Abstract. We describe the Airborne Mid-Infrared Cavity enhanced Absorption spectrometer (AMICA) designed to measure trace gases in situ on research aircraft using Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS). AMICA contains two largely independent and exchangeable OA-ICOS arrangements, allowing for the simultaneous measurement of multiple substances in different infrared wavelength windows tailored to scientific questions related to a particular flight mission. Three OA-ICOS setups have been implemented to measure OCS, CO₂, CO and H₂O at 2050 cm⁻¹, O₃, NH₃ and CO₂ at 1035 cm⁻¹, and HCN, C₂H₂ and N₂O at 3331 cm⁻¹. The 2050 cm⁻¹ setup has been fully characterized in the lab and successfully used for atmospheric measurements during two campaigns with the research aircraft M55-Geophysica and one with the German HALO aircraft. Nominal measurement precision is 30 ppt for OCS, 1 ppm for CO₂, 3 ppb for CO and 100 ppm for H₂O. The 1035 and 3331 cm⁻¹ arrangements have only partially been characterized and are still in development. The ~100 kg instrument with a typical in-flight power consumption of about 500 VA is dimensioned to fit into one 19 inch rack typically used for deployment inside the aircraft cabin. Its rugged design and a pressurized and temperature stabilized compartment containing the sensitive optical and electronic hardware also allow for deployment in payload bays outside the pressurized cabin even at high altitudes of 20 km. A sample flow system with two parallel proportional solenoid valves of different size orifices allows for precise regulation of cavity pressure over the wide range of inlet port pressures encountered between the ground and maximum flight altitudes. Sample flow on the order of 1 SLM maintained by an exhaust-side pump limits the useful time resolution to about 2.5 s (corresponding to the average cavity flush time).

中文翻译：

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机载中红外腔增强吸收光谱仪（AMICA）

摘要。我们描述了机载中红外腔增强吸收光谱仪（AMICA），该仪器旨在使用离轴集成腔输出光谱（OA-ICOS）原位测量研究飞机上的痕量气体。AMICA包含两个在很大程度上独立且可互换的OA-ICOS装置，从而可以在针对与特定飞行任务相关的科学问题量身定制的不同红外波长窗口中同时测量多种物质。已经实施了三种OA-ICOS设置来测量2050 cm ^-1处的OCS，CO ₂，CO和H ₂ O ，1035 cm ^-1处的O ₃，NH ₃和CO ₂以及HCN，C ₂ H ₂N ₂ O为3331 cm ^-1。2050 cm ^-1的设置已在实验室中进行了全面表征，并在两次使用M55-Geophysica科研飞机和一次德国HALO飞机进行的战役中成功用于大气测量。OCS的标称测量精度为30 ppt，CO ₂为1 ppm，CO为3 ppb，H ₂ O为100ppm。1035和3331 cm ^-1安排仅具有部分特征，并且仍在开发中。约100千克的仪器通常在飞行中的功耗约为500 VA，其尺寸适合于一个19英寸的机架，该机架通常用于飞机机舱内的部署。其坚固的设计以及装有灵敏的光学和电子硬件的加压和温度稳定的隔室，即使在20 km的高空，也可以在加压机舱外部的有效载荷舱中进行部署。带有两个平行的比例孔大小不同的比例电磁阀的样品流系统可在地面和最大飞行高度之间遇到的大范围入口压力范围内精确调节腔压力。