CITE-3 Electra In-Situ Aerosol Data

CITE-3_Aerosol_AircraftInSitu_Electra_Data is the in-situ trace gas data collected onboard the NASA Electra aircraft Chemical Instrumentation Test and Evaluation - 3 (CITE-3) suborbital campaign. Data using chemiluminescence are featured in this collection. Data collection for this product is complete. During 1983-2001, NASA conducted a collection of field campaigns as a part of the Global Tropospheric Experiment (GTE) to develop advanced instrumentation to measure critical atmospheric trace gases and quantify their sources, sinks, and distribution. Among those were the Chemical Instrumentation Test and Evaluation (CITE) missions, which had the overarching goal to test and evaluate the instruments developed for the GTE missions. To accomplish this objective, the CITE missions adopted the methodology of conducting intercomparisons of airborne measurements obtained for the same species by instruments utilizing fundamentally different detection principles (Hoell et al., 1990). The third phase of the CITE mission, CITE 3, occurred in the North and tropical Atlantic Ocean from August-September 1989. Its primary objective was to test and evaluate the capacity to collect reliable measurements of the following sulfur species: sulfur dioxide (SO2), dimethyl sulfide (DMS), carbonyl sulfide (COS), carbon disulfide (CS2), and hydrogen sulfide (H2S). The secondary objective of CITE 3 was to determine the abundance and distribution of major sulfur species over a wide range of atmospheric conditions, including altitude, solar flux levels, atmospheric mixing ratios, and surface source strengths of sulfur in a predominantly marine environment (Hoell et al., 1993). CITE 3 utilized the NASA Electra research aircraft equipped with a suite of instruments for sulfur and ancillary measurements. The two main objectives were addressed through intercomparisons of airborne measurements obtained for the same species but utilizing fundamentally different detection principles in order to have multiple measurements of each of the sulfur species. In some instances, the same detection principle was used, but the method of sample collection and/or analysis procedures were different. A complete payload had the potential of five techniques for SO2, six techniques for DMS, and three techniques for H2S, CS2, and COS. However, due to operational problems or team decisions to focus on specific species during flights, not all measurement techniques were employed at all times (Hoell et al., 1993). There were three phases of field activity in this campaign: (1) intercomparison of sulfur calibration standards, (2) measurements in ambient air over the Northern Atlantic Ocean, and (3) measurements in ambient air over the tropical Atlantic Ocean. Cite 3 was based out of NASA Wallops Flight Facility in Virginia, USA and Natal, Brazil. Each base of operation provided a different environment for intercomparison. Air masses at NAS Wallops Flight Facility were influenced by anthropogenic emissions along the eastern United States compared to the relatively clean marine boundary layer over the ocean off the coast of Natal. As part of the Natal deployment, ozonesondes were launched from the Natal area to provide data on the general state of the atmosphere as well as serve as a frame of reference when compared to the seasonally averaged ozone data from this site. seasonally averaged ozone data from this site. Sulfur gases and their reaction products play important roles in the chemistry of the global troposphere as well as the biogeochemical sulfur cycle. The sulfur database from CITE 3, and the results from both intercomparison studies and photochemical budget studies, significantly enhanced the ability to evaluate the confidence in the existing databases. Detailed description related to the motivation, implementation, and instrument payloads are available in the CITE 3 overview paper. A collection of the publications based on CITE 3 observations are available in the Journal of Geophysical Research special issue: Chemical Instrumentation Test and Evaluation (CITE 3).CITE-3_Aerosol_AircraftInSitu_Electra_Data数据集是NASA Electra飞机在化学仪器测试与评估-3（Chemical Instrumentation Test and Evaluation -3，简称CITE-3）亚轨道飞行任务期间采集的原位痕量气体数据。本数据集重点包含采用化学发光（chemiluminescence）技术获取的数据，且该产品的数据采集工作已完成。 1983-2001年间，NASA作为全球对流层实验（Global Tropospheric Experiment，简称GTE）的一部分开展了一系列野外试验，旨在研发先进仪器以测量关键大气痕量气体，并量化其源、汇及分布特征。其中包括化学仪器测试与评估（Chemical Instrumentation Test and Evaluation，简称CITE）任务，其核心目标是测试和评估为GTE任务研发的仪器。为实现这一目标，CITE任务采用了如下方法：对利用根本不同检测原理的仪器针对同一物种获取的机载测量数据进行比对（Hoell等，1990）。CITE任务的第三阶段（CITE-3）于1989年8月至9月在北大西洋和热带大西洋开展，主要目标是测试和评估对二氧化硫（SO₂）、二甲基硫醚（DMS）、羰基硫（COS）、二硫化碳（CS₂）和硫化氢（H₂S）等硫物种进行可靠测量的能力；次要目标是确定主要硫物种在多种大气条件下的丰度与分布，包括以海洋环境为主区域中硫的海拔、太阳通量水平、大气混合比及地表源强度等条件（Hoell等，1993）。 CITE-3使用配备硫及辅助测量仪器套件的NASA Electra研究飞机，通过对同一物种但采用不同检测原理的机载测量数据进行比对，实现对每种硫物种的多重测量，以达成两大核心目标。部分情况下虽采用相同检测原理，但样品采集或分析程序存在差异。完整有效载荷可支持5种SO₂测量技术、6种DMS测量技术及3种H₂S、CS₂和COS测量技术，但受操作问题或飞行中聚焦特定物种的团队决策影响，并非所有技术始终被采用（Hoell等，1993）。该试验含三个野外阶段：（1）硫校准标准比对；（2）北大西洋环境空气测量；（3）热带大西洋环境空气测量。其基地位于美国弗吉尼亚州NASA沃洛普斯飞行设施与巴西纳塔尔，两地为比对提供不同环境——沃洛普斯气团受美国东部人为排放影响，纳塔尔海岸则为相对清洁的海洋边界层。纳塔尔部署期间发射的臭氧探空仪（ozonesondes）提供了大气总体状态数据，并作为与该站点季节性平均臭氧数据对比的参考框架。 硫气体及其反应产物在全球对流层化学和生物地球化学硫循环（biogeochemical sulfur cycle）中至关重要。CITE-3的硫数据库及比对、光化学收支研究结果，显著提升了评估现有数据库可信度的能力。研究动机、实施过程及仪器有效载荷的详细描述见CITE-3概述论文，基于其观测的系列出版物可在《地球物理研究杂志》特刊《化学仪器测试与评估（CITE-3）》中查阅。