The 2012 Vilhelm Bjerknes Medal is awarded to Adrian Simmons in recognition of his outstanding and diverse scientific contributions to dynamic meteorology and numerical weather prediction over the past four decades.
Adrian Simmons has played a pioneering role in the development of dynamical meteorology and numerical weather prediction over the past four decades. His achievements provide an outstanding example of how theoretical insight and analytical skills can be used with great advantage to further practical applications in the field of meteorology. He is a most worthy recipient of the Vilhelm Bjerknes Medal. Simmons began his career at the University of Cambridge with dynamical studies of planetary-scale disturbances in the stratosphere, including instabilities and forced motions. His outstanding analytical skills were clearly demonstrated in these early studies. He then worked at the University of Reading on the development of the spectral atmospheric model and used this model to carry out fundamental studies of linear and non-linear baroclinic instability on the sphere. His studies of the life cycles of non-linear baroclinic waves and of the downstream and upstream development of unstable waves were fundamental contributions to dynamic meteorology. On the establishment of ECMWF, Simmons took up a position there and for the rest of his career worked in a mission-oriented environment. Through his research and development work, he contributed in a crucial way to the great success of ECMWF. His work on various aspects of numerical modeling, including comparisons of spectral and finite difference simulations, the development of energy and angular momentum conserving vertical finite difference schemes, the use of hybrid coordinates, the treatment of orography, the study of error growth and predictability, developments of the semi-implicit method and reduced Gaussian grids in spectral models were of universal interest in the field of atmospheric modeling. Simmons has also played an important role in the development of data assimilation methods and in the production of the reanalysis products at ECMWF, which are of great benefit to the world meteorological community and of increasing use in climate research. He continues to do work of international significance in the development of global environment monitoring.