Stratosphere (ICE-4)

Some atmospheric trace gases (e.g. sulfur dioxide, SO₂) are present in the atmosphere at extremely low concentrations in the sub ppb (parts per billion) range. Still these so-called ultra trace species can have a huge impact on the global radiative budget due to their involvement in aerosol formation processes and/or gas-phase chemical processes. Therefore they are key for the detailed understanding of climatic change which again are of high importance for models predicting the future climatic evolution. However, the reliable measurement of trace species like SO₂ is very difficult and for several still today good global datasets are lacking.

ICE-4 has now redesigned the airborne chemical-ionization mass spectrometer FunMass to be certified and regularly deployed in a multi-instrument container onboard a Lufthansa A-350 passenger aircraft in the frame of the [IAGOS-CARIBIC project] (https://www.caribic-atmospheric.com/).

FunMass will sensitively and accurately measure several trace species (SO₂, organic acids (formic and acetic acid), nitrous and nitric acids (HONO and HNO₃) and hydrogen peroxide (H₂O₂)) thereby delivering spatially highly-resolved distributions in the 10-13km altitude range which is part of the climate relevant upper troposphere and lower stratosphere (UTLS) region. The data sets will cover the mid and tropical latitudes of the globe. For SO₂ these are the first detailed and regular such measurements.

The certification of the complete instrument container is ongoing and first flights will commence until end of 2026, with planned one 4-5 fligh series each month for the coming decade thereby generating a climatologically highly relevant multi-species dataset indispensable for the validation and improvement of climate models.