Airborne multi-axis DOAS measurements of atmospheric trace gases on CARIBIC long-distance flights

Abstract

Abstract. A DOAS (Differential Optical Absorption Spectroscopy) instrument was implemented and operated onboard a long-distance passenger aircraft within the framework of the CARIBIC project (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container).The instrument was designed to keep weight, size and power consumption low and to comply with civil aviation regulations. It records spectra of scattered light from three viewing directions (nadir, 10 • above and below horizon) using a miniaturized telescope system. The telescopes are integrated in the main pylon of the inlet system which is mounted at the belly of the aircraft. Fibre bundles transmit light from the telescopes to spectrograph-detector units inside the DOAS container instrument. The latter is part of the removable CARIBIC instrument container, which is installed monthly on the aircraft for a series of measurement flights.During 30 flight operations within three years, measurements of HCHO, HONO, NO 2 , BrO, O 3 and the oxygen dimer O 4 were conducted. All of these trace gases except BrO could be analysed with a 30 s time resolution. HONO was detected for the first time in a deep convective cloud over central Asia, while BrO, NO 2 and O 3 could be observed in tropopause fold regions. Biomass burning signatures over South America could be seen and measurements during ascent and descent provided information on boundary layer trace gas profiles (e.g. NO 2 or HCHO).

Composition and evolution of volcanic aerosol from eruptions of Kasatochi, Sarychev and Eyjafjallajökull in 2008–2010 based on CARIBIC observations

“…Concentrations of SO 2 are obtained from the CARIBIC DOAS (Differential Optical Absorption Spectroscopy) instrument (Dix et al, 2009) (Heue et al, 2011). Particle size distributions are measured with an integrated OPC (Optical Particle Counter), which measures particles with a diameter in the range of approximately 0.1-1µm.…”

The Heidelberg Airborne Imaging DOAS Instrument (HAIDI) – a novel imaging DOAS device for 2-D and 3-D imaging of trace gases and aerosols

“…During recent decades a variety of airborne Differential Optical Absorption Spectroscopy (DOAS) measurements were reported (e.g., Wahner et al, 1990;Pfeilsticker and Platt, 1994;McElroy et al, 1999;Petritoli et al, 2002;Melamed et al, 2003;Bruns et al, 2004;Heue et al, 2005;Wang et al, 2005;Bruns et al, 2006;Wang et al, 2006;Heue et al, 2008;Dix et al, 2009;Merlaud et al, 2011;PradosRoman et al, 2011;Merlaud et al, 2012;Baidar et al, 2013), taking place at different flight altitudes and regions of the globe. The aim of these measurements ranged from studies of stratospheric chemistry to tropospheric point source emissions, but only a few of them used Imaging-DOAS (I-DOAS) techniques to acquire 2-dimensional spatially resolved trace gas distributions (e.g., Heue et al, 2008;Kowalewski and Janz, 2009;Popp et al, 2012).…”

Mobile MAX-DOAS observations of tropospheric trace gases

“…In recent years Multi-AXis-Differential Optical Absorption Spectroscopy (MAX-DOAS) observations have become a widely and successfully used technique for the remote sensing of tropospheric trace gases and aerosols (Leser et al, 2003;Van Roozendael et al, 2003;Wittrock et al, 2003; Correspondence to: T. Wagner (thomas.wagner@mpch-mainz.mpg.de) Hönninger et al, 2004a, b;Sinreich et al, 2005;Heckel et al, 2005;Frieß et al, 2006;Fietkau et al, 2007;Theys et al, 2007;Wagner et al, 2004Wagner et al, , 2007aWagner et al, , b, 2009Irie et al, 2008). MAX-DOAS instruments observe scattered sun light under different (mostly slant) viewing angles, providing high sensitivity to tropospheric trace gases and aerosols.…”