Collaborative Research: The Wasatch Hydrometeor Aggregation and Riming Experiment

模拟的风暴寿命和降水产生对降水形成和凝结水去除的参数速率非常敏感。先前广泛的研究表明，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整体微物理参数化(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)对于给定的气象情景，水流星习性和颗粒直径(或面积)如何与粒子质量和下降速度相关？2)风暴中水流星习性、大小、质量和下降速度之间的关系是如何由于聚集和结圈过程而演变的？下一代天气模式的BMP需要由新的测量方法提供信息，这些方法必须能够详细描述水流星的形状、三维结构和下降速度，并受当地气象背景的详细信息制约。过去对这些问题的研究受到了挑战，要么是需要对冰晶形状进行数学理想化，要么是测量方法不精确，要么是由于需要人类直接参与现场测量而带来的主观性因素。智力优势：这个项目将前所未有地结合气象和微物理测量，消除先前观测工作中的大部分猜测。在2011-2012年冬季，Wasatch水流星聚集和雾化实验(WASHARX)将以新开发的多角度雪花相机(MASC)为中心。这是一个潜在的变革性仪器，因为它将首次提供水流星的全自动20？m分辨率多立体彩色摄影，以及对其下降速度的同步测量。在盐湖城附近瓦萨奇前线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中。两个MASC将垂直相隔410米。该观测系统还将伴随着沿着整个峡谷深度760米的气象测量，以及一个云滴大小分布探测器和北卡罗来纳州立大学垂直指向的1.2厘米微雨雷达。该项目的预期结果将是一个史无前例的数据集，将用于研究由于风暴系统内的聚集和边缘过程而产生的水流星下降速度关系及其垂直演变。广泛的影响：我们领域的科学进步通常取决于新工具的广泛可获得性。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野外计划提供的新仪器的科学开发(和复制品的制造)。事实上，这种仪器的商业化生产已经迈出了初步的步骤，用于科学研究、环境安全应用和公众利益。该项目还包含广泛的教育内容。在当地滑雪区获得的3D立体图像将通过与阿尔塔滑雪区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级别的教师合作，开发将雪花形状与当地气象学联系起来的模块。

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.