RAPID: Measurements of Hydroxyl Radicals, Sulfuric Acid, sCIs, Hydroperoxy Radicals and Organic Peroxy Radicals on the C-130 during FRAPPE

这项工作包括在2014年7月16日至8月16日在科罗拉多州北部前山脉大都会区进行的前山脉空气污染和光化学实验（FRAPPE）现场活动期间，在NSF/NCAR C-130飞机平台上部署一个四通道化学电离质谱仪（CIMS）系统。FRAPPE是由国家大气研究中心（NCAR）的研究人员领导的一项运动，有许多大学科学家参与。FRAPPE活动将与NASA的discovery - aq（从与空气质量相关的柱状和垂直分辨率观测中获取地表条件信息）项目同时进行。通过这项工作测量的化学物质包括OH（羟基自由基）、HO2（羟基自由基）和HO2+RO2（羟基+有机过氧自由基）、H2SO4（硫酸）和sCIs（烯烃与臭氧- O3反应产生的稳定克里基中间体的总和）。这些测量将改善在活动期间采样气团氧化能力的时空变化特征。它们还将有助于限制硫酸在气溶胶形成和生长中的作用，并量化sCIs在城市环境中作为氧化剂的重要性。羟基自由基（OH）是低层大气中的主要氧化剂，也是引起臭氧形成的最重要的氧化剂。在这项研究中进行的测量将对模拟和预测空气质量以及确定科罗拉多州北部前山脉大都会地区的臭氧来源作出重要贡献。这一努力预计将导致改善在城市环境中发生的化学过程的模型表示。

This effort involves the deployment of a four-channel chemical ionization mass spectrometer (CIMS) system on the NSF/NCAR C-130 aircraft platform during the Front Range Air Pollution and Photochemistry Experiment (FRAPPE) field campaign scheduled to take place from July 16-August 16, 2014 in the Colorado Northern Front Range Metropolitan Area. FRAPPE is a campaign being lead by researchers from the National Center for Atmospheric Research (NCAR), with the participation of many university scientists. The FRAPPE campaign will run concurrently with the NASA DISCOVER-AQ (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality) project.Chemical species to be measured through this effort include OH (hydroxyl radicals), HO2 (hydroperoxy radicals) and HO2+RO2 (hydroperoxy plus organic peroxy radicals), H2SO4 (sulfuric acid), and sCIs (the sum of stabilized Criegee radical Intermediates from the reactions of alkenes with ozone - O3). These measurements will improve characterization of the spatial and temporal variability of the oxidizing capacity of the sampled air masses during the campaign. They will also help to constrain the role of sulfuric acid in aerosol formation and growth, and quantify the importance of sCIs as an oxidant in the urban environment.The hydroxyl radical (OH) is the main oxidant in the lower atmosphere and the most significant one causing the formation of ozone. The measurements made in this study will make a vital contribution to modeling and forecasting air quality and in determining the sources of ozone in the Colorado Northern Front Range Metropolitan area. This effort is expected to lead to improved model representations of chemical processes occurring in the urban environment.