This post was jointly authored with Prof Sebastian Reich, University of Potsdam. An edited version will appear on the Cambridge University Press blog page.
Computer generated forecasts play an important role in our daily lives, for example, predicting weather or economies. Forecasts combine computational models of relevant dynamical processes with measured data. Errors are always present through incomplete observations plus imperfections in the model, so forecasts must be constantly calibrated with new data. In the geosciences, this is called data assimilation. The introduction of probabilistic approaches to forecasting and data assimilation has been a major breakthrough in the field, facilitated by powerful supercomputers.