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

凭借这一奖项，研究人员将对2013年5月至6月期间进行的深对流、云和化学实验(DC3)期间收集的数据进行全面研究。DC3收集了美国东南部、大平原南部和科罗拉多州东部半干旱地区三个地区各种对流事件中的云动力学、微物理和化学的综合数据集。这项研究将解决DC3计划的两个主要目标：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“反转”电极性；以及提高我们对闪电产生氮氧化物(NOx)的理解。关于风暴电气结构的工作将利用在DC3获得的全面的多普勒和偏振雷达和闪电测绘网络数据，并将包括受科罗拉多州High Park野火影响的一小部分风暴样本。在改进云化学模型中如何处理闪电产生的NOx的目标下，研究小组将使用闪电总闪光率的闪电映射阵列观测来改进闪光率参数，为旨在估计每一次闪电产生的NOx量的风暴规模预算研究做出贡献，并完善关于闪电产生的NOx被“释放”到风暴中的假设。研究小组将把对砧状云(冻结液滴的集合体)中冰粒类型的详细观察与邻近的深对流联系起来。在这个奖项下，研究团队将开展一些合作来加强这项研究，包括与科学家合作，他们正在使用天气研究预报-化学(WRF-Chem)模式对几个DC3案例进行云化学模拟。这项研究将有助于建立关于云动力学、微物理和带电/闪电之间耦合的知识库。这项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，在这种结构中，正电荷存在于风暴的中层，而不是更典型的结构，即带负电荷的水星存在于中层。利用DC3的综合测量，研究小组还将解决闪电-NOx问题，即量化闪电产生的风暴中NOx的释放量。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进行。因此，这项工作将是跨学科的，将云层物理和大气化学专家聚集在一起。这项工作还将提高我们对深部对流如何影响顶端冰水含量和冰粒类型的理解。因此，这项工作可能有助于更好地理解与强对流有关的钉子的辐射特性。DC3的观测有望促进我们对风暴动力学、微物理和电气化的理解。对这些过程的了解将为改进在云化学模型中考虑闪电产生的NOx(LNOx)的方式提供基础。然后，LNOx在促进对流层上层臭氧这一温室气体方面的作用可以得到改善。总的来说，DC3的结果有望增进我们对深对流对UTLS(上对流层-下平流层)化学成分的影响的理解。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。

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.