Professor Timothy Palmer has been awarded the World Meteorological Organization’s top award, the IMO prize, for his outstanding contribution to meteorology, and in particular his role in developing probabilistic ensemble prediction methods for forecasting on all timescales. The IMO Prize originates from the International Meteorological Organization, the predecessor to WMO. The IMO Prize is awarded annually and the first was presented to Dr Th. Hesselberg of Norway in 1956.
In 1985, with colleague James Murphy, Professor Palmer developed the world’s first operational ensemble forecast system, for monthly forecasting at the UK Met Office. The ensembles provided probabilistic estimates of large-scale weather regimes and these were combined with forecasts from statistical-empirical models. Professor Palmer brought these ideas to the European Centre for Medium Range Weather Forecasts (ECMWF) in 1986. As Section and Division Head, he led the work leading to the operational implementation of the ECMWF medium-range ensemble in 1992. Professor Palmer and his team developed innovative techniques to ensure the ensembles were reliable. He strongly lobbied for the extension of the ensemble forecast systems to the seasonal timescales and was head of the division that developed the ECMWF seasonal forecast system.
In the 1990s and early 2000s, he led the EU PROVOST and DEMETER projects which developed some of the first multi-coupled-model ensemble forecast systems in the world (now the backbone of IPCC). The present-day Copernicus multi-model seasonal ensemble is a direct result of DEMETER.
Professor Palmer has been a tireless advocate of seamless weather and climate prediction. He has advocated the use of seasonal forecasts to calibrate climate attribution studies. Because climate models have systematic errors in simulating long lived weather regimes (such as blocking anticyclones), attribution studies based on events (such as heat waves) associated with these regimes may not be fully reliable. Attribution probabilities can be adjusted according to the reliability of the seasonal forecast ensembles for these regimes.
The citation recognises: ‘Ensemble prediction is an almost universally used in weather prediction today, on all timescales. Developing reliable ensembles lies at the heart of many weather service strategic plans. Importantly it is completely transforming the way in which disaster relief agencies operate. Now finance can be provided to regions at risk of extreme weather if the ensemble-based probabilities exceed some pre-determined threshold. This allows these agencies to become proactive, rather than merely wait for the weather event to occur and provide aid retroactively. Improving ensemble systems will be vital to make society more resilient to the new extremes of weather associated brought about by climate change.’
As laureate, Professor Palmer will deliver a keynote lecture at the Executive Council meeting in 2024; he joins a distinguished list of previous winners including Professor Emeritus Edward Norton Lorenz (2000), Sir John Houghton (1998), Professor Jule Gregory Charney (1971) and Professor Carl Gustav Rossby (1957).
‘This is an enormous honour and I am humbled to be named alongside many who I have admired throughout my career,’ comments Professor Palmer.