The 2013 Louis Agassiz Medal is awarded to Florent Dominé for his outstanding contributions to snow and ice physics, including cross-disciplinary studies leading to a fundamental and quantitative understanding of how snow physical properties influence the uptake, retention, and reactivity of chemical species on snow and sea ice.
Florent Dominé has made outstandingly creative, impactful, and timely contributions in the areas of snow and ice physics, chemistry and optical properties, in the context of climate change. He began his career as a geochemist and physical chemist, and this background gave him an intense appreciation for the fundamentals. He has since aggressively applied that orientation to the development of a quantitative understanding of how the physical properties of snow and sea ice influence their interaction with chemical species and the exchange of chemicals between snowpacks or sea ice and the atmosphere. Early on, he published two important and methodologically novel papers on the solubility of two important gases, HCl and HNO3, in ice. These are highly cited papers, reflecting in part the impact on understanding the behaviour of these species in stratospheric ice.
His more recent contribution is his development of methods (using two very different approaches) for measuring the specific surface area of snow. He has applied his methods all over the world, where one can find snow, e.g. in the Alps, all over the Arctic, and in Antarctica. His measurements have enabled him to study snow crystal metamorphism, and how that process influences the exchange of gases with the atmosphere. He has shown that the release of gases into the atmosphere after snowfall can be tied to a change in snow crystal surface area, which impacts a range of processes, including development of the air-snow transfer functions used for inverting ice core data. He has carried out a range of studies of frost flowers, showing that their effective surface area for reaction with atmospheric gases is small, leading to the conclusion (counter to much literature speculation) that they are likely unimportant as surfaces that lead to halogen activation (which leads to ozone and mercury depletion in polar regions). He has been involved in a number of studies of the fluxes of gases from sunlit snowpacks, most significantly, formaldehyde and NOx.
Particularly timely and impressive is his work on development of infrared reflectance for measurement of snow surface area, and relating that to impacts on snowpack albedo. His ability to straddle the worlds of ice physics and atmospheric chemistry has made him a particularly important member of several large polar projects. Given the importance of the cryosphere in the global climate system, it is clear that Dominé’s work will have lasting and significant impact.