Field Measurements for Understanding Atmospheric Oxidation Generated by Electrical Discharges

该项目的目标是使用紫外线辐射通量测量来确定在雷暴天气下树木上的电晕和高压输电线路上的来源产生的氢氧化物(HOX)。由于很难获得直接的HOX测量，使用日冕紫外线辐射作为HOX生产的替代物可以帮助建立对电力产生的HOX对大气氧化的贡献的理解。氢氧化物(尤其是羟基自由基)是控制一氧化碳等有毒气体和甲烷等与气候有关的气体浓度的重要氧化物种。在此之前，该项目团队进行了实验室研究，以测量金属物体和不同类型树叶上的电晕放电产生的Hox排放。在这个项目中，他们将探索雷暴和相关带电铁砧中紫外线排放的现场测量。他们计划使用以下两种方法：(1)使用日盲紫外线相机和该团队最近建造的日冕观测望远镜系统进行地面测量；(2)使用小型日盲光探测器和摄像机，在气球上测量180-195 nm波段和240-280 nm波段的紫外线辐射，以及测量气压、温度、露点温度、声音和GPS位置。从气球的放电中测得的紫外线辐射将量化雷暴单体和砧座中的紫外线辐射场，从而产生HOX。该项目团队的目标是：(1)确保已确定所有重要的大气产生HOX的放电；以及(2)大幅减少计算大气放电对大气氧化的影响的不确定性。该项目包括支持一名本科生和研究生，以及一名博士后，他们将接受培训，参与计划中的研究。这一努力具有巨大的潜力，可以在大气化学和物理气象学、林业、植物生物学和电气工程之间架起新的跨学科研究努力的桥梁。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The goal of this project is to use UV radiation flux measurements to determine the production of hydrogen oxide radicals (HOx) from sources such as corona on trees under thunderstorms and on high voltage electrical power transmission lines. Because direct HOx measurements are difficult to obtain, the use of coronal UV radiation as a surrogate for HOx production can help build an understanding of the contribution of electrically generated HOx to atmospheric oxidation. Hydrogen oxide radicals (especially the hydroxyl radical OH) are important oxidizing species that control the concentrations of toxic gases like carbon monoxide and climate relevant gases like methane.Previously, the project team conducted laboratory studies to measure HOx emissions from electrical and corona discharges on metal objects and on different types of tree leaves. In this project, they will explore field measurements of UV emissions from and in thunderstorms and associated electrified anvils. They plan to use the following two approaches: (1) ground-based measurements using a solar-blind UV camera and a Corona Observing Telescope System recently built by the team; and (2) balloon-borne measurements of UV radiation in the 180-195 nm band and the 240-280 nm band using small solar-blind detectors accompanied by a video camera, and measurements of pressure, temperature, dewpoint temperature, sound, and GPS location. The UV radiation measured from electrical discharges from balloons will quantify the UV radiation field, and thus HOx production, in thunderstorm cells and anvils. The project team aims to: (1) ensure that all significant atmospheric HOx-producing electrical discharges have been identified; and (2) substantially reduce the uncertainties in calculating atmospheric electrical discharge impacts on atmospheric oxidation.The project includes support for an undergraduate and graduate student, and a postdoc, who will be trained to participate in the planned research. This effort has great potential for new interdisciplinary research efforts that bridge between atmospheric chemistry and physical meteorology, forestry, plant biology, and electrical engineering.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.