Arnold Heemink of Delft University of Technology has developed, for more than 40 years, data assimilation techniques for large-scale numerical models. These techniques are based on ensemble Kalman filtering or on variational data assimilation.

Up to 1993, when he was affiliated to Rijkswaterstaat, the main applications were flow and transport problems in coastal seas, and he also developed the data assimilation scheme for the operational storm surge forecasting system in the Netherlands.

When he joined Delft University of Technology in 1993, he worked on real life data assimilation problems in air pollution and reservoir engineering too. More recently, he worked on adjoint-free variational data assimilation schemes using model order reduction techniques.