Stephan works on the development of new methods for fast radiative transfer. He is also involved in the development of fast variational retrieval codes.
Stephan has been heavily involved in the development of the Havemann-Taylor Fast Radiative Transfer Code (HT-FRTC). The HT-FRTC uses Principal Components for the fast (significantly less than a MILLISECOND) simulation of highly resolved monochromatic (0.001 wavenumbers), hyperspectral and/or broadband transmittances, radiances and/or fluxes from satellite, airborne and ground-based sensors across the whole electromagnetic spectrum from the microwave to the ultraviolet.
Stephan has also worked on the development of a variational retrieval scheme in Principal Component Space. This can simultaneously retrieve atmospheric profiles of temperature and humidity as well as surface and cloud properties.
Stephan obtained a first class MSc (Diplom) degree in Physics with minors in Mathematics and Computer Science from the University of Kiel in Germany in 1995.
Since 1996 he worked at the German Aerospace Center (Deutsches Zentrum fuer Luft- und Raumfahrt) in Neustrelitz, Germany on electromagnetic scattering by non-spherical atmospheric particles.
In 1999 he continued this kind of work at the Meteorological Research Flight, a part of the UK Met Office.
Stephan obtained a PhD in Meteorology with "magna cum laude" (with the distinction "opus eximium" for the thesis) from the University of Kiel in Germany in 2000.
Since then he has been a Research Scientist at the UK Met Office on a permanent basis still working at the Meteorological Research Flight which has since been renamed Observations Based Research.