Research Motivation: The Earth System is changing and humans are involved in many ways. The current geological era has therefore been named 'The Anthropocene'. There is an urgent need to efficiently monitor the changes and to provide scientific interpretations to society. Climate change, diminishing biodiversity, global-scale air pollution, and ozone layer depletion are the most pressing environmental issues directly related to the rapid changes in global atmospheric composition which are caused by unsustainable human activities. In addition to my research activities I contribute to the KNMI organization as the secretary for the Research Council, coordinator integrity and advisor for sustainability of the organization.
The research is both nationally and internationally oriented. Cooperation within national and international research project teams is key to progress in scientific understanding of the atmosphere and environment.
My research is on atmospheric composition and its interaction with meteorology, with a focus on climate change, the ozone layer, air pollution, and the physical parameters that determine the oxidizing ('cleansing') capacity of the atmosphere. Methane and tropospheric ozone, mainly formed through enhanced methane emissions, constitute a significant contribution to anthropogenic climate forcing next to CO2. Satellite observations increasingly help to complement and improve current emission estimates for greenhouse gases as well as important precursor gases including nitrogen oxides (NOx), carbon monoxide (CO), sulphur dioxide (SO2), formaldehyde (CH2O) and ammonia (NH3). Enhanced ozone levels at the surface are harmful for health and limit agricultural yields. Biogenic emissions are changing through climate change and land use changes. Excessive deposition of nitrogen compounds has important environmental consequences and contributes to degradation in biodiversity. The EC Earth Earth System model is being developed in Europe to improve the study of the interaction of past, present-day and future emission and atmospheric composition changes with climate and the other elements of the Earth system. Lotos-Euros is the regional model used for air quality forecasts as part of CAMS regional ensemble. Harmonie is the regional weather model used for weather warnings.