Medal Awards #3
Thursday, 16 April 2009
Christopher A. Jones to receive Petrus Peregrinus Medal at EGU 2009

Christopher A. Jones is a professor in applied mathematics at the University of Leeds. His specialisation is magnetic field generation in the earth, as well as in other planets. To understand the “geodynamo”, scientists build computer models to simulate processes in the inner earth, such as convection. It is the motion of fluid rock around the solid iron core that generates the magnetic field. Jones contributed greatly to this kind of modelling by demonstrating the importance of electrical conductivity in the inner core. This property makes the earth's magnetic field more stable and explains why geomagnetic reversals, the shifting of the magnetic poles, occur only on long geological time scales. Professor Jones also solved a persisting mathematical problem regarding the onset of convection in rotating spheres. In his medal lecture at the General Assembly, he will give an overview of the significant advancements that have been made in the field of earth magnetism over the past fifteen years. Nowadays, the most powerful computer models are able to accurately display the characteristics of the earth's magnetic field, extending thousands of kilometres into space. They can even reproduce field reversal events. At the EGU 2009, Christopher A. Jones will receive the Petrus Peregrinus Medal.

Eigil Friis Christensen to receive Petrus Peregrinus Medal at EGU 2009

Eigil Friis Christensen is the director of the Danish National Space Center in Copenhagen. In his career, he made some fundamental contributions to the observation of the earth's magnetic field. While employed at the Danish Meteorological Institute, he conducted research based on the establishment of the Greenland Magnetometer Array, a network of 17 geomagnetic instruments spread across the island. This facility is now internationally regarded as a highly valuable research tool. In 1999, Christensen was closely involved in the launch of the first Danish satellite, the Ørsted, which measures magnetic and gravity field variation. Its sensitivity allows it to even observe changes caused by oceanic tides. Christensen will discuss the succes of the Ørsted and other geomagnetic observation missions in his medal lecture at the EGU General Assembly. He will also give attention to the multi-satellite mission “Swarm”, to be launched in 2010, aimed to provide the best ever survey of the earth’s geomagnetic field and its changes. At the EGU 2009, Eigil Friis Christensen will receive the Petrus Peregrinus Medal.

Models and reconstructions in climate change: Pascale Braconnot to receive Milankovitch Medal

Small variations in the orbit of the earth and the rotation of the earth's axis continuously change the amount of solar radiation that reaches the earth. This theory, published in 1920 by Milutin Milankovitch, is nowadays one of the most famous in climate science. It explains long-term climate changes such as ice ages. Pascale Brannocot is one of many scientists who presently applies the theory of Milankovitch to better understand the earth's climate. She is for example interested in the influence of solar irradiance on the Indian and African monsoons, and on the strength of El Niño. Braconnot is also involved in the Paleoclimate Modelling Intercomparison Project (PMIP), in which the output of different climate models is compared between each other and to data from climate reconstructions. For some time periods, it shows, model results are still quite inconsistent. In the organisation of PMIP, Braconnot fostered the relationships between the modelling and climate reconstruction communities, which led her to act as lead author of the chapter "Understanding and Attributing Climate Change", in the last IPCC report. In her medal lecture, Braconnot will show the importance of the analyses of past climates, to help us understand how the climate reacts to changes in solar irradiance. At the EGU 2009, Pascale Braconnot will receive the Milutin Milankovitch Medal.

The physics of mountain creation: Stefan M. Schmid to receive Stephan Mueller Medal

The formation of the Alps is a complex geological process that still isn't fully understood. Several tectonic plates have been pressed into each other, folding together to form a rough mountain range. Modern techniques allow geologists to examine the internal structure of mountains, showing how they formed. Stefan Schmid has achieved great success with geophysical deep sounding of the alps. With this technique, electromagnetic and shock waves are sent into the ground, and their reflections are recorded. The transition from one rock type into another causes the waves to refract. Otherwise hidden information about the anatomy of a mountain range is now revealed. Combined with modern fieldwork, Schmid developed detailed cross sections of the Alps. As he will show in his Medal Lecture at the EGU General Assembly, their formation was far more complex than hitherto believed. Schmid has also lent his experience to applied geology, specifically relating to railway tunnel construction in the Alps and earthquake risk assessment in the upper Rhine Graben area. Stefan M. Schmid will receive Stephan Mueller Medal at the EGU 2009.

Rainfall and runoff: Jeffrey J. McDonnell to receive John Dalton Medal


Jeff McDonnell holds the Richardson Chair in Watershed Science at Oregon State University. He is a hydrologist with great experience in runoff processes. In other words, McDonnell is occupied with the question: “where does water go when it rains?” The basic principle of this issue is simple: Rain water either flows on the surface to the stream, or it infiltrates into the soil where it is transported much slower. The exact amounts, timespan and pathways are very difficult to determine, however. McDonnell conducted field research in watersheds all over the world, and integrated this data into computer simulations. He has led the hydrological community towards a paradigm shift in hydrological thinking by arguing that storm water in the stream, despite its rapid response to storm rainfall, is composed largely of water stored in the catchment prior to the event. From 2005 to 2007, McDonnell chaired a research programme called PUB: Prediction in Ungauged Basins. The PUB programme is focussed on predicting runoff in data-scarce environments. McDonnel will discuss practical approaches to engage in this challenging research in his Medal Lecture. At the EGU 2009, Jeffrey J. McDonnell will receive the John Dalton Medal.