Using Aircraft Observations and Modelling to Improve Understanding of Mineral Dust Transport and Deposition Processes

利用飞机观测和建模来提高对矿物粉尘输送和沉积过程的了解

• 批准号: 2439550
• 金额: --
• 依托单位: University of Reading
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2439550
• 关键词: Using; Aircraft; Observations; Modelling; Improve

Every year thousands of tonnes of mineral dust particles are uplifted from arid regions by strong winds. While in the atmosphere, mineral dust is a hazard for health, transport and solar energy generation. Dust affects climate by interacting with clouds, radiation and other aerosols and altering the Earth's energy balance. In dusty regions such as North Africa and the tropical North Atlantic, dust has been shown to influence the West African Monsoon and Atlantic hurricane development. Dust forms an important link and climate feedback between components of the Earth system: emissions are driven by land-surface and atmospheric factors, whilst airborne it impacts on the atmosphere, and through deposition it provides a nutrient source to oceanic and terrestrial biogeochemical systems. Almost all dust processes are highly size dependent, and a realistic representation of the size distribution is critical for the simulation of the dust atmospheric lifecycle. However, models struggle to represent the evolution of dust size distributions. Processes such as triboelectric charging and non-sphericity have recently to be potentially important processes, yet are not included in dust models. This has knock-on effects on the ability of dust models to accurately represent the impact of dust on human health, infrastructure, weather and climate. Until recently, there has been a lack of observations of large dust particles (>10 microns). However, in the past ten years aircraft observations have utilized new technology to measure the full size range of dust, overcoming limitations of previous measurements. The new observational data include FENNEC near north African sources, AER-D in the west Atlantic and SALTRACE in both east and west Atlantic, providing constraints at various stages of the dust life cycle.The aim of the studentship is to use the new observations to investigate the effect of deposition and transport processes on the dust size distribution, thereby improving our understanding of dust physics and microphysics. The student will do this within the framework of the Met Office Unified Model (UM). Improved understanding of dust transport and deposition will be widely applicable, improving the representation of dust and its impacts in climate models. The studentship is supported by CASE sponsorship from the Met Office and linked to the NCAS-led ACSIS (North Atlantic Climate System Integrated Study) project, since dust transport is important in influencing Atlantic sea surface temperatures. Initially the observational data will be used to evaluate dust in a climate model simulation. Then the contribution of various processes to the evolution of dust size distribution across the Atlantic would be assessed by disabling each existing model process (e.g. sedimentation, convection) in turn, and by introducing novel processes such as the effects of non-sphericity and of triboelectric charging. Key processes would then be selected for more detailed investigation, using either the UM or a box model, with the aim of understanding the causes of size biases and identifying potential improvements. Finally, recommended developments would be tested on a global scale over climate timescales. Improvements will be directly applicable in the Met Office UK Earth System Model and Numerical Weather Prediction models.

每年有数千吨的矿物尘埃颗粒被强风从干旱地区吹走。在大气中，矿物粉尘对健康、运输和太阳能发电都是一种危害。沙尘通过与云、辐射和其他气溶胶相互作用并改变地球的能量平衡来影响气候。在北非和热带北大西洋等多尘地区，沙尘已被证明会影响西非季风和大西洋飓风的发展。粉尘是地球系统各组成部分之间的重要联系和气候反馈：排放受地表和大气因素驱动，而空气传播的粉尘影响大气，并通过沉积为海洋和陆地生物地球化学系统提供营养源。几乎所有的粉尘过程都是高度依赖于尺寸的，并且真实的尺寸分布的表示对于粉尘大气生命周期的模拟是至关重要的。然而，模型很难代表尘埃粒度分布的演变。诸如摩擦带电和非球形等过程最近成为潜在的重要过程，但未包括在尘埃模型中。这对沙尘模型准确反映沙尘对人类健康、基础设施、天气和气候影响的能力产生了连锁反应。直到最近，一直缺乏对大尘埃颗粒（> 10微米）的观测。然而，在过去的十年中，飞机观测已经利用新技术来测量灰尘的全尺寸范围，克服了以前测量的局限性。新的观测数据包括北非来源附近的FENNEC、西大西洋的AER-D和东大西洋和西大西洋的SALTRACE，为尘埃生命周期的各个阶段提供了制约因素，该奖学金的目的是利用新的观测来调查沉积和输送过程对尘埃大小分布的影响，从而提高我们对尘埃物理学和微观物理学的理解。学生将在气象局统一模型（UM）的框架内完成这项工作。更好地了解尘埃的输送和沉积将具有广泛的适用性，从而改善气候模型中尘埃及其影响的表现。该奖学金由英国气象局的CASE赞助支持，并与NCAS领导的ACSIS（北大西洋气候系统综合研究）项目相关联，因为尘埃输送对影响大西洋海面温度很重要。最初，观测数据将用于评估气候模型模拟中的尘埃。然后，通过依次禁用每个现有的模型过程（例如，沉降，对流），并通过引入新的过程，如非球形和摩擦带电的影响，各种过程的贡献跨越大西洋的尘埃粒度分布的演变进行评估。然后，将选择关键过程进行更详细的调查，使用UM或箱模型，目的是了解规模偏差的原因并确定潜在的改进。最后，建议的发展将在气候时间尺度上在全球范围内进行测试。改进将直接适用于英国气象局地球系统模型和数值天气预报模型。