreement between predicted and measured SR and radar observables being evaluated based on the estimated measurement and parameterization errors.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

从北卡罗来纳州向北在美国东海岸发展的东海岸冬季风暴（或东北风暴）可能会造成巨大的破坏，产生大量降雪、冻雨、雨夹雪以及由此产生的洪水。对温度和相对湿度等环境条件的微妙垂直变化很敏感，国家气象局最近现代化的雷达网络以及复杂的数值模型用于预测危险区域，但它们主要取决于不同类别的物理特性。降水量如这项研究旨在开发、实施和测试冰的物理和散射特性的测量、表征和分析的新方法。这些综合现场测量是与美国国家航空航天局运营的弗吉尼亚州瓦洛普斯岛降水研究设施合作进行的。，它落在其中之一东海岸冬季风暴的气候轨迹的准确测量对于数值天气预报模型的进步以及对最近现代化的国家天气雷达网络数据的正确解释至关重要。改善冬季降水预报（数量、地点和时间），这对经济、安全和日常生活（包括公众使用的所有出行方式，特别是航空旅行和安全）具有重要意义。教育影响包括研究培训。的研究生和本科生，这项研究的总体目标是减少雷达特征解释的不确定性，并使用先进的观测驱动方法提高液体等效雪率（SR）反演的准确性。 - 现场仪器和雷达更具体地说，第一个目标是通过优化一个平面投影视图的数据来改进几何参数、颗粒尺寸分布（PSD）、下落速度和冰颗粒“有效”密度的表征。由降水仪器包（PIP）获得，两个正交平面，来自2D视频测距仪（2DVD），以及由5相机多角度雪花相机（MASC）和7相机雪花测量和分析提供的多个平面系统 (SMAS)。第二个目标是使用 PIP、两个 2DVD 装置和两个 3D 声波风速计（双栅栏内部和外部）的组合。挡风玻璃）来表征自然降雪中的颗粒湍流对颗粒下落速度和“有效”密度的影响。第三个目标与基于 SR 和正向建模极化变量的“最佳”估计达成的协议进行闭合相关。双偏振雷达，分别使用 PIP、2DVD、MASC 和 SMAS 数据以及独立的雪规和雷达测量。该项目的一些独特贡献包括：学生构建的研究仪器 SMAS，可提供 3D 形状重建。使用 6 个摄像机（其中第 7 个摄像机同时测量粒子下落速度）；使用多种仪器（MASC、SMAS、2DVD 和 PIP）获得从 100 微米到 20 毫米的“完整”PSD 实验方法来研究粒子湍流效应；关于沉降速度，分别由 PIP、2DVD 和 SMAS 提供有关垂直/水平运动、下落速度和尺寸以及颗粒习性（类型）的数据，以及使用根据估计的测量和参数化误差来评估预测和测量的 SR 和雷达可观测值之间的关系。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的协议影响审查标准进行评估，被认为值得支持。