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Modeling the Structure of an Arctic Stable Cloudy Boundary Layer Using a Large Eddy Simulation Model |
Department of Meteorology, University of Utah
qzhang@met.utah.edu
An Arctic stable cloudy boundary layer was observed over the SHEBA ice camp on 23 July 1998 during the FIRE Arctic Clouds Experiment. This case provided a good data set for large eddy simulation (LES) research. Herein we perform an analysis of this case using a LES model. The cloud layer was surface based and located in a stable boundary layer below 250 m height, which is characterized by strong wind shear and a pronounced temperature inversion. Our simulations indicate that the LES model is able to provide reasonable mean profiles of the horizontal wind, temperature, humidity and cloud liquid water compared to those observed by aircraft, radiosonde and surface tower.
The budget of turbulent kinetic energy is analyzed based on our LES. Wind shear generates the turbulent kinetic energy within the cloud layer, while the buoyancy and viscous are the dominant energy sink. Sensitivity experiments also suggest that the turbulence of this boundary layer is driven primarily by wind shear.
