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| Wax Lake Delta Field Campaign | | In May 2007, NCED researchers went to the Wax Lake Delta in Louisiana. The Wax Lake Delta, small and relatively unaltered in its short history (approximately 35 years), contains an archive of natural delta forms in its depositional systems. Therefore, it represents the best opportunity to explore the creation and stability of coastal lands at distributary mouths of the Mississippi River. Since the delta is the result of interactions between biologic and sedimentologic processes, this group of NCED researchers included ecologists, geologists, and engineers. Data collected from this field campaign includes channel bed topography from a sounding bathometer, vegetated island topography from walking surveys, channel water discharge from a sound profiler, and channel bed composition from bed samples. Although the data has not been fully analyzed, there are some initial findings. For example, the walking surveys reveal that the islands are bounded by levees and have interiors with subtle topography. And, the water discharge measurements indicate that as much as 10% of the total water coming into the Wax Lake Delta could be moving through the very shallow regions that include the vegetated islands. All of the data gathered will ultimately allow researchers to characterize the geomorphology of the area — a necessary first step toward understanding how a delta builds land. To view a poster (pdf) that highlights the Wax Lake Delta field campaign, click here. |  | | Left: Wax Lake Delta, a subsidiary delta of the Mississippi Delta. Right: Researchers having an ecology lesson. | | |
| NCED MYRES 2008 Proposal Wins | | Congratulations to NCED and SAFL postdoctoral research associates who won the 2008 Meeting of Young Researchers in Earth Sciences (MYRES) conference competition. Their proposal, "Dynamic Interactions of Life and its Landscape," which brings together researchers to examine feedback loops between ecology and geomorphology, will be the focus of the MYRES 2008 conference. More information to follow. | | News From the SAFL Wind Tunnel | | NCED PI Fernando Porté-Agel and his research group use the St. Anthony Falls Laboratory (SAFL) wind tunnel to perform experiments focused on understanding the behavior of turbulent boundary layers over homogeneous and heterogeneous surfaces. The information provided by these experiments is guiding the development of improved parameterizations for high-resolution numerical models (large-eddy simulations) of turbulent environmental flows. In particular, a new-generation of tuning-free dynamic models, recently inspired by the experiments, will be implemented in the Virtual StreamLab (DW03) being developed by NCED researchers. A major renovation of the wind tunnel is also currently underway with funding from NASA and NSF. The entire test section floor of the wind tunnel will have water-cooled aluminum plates. The result: Researchers can produce large temperature gradients by heating the air up to 45-50° C while cooling the floor down to about 5° C. Experiments using this new technology will begin in August and will be essential for improving the accuracy of large-eddy simulations of stratified turbulent boundary layers. |  | | Left: Visualization of turbulent boundary layer in SAFL wind tunnel using olive-oil seed particles. Right: Instantaneous velocity magnitude (m/s) from a large-eddy simulation using tuning-free dynamic models. | | | | | |
