Collaborative Research: SAVANT--Stable Atmospheric Variability ANd Transport

合作研究：SAVANT--稳定的大气变率和运输

• 批准号: 1733877
• 负责人: Junming Wang
• 金额: $ 49.37万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1733877&HistoricalAwards=false
• 关键词: Collaborative; Research; SAVANT; Stable; Atmospheric

Stable boundary layers (SBL) are still a relatively problematic component of atmospheric modeling, despite their frequent occurrence. While general agreement exists that Monin-Obukov similarity theory is not applicable in the SBL due to the non-homogeneous and non-stationary flow, no universal organizing theory for the SBL has been presented. This poses a problem when examining aerosol movement as a function of atmospheric dynamics. It is known that stable air stratification results in katabatic downslope winds, even in very shallow topographic airsheds. These downslope winds can converge with background flow, and it is hypothesized that this convergence provides a starting point for specific events, such as internal gravity waves (IGW). Even though the stable boundary layer is normally shallow, internal gravity waves can propagate at an angle from the horizontal plane, and modify local shear, thus generating periodic turbulent mixing in space. Few studies have examined this in low relief topographic areas. This project will conduct measurements to address these open issues. The major objective of the project is to quantify the effects of shallow cold air drainage on aerosol transport and dispersion. While the measurement campaign will result in a rich dataset, the research here will focus on answering the following questions:1.Under what mesoscale and microscale conditions (i.e. cloud cover, threshold wind speed, surface cover, stability regime, background flow, slope ratio and length, and gully volume) do converging flows exist?2.What is the spatial and temporal scale of turbulence forced oscillations and/or gravity waves generated by converging flows, and do these and do these oscillations/gravity waves follow the linear theory of IGW?3.How are aerosol dispersion and transport influenced by turbulence forced oscillations and/or gravity waves generated from a converging flow?The novel aspect of this work is the ability to identify turbulent events and features with aerosol lidars to add the missing spatial component to our current understanding.Intellectual Merit:The project will provide new knowledge on drainage and converging flows and their effects on aerosol transport in areas of low topographic variability. Especially of interest is how cloud cover, threshold wind speed, turbulence intermittency, topography, and stability regime affect the flows and aerosol transport. This project will fill the significant gaps in current model parameterizations of the flows and transport in SBL. It will provide new parameterizations and modifications to extend existing to the SBL theories. The project will also identify an empirical relationship between this resulting dispersion and the intensity of the convergence event.Broader Impacts:Scientific broader impacts will include a rich dataset as well as empirical relationships defining when and where convergence is likely to occur. These can be adapted in forecast models that are currently missing these relationships. The larger benefits to society are to a rich field data set to researchers interested in microscale meteorological impacts on agricultural crop security and those interested in predicting impacts of hazardous releases. In addition to this intrinsic benefit of scientific enquiry, the work will also seek to expand public knowledge in understanding the nature of scientific enquiry with a specific focus on instrumentation. The project will create a series of video modules for use in undergraduate classes and public education where traditional meteorology programs are not available.

稳定边界层（SBL）仍然是一个相对有问题的组成部分，大气模拟，尽管他们经常出现。虽然普遍同意存在的Monin-Obukov相似理论是不适用于SBL由于非均匀和非平稳流，没有普遍的组织理论的SBL已经提出。这在研究气溶胶运动作为大气动力学的函数时提出了一个问题。众所周知，稳定的空气层结会导致下坡风，即使在非常浅的地形空气区。这些下坡风可以与背景流汇合，并且假设这种汇合为特定事件提供了起点，例如内部重力波（IGW）。即使稳定边界层通常很浅，内部重力波也可以从水平面以一定角度传播，并修改局部剪切，从而在空间中产生周期性湍流混合。很少有研究在低起伏地形区对此进行了研究。该项目将进行测量，以解决这些未决问题。该项目的主要目标是量化浅层冷空气排放对气溶胶输送和扩散的影响。 虽然测量活动将产生丰富的数据集，这里的研究将集中在回答以下问题：1.在什么样的中尺度和微尺度条件下（即云量，阈值风速，表面覆盖，稳定性制度，背景流，坡度比和长度，沟体积），汇流存在？2.湍流强迫振荡和/或由会聚流产生的重力波的空间和时间尺度是什么，这些振荡/重力波是否遵循IGW的线性理论？3.湍流强迫振荡和/或会聚流产生的重力波如何影响气溶胶的扩散和输送？这项工作的新颖之处是能够识别湍流事件和气溶胶激光雷达的功能，以增加失踪的空间分量，我们目前的understanding.Intellectual优点：该项目将提供新的知识排水和合流及其对气溶胶输运的影响，在地形变化小的地区。特别感兴趣的是云量，阈值风速，湍流度，地形和稳定性制度如何影响流动和气溶胶输送。 该项目将填补SBL中流动和运输的当前模型参数化的重大空白。它将提供新的参数化和修改，以扩展现有的SBL理论。 更广泛的影响：科学上更广泛的影响将包括一个丰富的数据集，以及经验关系，界定何时何地可能发生收敛。这些可以在目前缺少这些关系的预测模型中进行调整。对社会的更大好处是为那些对农作物安全的微尺度气象影响感兴趣的研究人员和那些对预测危险排放影响感兴趣的研究人员提供了丰富的实地数据集。除了科学探究的这种内在好处之外，这项工作还将寻求扩大公众对科学探究性质的理解，特别关注仪器。该项目将创建一系列视频模块，用于传统气象学课程无法使用的本科课程和公共教育。