CEDAR: Quantitative Measurements of Lightning-Mesosphere Interactions from Remote Electromagnetic Fields

CEDAR：远程电磁场闪电-中间层相互作用的定量测量

• 批准号: 0436585
• 负责人: Steven Cummer
• 金额: $ 19.24万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0436585&HistoricalAwards=false
• 关键词: CEDAR; Quantitative; Measurements; Lightning; Mesosphere

The investigators will analyze existing electromagnetic field and video data associated with transient luminous events (TLEs) in the middle atmosphere to quantitatively measure parameters related to processes that are directly related to existing models. Sprites and other mesospheric TLEs are a visual manifestation of the direct coupling between the troposphere and upper atmosphere. The study of these phenomena has reached the point where observations and qualitative understanding are probably sufficient to begin realistically quantifying their micro- and macroscale effects and their significance in the larger mesosphere-lower thermosphere-ionosphere (MLTI) system. Quantitative understanding of TLE internal processes is a necessary first step towards understanding the effects of TLE-related processes on the MLTI system; without understanding in detail what happens inside them, it is nearly impossible to extrapolate their large-scale effects. And there are aspects of TLE phenomena that are not explained by present models, suggesting that understanding of TLE internal processes may not be sufficient to evaluate these effects. The study will focus on the following four science questions: Do influences beyond the lightning-driven electromagnetic fields, such as gravity waves and meteoritic dust, play a role in TLE-generating processes? What electromagnetic field strengths are required to initiate TLE-generating mesospheric processes? Is there an asymmetry in TLE production between positive and negative polarity cloud-to-ground lightning discharges? Is there an identifiable difference in optical emissions or driving lightning parameters between sprites that do and do not contain sprite current? Answering these questions will substantially improve quantitative understanding of lightning-ionosphere coupling processes and, consequently, the ability to predict their larger scale effects. The study will make use of past experimental measurements as well as observations to be made with existing instrumentation. Sprites and TLEs are not only visually spectacular. They are also manifestations of the complex electrical processes that exist in thunderstorms and link the lower atmosphere to the upper atmosphere.

研究人员将分析现有的电磁场和与中层大气中的瞬态发光事件（TLE）相关的视频数据，以定量测量与现有模型直接相关的过程相关的参数。SPRITE和其他中层TLE是对流层与高层大气直接耦合的直观表现。对这些现象的研究已经达到了这样的程度，即观测和定性理解可能足以开始现实地量化其微观和宏观尺度的影响及其在较大的中间层-低热层-电离层系统中的意义。定量了解TLE内部过程是了解TLE相关过程对MLTI系统影响的必要的第一步;如果不详细了解它们内部发生的事情，几乎不可能推断它们的大规模影响。TLE现象的某些方面无法用现有的模型解释，这表明对TLE内部过程的理解可能不足以评估这些影响。这项研究将集中在以下四个科学问题：除了闪电驱动的电磁场之外，重力波和陨石尘埃等影响是否在TLE生成过程中发挥作用？启动产生TLE的中间层过程需要什么样的电磁场强度？在正负极性云地闪电放电之间TLE的产生是否存在不对称性？在包含子画面电流和不包含子画面电流的子画面之间，在光发射或驱动闪电参数方面是否存在可识别的差异？回答这些问题将大大提高闪电电离层耦合过程的定量理解，从而提高预测其更大尺度效应的能力。这项研究将利用过去的实验测量以及将用现有仪器进行的观测。精灵和TLE不仅在视觉上壮观。它们也是雷暴中存在的复杂电过程的表现，并将低层大气与高层大气联系起来。