May 16 2017 02:30 PM
May 16 2017 03:30 PM
A seminar on "Observing the atmosphere: a holistic approach" by Mikael Ehn, Department of Physics, University of Helsinki was hosted this Tuesday by Prof. Mani Sarathy of the Clean Combustion Research Center.
Dr. Ehn explained how comprehensive measurement stations can be used to tackle the complexity of atmospheric processes. He gave an in-depth overview of how SMEAR station (Station for Measuring Earth-Atmosphere Relations) help in the observations of the formation of particulate matter. He also described the future goals of a comprehensive network of SMEAR stations covering the entire globe.
Describing the atmosphere poses a grand challenge for scientists. Both biogenic and anthropogenic sources continuously emit a multitude of compounds into the atmosphere. While these emissions are transported with moving air masses into other regions, they at the same time can undergo reactions either leading to their removal or to completely new compounds. The emissions and products can interact with the biosphere or hydrosphere, potentially impacting future emissions. Such feedbacks are extremely hard to quantify, yet they can make a tremendous impact on both air quality and climate. Acidification, erosion, climate change, the ozone hole, are only a few examples of how anthropogenic impacts have caused disturbances in the delicate Earth system, which were not foreseen and which remain hard to quantify.
Mikael Ehn is an associate professor in experimental atmospheric physical chemistry at the University of Helsinki (UHEL), Finland, since December 2016. He received his MSc (2005) and PhD (2010) degrees at the department of physics at UHEL. In 2011-2012 he conducted postdoctoral research at the Institute for Energy and Climate Research in Jülich, Germany, where he continued his PhD work on applying mass spectrometric techniques to study atmospheric trace species important for aerosol particle formation. The main result of this work was published in Nature in 2014, describing the existence and formation pathways of extremely oxidized organic compounds in the atmosphere, and their potential contribution to organic aerosol. In 2013 he returned to UHEL and worked as a university lecturer until 2016. He also received the prestigious European Research Council Starting Grant in 2015, aiming at achieving carbon closure between organic emissions and their reaction products in gas and aerosol phases in the atmosphere.