Earth, when viewed from space, reveals little earth and much more cloud. Indeed, clouds are an integral part of the earth’s environment: they provide the water we drink, help clean the air we breathe, and influence the climate in which we live. Our research is focused on obtaining a deeper understanding of the physics of clouds, how they form, how they evolve, how they rain, and how they dissipate. Much of this research is conducted in a laboratory, where complex processes in atmospheric clouds are distilled down to their essential elements and studied in a reproducible way. For example, individual cloud or aerosol particles, suspended in an electrodynamic trap, are studied in a controlled environment allowing the detailed physics of the particle-air interface or the spontaneous formation of ice in liquid droplets at low temperatures to be explored.
We also study the influence of small-scale turbulence, which is ubiquitous in the atmosphere, on the formation and growth of cloud particles. For example, we use advanced optical techniques such as digital holography to explore three-dimensional particle clustering in turbulence. In fact, we have even extended the holographic work beyond the laboratory, by flying our instrument, dubbed HOLODEC, on a research aircraft through atmospheric clouds. We study clouds with a broad range of theoretical and experimental tools and the results, we hope, will lead us to a deeper understanding of a crucial part of the Earth system.