Geophysical mechanisms governing particle transport by wind

风控制粒子传输的地球物理机制

• 批准号: RGPIN-2019-03969
• 负责人: McKennaNeuman, Cheryl
• 金额: $ 3.13万
• 依托单位: Trent University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=764542
• 关键词: Geophysical; mechanisms; governing; particle; transport

Wind is ubiquitous at Earth's surface, as well as on other planetary bodies such as Mars, Venus and Titan. Where any source of loose particles exists, the fluid drag of the wind may entrain and carry some fraction of these particles over distances varying from just a few millimeters to several meters and ultimately in the case of dust in long-term suspension, over thousands of kilometers. As such, the transport of these particles may affect air quality, visibility, the absorption and transmission of solar radiation, climate, soil fertility, and through deposition, surface topography (e.g. dunes).       While technically any form of particle can be transported in an airflow, my long-term research program funded by the NSERC Discovery Grant program is primarily focused upon natural sedimentary particles. My principal methodological approach is founded on the use of a boundary-layer wind tunnel to study the geophysical processes that govern particulate matter (PM) transport in air flows. Less than a half dozen such facilities in the world are typically engaged in work of this type at any given point in time. The Trent Environmental Wind Tunnel (TEWT) is distinguished as supporting one of the longest standing and most continuous research programs investigating (aeolian) sedimentary processes. It also is the only one of its type to be located in an environmental chamber with full climate control down to subfreezing temperatures. Laser based technologies available within TEWT include Particle Tracking Velocimetry (PTV) for investigating particle dynamics; Laser Doppler Anemometry (LDA) for sampling the properties of the airflow structure and particle kinetic; and LiDAR for mapping the surface morphometry.       The proposed work will use the leading-edge technologies available within TEWT to investigate: i) the dynamics of discrete particle impacts and ejections during their transport across wet and frozen sedimentary bed surfaces, ii) particle impact, splash, creep and segregation during the inception, growth and migration of ballistic ripples as found on a range of planetary surfaces, iii) the role of turbulence generation in dust emission and dispersion, and iv) the role of aggregate disintegration in dust generation. Each of these studies will increase understanding of the geophysical system, provide direct measurements for the parameterization and calibration of various sediment transport and dust emission models, and may ultimately lead to improvements in practices that aim to mitigate wind erosion and improve air quality. Training will be provided for six graduate students (2 PhD and 4 MSc) and five senior undergraduate thesis students, who will undertake this work and contribute to its dissemination through conference presentations and publication.

风在地球表面以及其他行星体上无处不在，例如火星，金星和泰坦。如果存在任何松散的颗粒来源，风的流体阻力可能会进入，并将这些颗粒的一小部分带到距离上，从仅几毫米到几米，最终在长期悬浮液中，数千公里，最终是尘埃落定的。因此，这些颗粒的运输可能会影响空气质量，可见性，太阳辐射，气候，土壤肥力的抽象和传播以及通过沉积，表面形貌（例如沙丘）。尽管从技术上讲，任何形式的粒子都可以在气流中运输，但由NSERC Discovery Grant计划资助的我的长期研究计划主要集中在天然沉积物颗粒上。我的主要方法论方法是建立在使用边界风隧道来研究控制空气流中特定物质（PM）的地球物理过程的基础上的。在任何给定时间点，世界上不到六个这样的设施通常都从事此类工作。特伦特环境风洞（TEWT）被区分为支持最长，最连续的研究计划调查（Aeolian）沉积过程之一。它也是其唯一位于具有完全气候控制的环境室中的一种类型，以降至亚冻结温度。 TEWT中可用的基于激光的技术包括用于研究粒子动力学的粒子跟踪速度测定（PTV）；激光多普勒驱动器（LDA），用于对气流结构和粒子动力学的性质进行采样；和lidar用于映射表面形态测定法。 The proposed work will use the leading-edge technologies available within TEWT to investigate: i) the dynamics of discrete particle impacts and ejections during their transport across wet and frozen sedimentary bed surfaces, ii) particle impact, splash, creep and segregation during the inception, growth and migration of ballistic ripples as found on a range of planetary surfaces, iii) the role of turbulence generation in dust emission and dispersion, and iv）总体分解在灰尘产生中的作用。这些研究中的每一个都将增加对地球物理系统的理解，为各种沉积物传输和灰尘发射模型的参数化和校准提供直接测量，并最终可能会改善旨在减轻风侵蚀并改善空气质量的实践。将为六名研究生（2位博士学位和4个MSC）和五位高级本科论文专业的学生提供培训，他们将从事这项工作，并通过会议演讲和出版物为其传播做出贡献。