Approaches to Multi-Scale Challenges in Measurements and Modeling of Geophysical Flows
Rachel Robey, University of Colorado Boulder
Understanding, measuring, and modeling geophysical flows face common challenges of multiscale turbulence interacting with complex forcing and stratification effects. In this talk, I briefly present findings from research work following two main veins: measurements of the atmospheric boundary layer using remote-sensing instruments and the impact of vertical grid choice in the modeling of ocean dynamics. Wind lidars, which use the scattering of light off of aerosols to diagnose wind speeds, have become widespread and indispensable tools in atmospheric observations. An intrinsic part of lidar measurement error is due to atmospheric variability in the remote-sensing scan volume. I develop and implement a model of the observation system to work in conjunction with large-eddy simulation output, enabling analysis into how measurements interact with complex, realistic atmospheric conditions. Studies of the propagation of error from turbulent variations into profiling lidar measurements of mean winds and potential distortions in the retrieval of wind turbine wakes by scanning lidar are discussed. In my second part of the talk, I address the representation of ocean turbulence and energetics in simulations, focusing on the role of the vertical grid. Mesoscale ocean eddies (10-100 km) play a critical role in the overall earth system, transporting momentum, heat, and key tracers. A grid based on the new coordinate is developed and shown to near optimally resolve the oscillating structure baroclinic modes and nonlinear interactions with a minimal number of layers strategically concentrated in areas of strong stratification. Testing of varying vertical grids is also begun in a simplified, quasi-geostrophic setting. Preliminary results suggest an unexpectedly complex role of the vertical grid in the dynamics with the potential to produce notable deviations in the system energetics.