PhD position in atmospheric Physics
Bromine is the second most important halogen for stratospheric photochemistry. It promotes about 30% of the ozone loss in the stratosphere. On a per atom basis, the ozone destruction of iodine is even larger (~200 times larger than chlorine) compared to that of bromine (~60 times larger than chlorine), but owing to its small stratospheric concentration (some 0.1 ppt), its contribution to the loss of stratospheric ozone is small or even negligible (WMO-2018). Both types of halogens enter the stratosphere in varying fractions of various organic and inorganic species, largely depending on the proximity of the natural and in case of bromine also anthropogenic sources. Over the past three decades, our research group developed particular skills to measure the major inorganic halogen species BrO and IO from high-flying aircrafts (e.g., Falcon, HALO, Global Hawk) and high flying research balloons. When these measurements are combined with photochemical modelling and measurements of the organic gases, their total budgets can be established (see the Figure). Backward trajectory modelling using the Lagrangian model CLAMS (https://en.wikipedia.org/wiki/CLaMS) then allows to back-trace the investigated air masses to the relevant source regions of organic halogens. These objectives are the core of our contributions to the ROMIC II, project SCI-HI, funded by the German federal ministry of research (BMFT) for three years, starting in Oct. 2019.
Within the offered Phd thesis, the limb UV/vis skylight spectra measured from aboard the HALO aircaft (https://www.halo.dlr.de/) during a series of past research missions (2012 – 2019) need to be evaluated for the targeted gases (O3, BrO, OClO, IO, NO2, O4, ..) using differential optical absorption spectroscopy (DOAS). Following this, the inferred slant column densities need to be inverted into mixing ratios of the gases using the novel scaling method in conjunction with radiative transfer (McArtim) and CLaMS photochemical transport modelling. Finally, the inferred data
need to be analyzed and interpreted for the objectives given above, as well as other emerging exciting aspects. Skills in Matlab and/or Python and possibly Labview programming as well in atmospheric physics and chemistry are expected.
Through scientific reports given in the peer-reviewed literature, as well as at international/national conferences and project meetings, the PhD work offers great possibilties for becoming a professional in the field of atmospheric spectroscopy, transport and photochemistry. The applicant should have a full master study in Physics, see here https://www.physik.uni-heidelberg.de/studium/Promotion/?lang=en
The PhD thesis is supported by 50% of a German TVL-13 contract.
Applications should be preferably sent by email to:
Prof. Klaus Pfeilsticker
Institut für Umweltphysik