Nitrogen fringe aurora over Lyngenfjord, Norway. Photo: Jan R. Olsen,
Nitrogen fringe aurora over Lyngenfjord, Norway. Photo: Jan R. Olsen,


Congratulations on successfully defending your thesis, Dr Hendrickx!

Koen Hendrickx, former PhD student at MISU.
Koen Hendrickx, former PhD student at MISU.

What has been the focus of your research?

– I’ve been studying the impact of the Sun on nitric oxide (NO) concentrations in the upper atmosphere, specifically how NO is produced and destroyed by radiation and energetic particles, and how it is transported to lower altitudes in the polar, winter atmosphere. To do this, I have used new satellite data from SOFIE, an instrument onboard the AIM satellite, which is developed for research on noctilucent clouds. NO is one of the gaseous species that is measured by SOFIE and can be used as a tracer for atmospheric dynamics. Because NO observations are made 15 times per day, each day, it allows us to do some interesting analyses, says Koen Hendrickx.

– We have developed, for example, a diagnostic method to determine the relative importance of the physical drivers of NO throughout the lower thermosphere. Our research shows that at high latitudes, precipitating auroral electrons dominate the variations in NO concentrations, Koen Hendrickx explains. We have also found periods where NO is being produced every 27 days, which is related to the strong periodicity of 27 days in the precipitation of these auroral electrons, Koen Hendrickx continues.

From a broader perspective, what is the contribution of your research to climate research?

– The broader impact of this topic is connected to the influence of the Sun on the middle and upper atmosphere. As current climate models extend their highest altitudes to the upper regions of the atmosphere, the more important the role of the Sun becomes and the more important it is to correctly represent these influences in climate models. This is especially true during winter time in the polar regions, since NO particles descend from the upper to the middle atmosphere within the polar vortex and have the possibility to destroy stratospheric ozone in a very efficient way, says Koen Hendrickx.

How was the road to the PhD title for you?

– I started my PhD studies in autumn 2013 and there have, of course, been highs and lows along the way, but this is an innate part of doing research. Looking back on it now, it may seem like your research has been on a straight line, but it never was: it’s a path with many sideways and it is important to remember that. I would say it’s best to try out different things, be that methods, datasets, courses, summer schools or conferences, but also to be fine when some of these things don’t work out, Koen Hendrickx advices.

– The biggest challenge is figuring out if your findings will lead to something, and knowing when to pursue and when to let go. The supervisor has such an important to play here, especially in the beginning of your studies, and luckily for me, I had a great supervisor (ed: Linda Megner)! Also the international environment at MISU, with many researchers and a large IMI network, has helped a lot. You always encounter new opinions, which helps to give new perspectives on your research. One such encounter I had was with Dave Siskind in 2014, which eventually led me to using the SOFIE data.

What’s your next stop?

– I would very much like to continue with science, and me and my family would like to stay in Scandinavia. Looking for Postdoc positions and starting to write proposals are the next logical steps to undertake. For the immediate future, however, I will enjoy my parental leave, spending time with my daughter this spring and summer, Koen Hendrickx concludes.