Studies of Convection, Microphysics and Lightning in the Deep Convective Clouds and Chemistry Experiment (DC3)

深对流云中的对流、微物理和闪电研究及化学实验（DC3）

• 批准号: 1429925
• 负责人: Steven Rutledge
• 金额: $ 67.53万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2018-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1429925&HistoricalAwards=false
• 关键词: Studies; Convection; Microphysics; Lightning; Deep

With this award, the investigators will carry out comprehensive studies of the data collected during the Deep Convection, Clouds and Chemistry Experiment (DC3) conducted during May-June 2013. DC3 collected a comprehensive dataset on cloud dynamics, microphysics and chemistry in a variety of convective events, over three regions, the southeast U.S., the Southern Great Plains and over the semi-arid region of eastern Colorado. The research will address two of the overarching goals of the DC3 program; understanding the gross electrical structure of storms and why particular storms have a so-called "inverted" electrical polarity; and improving our understanding regarding the production of Nitrogen Oxides (NOx) by lightning. The work concerning the electrical structure of storms will utilize comprehensive Doppler and polarimetric radar and lightning mapping network data obtained in DC3 and will include a small sample of storms affected by the High Park wildfire in Colorado. Under the objective to improve how lightning-generated NOx is handled in cloud-chemistry models, the research team will use Lightning Mapping Array observations of total lightning flash rates to improve flash rate parameterizations, contribute to storm scale budget studies aimed at estimating the amount of NOx produced per lightning flash, and refine assumptions regarding where the lightning-generated NOx is "released" into the storm. The research team will relate detailed observations of ice particle types in anvil clouds (aggregates of frozen droplets) to the adjacent deep convection. Under this award, the research team will develop a number of collaborations to enhance this research, including collaborations with scientists that are conducting cloud-chemistry simulations of several DC3 cases using the Weather Research Forecasting-Chemistry (WRF-Chem) model.This research will contribute to the knowledge base regarding the coupling between cloud dynamics, microphysics and electrification/lightning. The research will utilize state of the art radar and lightning mapping information in order to improve our understanding of so-called "inverted" charge structures where positive electrical charge resides in the storm mid-levels, opposed to the more typical structure where negatively-charged hydrometeors resides at mid-levels. Utilizing the comprehensive measurements from DC3,the research team will also address the lightning-NOx problem, that is, quantifying the amount of NOx released in a storm produced by lightning. This work will be done from the point of view of improving required parameterizations for these processes in cloud-chemistry models. Hence this work will be interdisciplinary in nature, bringing together cloud physics and atmospheric chemistry specialists. This work will also improve our understanding as to how deep convection contributes to anvil ice water contents and ice particle types. Hence this work may lead to a better understanding regarding the radiative properties of anvils attached to strong convection. DC3 observations are expected to advance our understanding regarding storm dynamics, microphysics and electrification. Knowledge of these processes will provide a basis for improving the manner by which lightning-generated NOx (LNOx) is considered in cloud-chemistry models. The role of LNOx in contributing to upper tropospheric ozone, a greenhouse gas, can then be improved. In general DC3 results are expected to improve our understanding regarding the impact of deep convection on the chemical composition of the UTLS (upper troposphere-lower stratosphere). Experimental data from the DC3 project will provide important datasets for model comparison exercises and assessment reports.

凭借这一奖项，研究人员将对 2013 年 5 月至 6 月进行的深对流、云和化学实验 (DC3) 期间收集的数据进行全面研究。DC3 收集了各种领域的云动力学、微物理和化学的综合数据集。对流事件发生在美国东南部、南部大平原和科罗拉多州东部半干旱地区三个地区。该研究将解决 DC3 计划的两个总体目标；了解风暴的总体电气结构以及为什么特定风暴具有所谓的“反向”电极性；并提高我们对闪电产生氮氧化物 (NOx) 的了解。有关风暴电结构的工作将利用在 DC3 中获得的综合多普勒和偏振雷达以及闪电测绘网络数据，并将包括受科罗拉多州 High Park 野火影响的风暴的小样本。为了改善云化学模型中闪电产生的氮氧化物的处理方式，研究小组将使用闪电测绘阵列对总闪电频率的观测来改进闪电频率参数化，为旨在估计闪电数量的风暴规模预算研究做出贡献。每次闪电产生的氮氧化物，并完善有关闪电产生的氮氧化物“释放”到风暴中的位置的假设。研究小组将对砧云（冷冻水滴聚集体）中的冰粒子类型的详细观察与邻近的深对流联系起来。根据该奖项，研究团队将开展多项合作来加强这项研究，包括与使用天气研究预测化学 (WRF-Chem) 模型对几个 DC3 案例进行云化学模拟的科学家进行合作。这项研究将为有关云动力学、微物理和电气化/闪电之间耦合的知识库做出贡献。该研究将利用最先进的雷达和闪电测绘信息，以提高我们对所谓的“倒置”电荷结构的理解，其中正电荷驻留在风暴中层，而不是更典型的负电荷结构。水凝物位于半山。利用DC3的综合测量，研究小组还将解决闪电-氮氧化物问题，即量化闪电产生的风暴中释放的氮氧化物的量。这项工作将从改进云化学模型中这些过程所需的参数化的角度来完成。因此，这项工作本质上是跨学科的，汇集了云物理学和大气化学专家。这项工作还将增进我们对深对流如何影响砧冰水含量和冰粒类型的理解。因此，这项工作可能会导致更好地理解强对流砧的辐射特性。 DC3 观测预计将增进我们对风暴动力学、微物理和电气化的理解。了解这些过程将为改进云化学模型中考虑闪电产生的氮氧化物 (LNOx) 的方式提供基础。 LNOx 在对流层上层臭氧（一种温室气体）的贡献中的作用可以得到改善。 总的来说，DC3 结果预计将提高我们对深对流对 UTLS（对流层上层-平流层下层）化学成分影响的理解。 DC3项目的实验数据将为模型比较练习和评估报告提供重要的数据集。