Collaborative Research: Airborne Hydrogen Peroxide and Methylhydroperoxide Measurements during the Deep Convective Clouds and Chemistry (DC3) Experiment

在2012年5 - 6月的“深层对流云和化学”（DC3）野外活动期间，将使用搭载在NSF/NCAR湾流V研究飞机上的新型化学电离质谱（CIMS）仪器对过氧化氢和甲基过氧化氢进行测量。两种过氧化物的测量将在10赫兹下进行，允许水平和垂直样品分辨率分别为20米和2米。将通过入口不断添加同位素标记的标准气体，以便在压力、温度、水蒸气和其他环境变量的所有变化下为两种物种提供一致的校准。将使用地面湿化学校准系统进行广泛的任务前、集成、测试战斗和部署评估和比较。DC3空气过氧化氢观测将提供：2)对流层上层和平流层下层奇氢化学的限制性资料，3)中纬度大陆云对奇氢前体垂直输送的限制性资料，4)云滴和水成物清除可溶性物质的限制性资料。5)在有和没有闪电添加氮氧化物的情况下对流层上层对流气团化学老化的探测；6)主题1-5在云风暴性质（如云底温度、垂直速度、冻结水平和冰川作用以及闪电）上的变化特征。结果将对对流层氧化剂和臭氧化学及其区域-全球分布具有重要意义；低温、低比湿和混合光照条件下的非均相气-气溶胶化学；气溶胶化学演化及其区域-全球分布；最终影响到空气质量和气候。该仪器系统新颖，代表了机载过氧化氢仪器的重大进步。1名博士后、1名研究生和1名或多名本科生参加实验。数据将在国家大气研究中心存档，结果将在同行评议的期刊上发表。

Measurements of hydrogen peroxide and methylhydroperoxide will be made using a new chemical ionization mass spectrometry (CIMS) instrument on board the NSF/NCAR Gulfstream V research aircraft during the Deep Convective Clouds and Chemistry (DC3) field campaign in May-June 2012. Measurements of the two peroxides will be made at 10 Hz allowing horizontal and vertical sample resolution on the order of 20 meters and 2 meters, respectively. Through-the-inlet isotopically-labeled standard gas additions will be made continuously to provide coincident calibration for both species under all encountered variations in pressure, temperature, water vapor and other environmental variables. Extensive pre-mission, integration, test fight, and deployment evaluations and comparisons will be made using a ground-based wet-chemical calibration system.The DC3 airborne peroxide observations will provide: 1) distributions of these species in and around isolated deep convective clouds, 2) constraining data on odd-hydrogen chemistry in the upper troposphere and lower stratosphere, 3) constraining data on vertical transport of odd-hydrogen precursors by deep mid-latitude continental clouds, 4) constraining data on the scavenging of soluble species by cloud droplets and hydrometeors, 5) a probe of convected air-mass chemical aging in the upper troposphere with and without lightning-added nitrogen oxides, and 6) characterization of the variance of topics 1-5 across cloud-storm properties such as cloud base temperature, vertical velocity, freezing level and glaciation, and lightning. Results will be significant to tropospheric oxidant and ozone chemistry and their regional-to-global distributions; to heterogeneous gas-aerosol chemistry under cold, low specific humidity, and mixed sunlight conditions; to aerosol chemical evolution and their regional-to-global distributions; and ultimately to air quality and climate. The instrument system is novel and represents a significant advance in airborne peroxide instrumentation. One post-doctoral fellow, one graduate student and one or more undergraduate students will participate in the experiment. Data will be archived at the National Center for Atmospheric Research and results published in peer-reviewed journals.