Heightened interest in the transport and fate of atmospheric pollutants and the impact of turbulent dynamics on large-scale climatic flow patterns have made atmospheric turbulence an increasingly important area of research. Large Eddy Simulation (see computational engineering) has emerged as one of the best ways to model atmospheric turbulence, because the huge Reynolds Numbers in atmospheric flow and the size of the physical domain preclude the use of direct numerical methods.
In Large Eddy Simulation (LES), the equations of motion are solved explicitly for all scales larger than some given threshold (the grid-scale) and motions smaller than these (the sub-grid scale) are parameterized by a set of models that depend on various simplifying assumptions about the small-scale dynamics. Current atmospheric LES suffers from a lack of experimental data on the finer scale physics of atmospheric dynamics. Professors Charles Meneveau and Marc Parlange (of JHU’s Department of Geography and Environmental Engineering) are not comfortable with the assumptions made by many of the current sub-grid scale models.

In a venue far removed from the carefully controlled wind and water tunnel laboratories, Professors Parlange and Meneveau have done several groundbreaking experiments that record turbulent velocity, temperature and humidity data in the atmospheric surface layer over large fields. In a succession of field campaigns in Iowa and California, fine-scale measurements were made over the past three summers using arrays of vertically and horizontally arranged anemometers. This has allowed them to explore properties of the sub-grid scale models, for the first time based directly on field experimental data. In addition, they have developed several new modeling approaches based on the insights gained from these experiments.

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