Project Details
Projekt
Evaluation, dissemination, and interpretation of the mini-DOAS data collected during the HALO ASCCI mission, and of those collected during previous polar missions
Subject Area
Atmospheric Science
Term
since 2025
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 552703126
The proposed research aims at the data analysis, dissemination and interpretation of measurements that the mini-DOAS instrument on board the research aircraft HALO will record in the ASCCI campaign in spring 2025 and has already recorded in previous polar campaigns such as SOUTHTRAC and POLSTRACC. The mini-DOAS instrument is a passive remote sensing instrument that simultaneously measures and spectrally analyzes sky scattered light in the UV/vis/NIR spectral range in the nadir and limb directions from aboard HALO. Using differential optical absorption spectroscopy (DOAS), the measurements can be used to determine the concentrations of important trace gases at flight altitude, as well as vertical profiles and vertical columns below the aircraft, whereby some of the trace gases measured cannot be detected with other measurement methods (BrO, OClO, IO,) or are difficult to detect (NO2, HONO, CH2O, C2H2O2, and C3H4O2*). The focus of the project proposed here is on determining the total bromine content of the stratosphere and the ozone depletion rate through the catalytic ClOx/BrOx cycle in the polar vortex. For this purpose, BrO column concentrations will be derived from the mini-DOAS spectra in the UV, correlated with the air mass age (via the tracer SF6), emission regions and transport routes to continue the long-term trend measurements of stratospheric bromine. Air masses within the polar vortex will be analyzed for catalytic ozone depletion using the simultaneous mini-DOAS measurements of OClO and in conjunction with ClOx, ClONO2 and HCl (measured by the partner instruments on HALO). In particular, our measurements help to calculate the ozone depletion rates through the ClOx/BrOx cycle under variable conditions using the CLaMS model of the ASCCI partner FZ Jülich.
DFG Programme
Infrastructure Priority Programmes
