The airborne mass spectrometer AIMS – Part 2: Measurements of trace gases with stratospheric or tropospheric origin in the UTLS

摘要: Abstract. Understanding the role of climate-sensitive trace gas variabilities in upper troposphere and lower stratosphere region (UTLS) their impact on its radiative budget requires accurate measurements. The composition UTLS is governed by transport chemistry stratospheric tropospheric constituents, such as chlorine, nitrogen oxide sulfur compounds. Atmospheric chemical Ionization Mass Spectrometer AIMS has been developed to accurately measure a set these constituents aircraft means ionization. Here we present setup using SF5− reagent ions for simultaneous measurement concentrations HCl, HNO3 SO2  pptv ppmv (10−12 10−6 mol mol−1) range with in-flight online calibration called AIMS-TG (Atmospheric measurements gases). Part 1 this paper (Kaufmann et al., 2016) reports water vapor AIMS-H2O configuration. instrument can be flexibly switched between two configurations depending scientific objective mission. For AIMS-TG, custom-made discharge ion source generation that selectively react HNO3, HONO. HCl are routinely calibrated permeation devices; continuously during flight adding an isotopically labeled 34SO2 standard. In addition, report HONO, which sensitive reaction SF5−. detection limit various gases low 10 pptv at 1 s time resolution overall uncertainty order 20 %. integrated successfully operated DLR research Falcon HALO (High Altitude LOng aircraft). As example, conducted TACTS/ESMVal (Transport Composition LMS/UT Earth System Model Validation) mission 2012 presented, focusing classification influences region. combination other techniques yields comprehensive picture sulfur, chlorine reactive UTLS. different measured exhibit potential gain better understanding origin variability near tropopause.