Prof Dr. A. Pier Siebesma is a full-time professor at the Technical University of Delft  (TUD) on the theme “Atmosphere, Weather & Climate” and chair of the department of Geoscience and Remote Sensing.  He also  has a one-day affiliation at the Royal Netherlands Meteorological Institute (KNMI).

He received his PhD in 1989 from the University of Groningen on "Multifractals, Multiplicative Processes and Turbulence". After this he worked as a Post-Doc at the Forschungszentrum Julich GmbH, Germany on "the dynamics on non-linear coupled maps". He then joined in 1990 the Royal Netherlands Meteorological Institute (KNMI) where he has been working on the modeling and parameterization of dry and moist convection and cloud related processes ever since.

His main interest is in the role of clouds and convection in climate and weather and has developed improved convective parameterizations for the global weather prediction model of the European Centre for Medium Range Weather Forecasts (ECMWF) where he has worked as a consultant.  His main interest is in the understanding, modeling and parameterization of cloud related processes, including cloud physics, cloud dynamics, cloud structures, and moist convection. He has been involved in Past Field Campaigns (RICO, BBC, EUREC4A), and is a specialist in development and use of Large Eddy Simulations (LES) to develop parameterizations for operational weather and climate models and in the evaluation of the performance of these parameterisations. He has been the coordinator of the FP7 European Project  Euclipse (European Union Cloud Intercomparison, Process Study & Evaluation Project). More recently his focus is on the direct use of LES for  weather and climate. His group was the first to produce realistic large eddy simulations of various different weather regimes over a domain as large as the Netherlands. He has published over 100  peer-reviewed papers.