EAGER: Observations of Falling and Lofted Snow in Windy Environments

雪花的大小和形状是降雪数值模拟和气象雷达实时探测的重要考虑因素。影响雪花结构、密度和数量集中的一个鲜为人知的因素是风。传统的方法很难在大风条件下对飘落或飘动的雪进行地面或近地观测。较新的仪器，如用于机载研究的仪器，要么价格昂贵，要么有其他限制。在这个项目中，研究小组将部署一种新的气球载仪器，从降水层的表面到顶部测量雪花。还将部署一套额外的仪器，以补充从小学到研究生的学生参加的实地运动中的这些测量。该奖项的第一个影响将是测试一种新的、廉价的测量雪的技术。这项工作更大的潜在影响将是改善模型对雪的表示，以改善天气预报。该奖项还包括一个重要的教育和公众宣传组成部分，以提高公众对科学的理解和培训下一代研究人员。该奖项的主要目标是提高对有风条件下雪的微观物理方面的观测知识。由于图像模糊、仪器周围流动以及缺乏垂直剖面的能力，使用传统技术很难对飘落或飘雪进行地面或近地观测。此外，用于雪花分类的先进仪器要么价格昂贵，要么无法用于小型部署。在这个项目中，研究小组将使用一系列仪器，包括由国家强风暴实验室开发的粒子大小、图像和速度（PASIV）探测器。PASIV可以附着在气球上，用于颗粒计数和数量浓度估计的垂直剖面。在地面上，研究小组将使用相机闪光灯设置，相机的焦平面距离任何潜在的流动中断1-2米。额外的仪器将包括云粒子成像仪和测差仪。该场址在WSR-88D雷达和UND c波段雷达的视野之内。总体而言，野外实验的设计旨在回答两个主要问题：1)在落雪和升雪事件中，冰相水成物的微物理性质在100 - 10公里的水平和垂直尺度上是如何变化的；2)不同的仪器设计在多风环境中的作用如何？预期的更广泛影响包括与实地运动有关的重要外联和教育计划。该项目将资助一名研究生，约20名本科生和研究生将参与实地活动的规划、教学、预测和数据收集。K-12的外展将包括学生在冬季活动期间进行的降雪和能见度测量，冬季天气课程的开发，以及通过与现有EPSCoR奖合作向部落团体教授该单元。还将通过媒体和参观进行外联。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Snowflake size and shape are important considerations for numerical modeling of snowfall and real-time detection by weather radars. One of the lesser-understood factors that influences snowflake structures, densities and number concentrations is wind. Traditional methods to make ground or near-ground observations of falling or lofted snow in high wind conditions are difficult. Newer instruments, such as those used for airborne research, are expensive or have other limitations. In this project, the research team will deploy a new balloon-borne instrument to make measurements of snowflakes from the surface to the top of the precipitation layer. A set of additional instrumentation will also be deployed to complement those measurements in a field campaign that will involve students from elementary school to graduate level. The first order impact of the award will be to test a new, inexpensive technology for making measurements of snow. The larger potential impact of the work would be to improve model representation of snow for improved weather forecasts. The award also includes a significant education and public outreach component, leading to improved public understanding of science and training of the next generation of researchers.The main goal of this award is to improve observational knowledge of the microphysical aspects of snow during windy conditions. It is difficult to make ground or near-ground observations of falling or lofted snow using traditional techniques due to blurring of the images, flow around instruments, and the lack of ability to vertically profile. In addition, advanced instruments for snowflake classification are either expensive or unavailable for small deployments. In this project, the research team will make use of a combination of instruments, featuring the Particle Size, Image, and Velocity (PASIV) probes developed at the National Severe Storms Lab. The PASIV can be attached to a balloon for a vertical profile of particle counts and number concentration estimation. At the ground level, the research team will make use of a camera-strobe light setup where the focal plane of the camera is 1-2m from any potential flow disruption. Additional instruments will include a cloud particle imager and disdrometer. The field site is within view of the operational WSR-88D radar and the UND C-band radar. Overall, the design of the field experiment is set to answer two main questions: 1) How do microphysical properties of ice-phase hydrometeors vary over horizontal and vertical scales of 100m to 10km within falling and lofted snow events, and 2) How well do varying instrument designs function in windy environments? The intended broader impacts include a significant outreach and education plan associated with the field campaign. A graduate student will be funded by the project and approximately 20 undergraduate and graduate students will participate in the planning, teaching, forecasting, and collection of data for the field campaign. K-12 outreach will include snowfall and visibility measurements made by students during winter events, the development of a winter-weather curricula, and teaching of the unit to tribal groups through partnership with an existing EPSCoR award. Outreach via media and tours will also be conducted.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.