Collaborative Research: The Wasatch Hydrometeor Aggregation and Riming Experiment

模拟的风暴寿命和降水量对降水形成和冷凝物去除的参数化速率非常敏感。大量的先前研究表明，我们提供准确天气预报的能力的致命弱点在于模型如何表示批量微物理参数化（BMP），特别是当涉及到混合和冰相过程时。这里有两个核心问题：1）对于一个给定的气象情景，水凝物的习性和粒子直径（或面积）与粒子质量和下降速度有何关系？2)由于聚集和成霜过程，在风暴中水凝物的习性、大小、质量和下降速度之间的关系是如何演变的？下一代天气模型的BMP需要通过新的测量方法来了解，这些方法必须能够详细描述水凝物的形式，三维结构和下降速度，并以当地气象背景的详细信息为条件。 过去对这些问题的研究一直受到挑战，要么是数学上理想化冰晶形状的必要性，不精确的测量方法，或主观因素，由于需要直接的人类参与实地测量。智力价值：这个项目将消除大部分的猜测，在以前的观测工作与气象和微物理测量的前所未有的组合。在2011-2012年冬季，瓦萨奇水凝和日凌实验（WASHARX）的核心将是新开发的多角度雪花相机（MASC）。 这是一个潜在的变革性仪器，因为它将首次提供水凝物的全自动20微米分辨率多立体彩色摄影，沿着其下降速度的同步测量。 在湖城附近的瓦萨奇前线沿着的一个高海拔滑雪胜地的范围内，这些新仪器中的两个将安装在一个陡峭的、高度保护的侧面峡谷内。 两个MASC垂直间隔410 m。 该观测系统还将配备沿着整个峡谷760米深度的气象测量，以及云滴大小分布探测器和北卡罗来纳州州立大学的垂直指向1.2厘米微型降雨雷达。 这个项目的预期成果将是一个前所未有的数据集，将用于研究水凝物下降速度的关系和它们的垂直演变，由于聚合和riming过程中的风暴system.Broader影响：在我们的领域的科学进步经常依赖于广泛的访问新的工具。除了为未来天气和气候模型的集成提供新的BMP外，这项研究还将有助于支持我们打算为未来的科学领域计划提供的新仪器（和复制品的制造）的科学开发。事实上，已经为科学研究、环境安全应用和公众利益朝着这种仪器的商业化生产迈出了初步步伐。该项目还包括广泛的教育内容。在当地滑雪场获得的3D立体图像将通过与阿尔塔滑雪场合作开发的网站实时提供给教室和公众。 最后，我们将与当地K-12水平的教师合作，开发与当地气象学有关的雪花形式的模块。

Simulated storm lifetime and precipitation production is exquisitely sensitive to the parameterized rate of precipitation formation and condensate removal. Extensive prior research has shown that the achilles heel in our ability to provide accurate weather forecasts lies in how models represent bulk microphysics parameterizations (BMPs), particularly when it comes to mixed and ice phase processes. There are two core questions here:1) For a given meteorological scenario, how is hydrometeor habit and particle diameter (or area) related to particle mass and fallspeed?2) How do the relationships between hydrometeor habit, size, mass and fallspeed in a storm evolve due to aggregation and riming processes?The next generation of BMPs for weather models needs to be informed by new measurement methods that must be capable of detailed characterization of hydrometeor form, three-dimensional structure, and fallspeed, conditioned by detailed information about the local meteorological context. Past research into these problems has been challenged by either a necessity to mathematically idealize ice crystal shapes, imprecise measurement methods, or an element of subjectivity due to a need for direct human participation in field measurement.Intellectual merit:This project will remove much of the guesswork in prior observational efforts with an unprecedented combination of meteorological and microphysical measurements. For the winter of 2011-2012, the Wasatch Hydrometeor Aggregation and Riming Experiment (WASHARX) will have as its centerpiece the newly developed Multi-Angle Snowflake Camera (MASC). This is a potentially transformative instrument since it will provide, for the first time, fully-automated 20 ìm-resolution multiply-stereoscopic color photography of hydrometeors, along with concurrent measurement of their fallspeed. Within the bounds of a high-altitude ski resort along the Wasatch Front near Salt Lake City, two of these new instruments will be installed within a steep, highly protected side canyon. The two MASCs will be vertically separated by 410 m. This observing system will also be accompanied by meteorological measurements along the full canyon depth of 760 m, as well as a cloud droplet size distribution probe and the North Carolina State University's vertically-pointing 1.2 cm MicroRainRadar. The expected outcome of this project will be an unprecedented data set that will be used for studying hydrometeor fallspeed relationships and their vertical evolution due to aggregation and riming processes within a storm system.Broader impacts: Scientific progress in our field has regularly hinged on broad accessibility of new tools. In addition to providing new BMPs for future integration in weather and climate models, this study will help support scientific development of a new instrument (and manufacture of a replica) that we intend to make available for future scientific field programs. Indeed, initial steps have been made toward commercial production of this instrument for scientific research, environmental safety applications and public interest. The project also has a broad educational component. The 3D steroscopic images obtained at the local ski area will be made accessible in real-time to classrooms and the general public through a website developed in cooperation with Alta Ski Area. Finally, we will work with local K-12 level teachers to develop modules for relating snowflake form to local meteorology.