Timothy N. Palmer

The 2018 Lewis Fry Richardson Medal is awarded to Timothy N. Palmer for his fundamental contributions to the conception and practical implementation of a system for ensemble weather prediction and the recent development of a similar probabilistic approach to climate.

Tim Palmer’s main contribution has been to pioneer, along the lines opened up by Edward Lorenz, the application of ideas from nonlinear chaotic dynamical systems to the problem of numerical weather prediction. A major achievement of his has been the conception and development of an Ensemble Prediction System at the European Centre for Medium-Range Weather Forecasts. Together with similar work done at the same time at the US National Centers for Environmental Prediction, this has introduced explicit quantitative operational estimates of state-dependent predictability. It has played a leading role in the development of similar prediction systems in a number of meteorological services and has led to a much more accurate evaluation than hitherto of the confidence that can be given to the predictions.

Palmer has continued to extend the scope of ensemble, and more generally probabilistic, prediction, with the introduction of stochastic physics in order to represent the impact of uncertainties in the prediction model itself, in addition to uncertainties in the initial conditions. He also applied the tools he had developed to seasonal and climate prediction.

Palmer’s interests go beyond geophysics, as for example in quantum physics. He has also recently looked into the question of using scale-dependent computational precision to improve the cost-efficiency of numerical weather prediction, a question which will take an increasing importance in the coming years.

For all these reasons, Palmer is a worthy recipient of the EGU 2018 Lewis Fry Richardson Medal.