Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061, USA.
National Center for Atmospheric Research, Boulder, CO 80305, USA.
Sensors (Basel). 2018 Dec 15;18(12):4448. doi: 10.3390/s18124448.
Concentrations of airborne chemical and biological agents from a hazardous release are not spread uniformly. Instead, there are regions of higher concentration, in part due to local atmospheric flow conditions which can attract agents. We equipped a ground station and two rotary-wing unmanned aircraft systems (UASs) with ultrasonic anemometers. Flights reported here were conducted 10 to 15 m above ground level (AGL) at the Leach Airfield in the San Luis Valley, Colorado as part of the Lower Atmospheric Process Studies at Elevation-a Remotely-Piloted Aircraft Team Experiment (LAPSE-RATE) campaign in 2018. The ultrasonic anemometers were used to collect simultaneous measurements of wind speed, wind direction, and temperature in a fixed triangle pattern; each sensor was located at one apex of a triangle with ∼100 to 200 m on each side, depending on the experiment. A WRF-LES model was used to determine the wind field across the sampling domain. Data from the ground-based sensors and the two UASs were used to detect attracting regions (also known as Lagrangian Coherent Structures, or LCSs), which have the potential to transport high concentrations of agents. This unique framework for detection of high concentration regions is based on estimates of the horizontal wind gradient tensor. To our knowledge, our work represents the first direct measurement of an LCS indicator in the atmosphere using a team of sensors. Our ultimate goal is to use environmental data from swarms of sensors to drive transport models of hazardous agents that can lead to real-time proper decisions regarding rapid emergency responses. The integration of real-time data from unmanned assets, advanced mathematical techniques for transport analysis, and predictive models can help assist in emergency response decisions in the future.
空气中化学和生物制剂的浓度从危险释放物中释放出来并不会均匀分布。相反，存在着浓度较高的区域，部分原因是局部大气流动条件可以吸引制剂。我们为一个地面站和两个旋翼无人机系统（UAS）配备了超声风速仪。这里报告的飞行是在科罗拉多州圣路易斯谷的 Leach 机场进行的，飞行高度为离地 10 至 15 米（AGL），作为 2018 年低空大气过程研究在海拔-遥控飞机团队实验（LAPSE-RATE）活动的一部分。超声风速仪用于以固定三角形模式收集风速、风向和温度的同步测量；每个传感器位于三角形的一个顶点，每条边约 100 至 200 米，具体取决于实验。使用 WRF-LES 模型确定采样域中的风场。地面传感器和两个 UAS 的数据用于检测吸引区域（也称为拉格朗日相干结构，或 LCS），这些区域有潜力输送高浓度的制剂。这种检测高浓度区域的独特框架基于水平风速梯度张量的估计。据我们所知，我们的工作代表了首次使用传感器团队直接测量大气中的 LCS 指标。我们的最终目标是使用传感器群的环境数据来驱动危险制剂的传输模型，这可以导致针对快速应急响应的实时正确决策。无人资产的实时数据、运输分析的先进数学技术和预测模型的集成可以帮助在未来协助应急响应决策。
