User:Michaela I. Hegglin

I worked since the beginning of my scientific career on the evaluation and quality-assessment of atmospheric observations (in-situ and space-based), and how they can be used to gain knowledge of dynamical, chemical, transport, and mixing processes in the atmosphere. During my PhD at ETH in Zurich, I performed and worked on the interpretation of in-situ aircraft measurements in the upper troposphere/lower stratosphere (UTLS), and these data I used during my Postdoc years at the University of Toronto to validate the performance of satellite instruments and chemistry-climate models. The issue I'm currently most interested in is the influence of stratospheric tracer composition on the troposphere (and vice-versa). For example, my 2009 Nature Geoscience paper 'Large climate-induced changes in ultraviolet index and stratosphere-to-troposphere ozone flux' quantified the influence of climate-induced changes in the strength of the Brewer-Dobson circulation on the stratospheric ozone distribution and with it changes in the stratospheric ozone flux and ultraviolet radiation penetrating to the Earth's surface. With the GEOS-Chem assimilation system, I hope to explore the the importance of a properly resolved stratosphere and its impact on tropospheric tracer composition.