A novel, balloon-borne UV–Vis spectrometer for direct sun measurements of stratospheric bromine

• DOI: 10.5194/amt-17-4507-2024
• Publication Date: 2024-07-29T13:47:53Z
• Authors: Karolin Voss; Philip Holzbeck; Klaus Pfeilsticker; Ralph Kleinschek; Gerald Wetzel; Blanca Fuentes An...; Michael Höpfner; Jörn Ungermann; Björn-Martin Sinn...; André Butz
• Keywords: Mixing ratio

Abstract. We report on a novel, medium-weight (∼ 25 kg) optical spectrometer coupled to an automated sun tracker for direct observations from azimuth-controlled balloon platforms weighing approximately 12 kg. It is designed measure suite of UV–Vis absorbing gases relevant in the context stratospheric ozone depletion using differential absorption spectroscopy (DOAS) method, i.e. O3, NO2, BrO, OClO, HONO, and IO. Here, we describe design major features instrument. Further, instrument's performance during two deployments Esrange near Kiruna (Sweden) 21 August 2021 Timmins (Ontario, Canada) 23 2022 discussed along with first results concerning inferred mixing ratios BrO above float altitude. Using photochemical correction partitioning bromine ([BrO]/[Bry]) obtained by chemical transport simulations, total load [Bry] amounts (17.5 ± 2.2) ppt, purely statistical error amounting 1.5 ppt (5.5 1.0)-year old air. The latter simultaneous measurements N2O GLORIA (Gimballed Limb Observer Radiance Imaging Atmosphere) mid-IR instrument, resulting entry investigated air mass early 2017 1 year.