Atmospheric methane and carbon dioxide concentrations measured during ALKOR cruise AL575 on 2022-07-04@en

Atmospheric carbon dioxide (CO2) and methane (CH4) concentrations were monitored during AL575 cruise on 2022-07-04 using a cavity ring down spectrometer (Picarro G2301-f CRDS) and GEOMARs 'Atmospheric Intake System' (AIS). The Picarro/AIS system was installed in the wet laboratory (starboard, main deck) of RV ALKOR and was connected by an aluminium tube to an air inlet nozzle placed at the bow of RV ALKOR. The air was pumped via the AIS intake tube with a flow rate of 2.67 litre per minute to the Picarro analyser. The atmospheric CH4, CO2, and water vapour concentrations were determined in real time at 2-3 Hz sampling rate. A time offset of 87 seconds between the air intake nozzle at the bow (6 m above sea surface) and the actual gas measurement at the Picarro was determined and the calculated flow rate considered, when correlating the gas data with navigation and weather data provided by the WERUM dship repository (https://dship.geomar.de). The weather data is published separately at doi:10.1594/PANGAEA.983833 .2022年7月4日的AL575航次期间，研究人员使用腔环衰光谱仪（cavity ring down spectrometer，Picarro G2301-f CRDS）与GEOMAR的大气进气系统（Atmospheric Intake System，AIS）对大气二氧化碳（carbon dioxide, CO₂）与甲烷（methane, CH₄）浓度开展了监测。该Picarro/AIS集成系统安装于RV ALKOR号研究船的湿实验室（右舷主甲板），并通过铝制管路连接至设于该船船艏的进气喷嘴。空气经AIS进气管路以2.67升每分钟的流速泵送至Picarro分析仪，以2~3赫兹的采样率实时测定大气甲烷、二氧化碳与水汽浓度。经测定，船艏进气喷嘴（距海面6米）与Picarro分析仪处的实际气体测量值之间存在87秒的时间偏移；在将气体数据与WERUM dship知识库（https://dship.geomar.de）提供的导航及气象数据进行关联时，已将该时间偏移与计算得到的流速参数纳入校正考量。本次观测的配套气象数据已另行发表，数字对象标识符（DOI）为10.1594/PANGAEA.983833。