A numerical study of turbulence structure inside a small basin

We present an investigation into the turbulent atmosphere inside Arizona's meteorite crater (1200 m in diameter and 160 m deep) under the framework of The Meteor Crater Experiment (METCRAX). Previous observations of wind velocities using sonic anemometers inside and outside the crater, during near neutral atmospheric conditions with wind speeds greater than 10 m/s revealed a very turbulent crater interior, with turbulent kinetic energy (TKE) reaching 3 times the measured value outside and upwind of the crater. The objective of this work is to simulate a similar condition during the observed high TKE regime with the intention of verifying the performance of the Advanced Regional Prediction System (ARPS) model in resolving such a micro-scale phenomenon and depicting TKE differences inside and outside the crater. The ARPS-model was setup in 3D-LES mode with an initial step velocity profile of 10 m/s, an isotropic grid resolution of 10 m, a forced neutral vertical temperature profile, and with the exclusion of the surface heat budget modeling. Preliminary results from multiple sensitivity experiments of model parameter tuning and the crater rim and no-rim case showed the capability of the ARPS-model to operate successfully at this scale and revealed physical turbulent features inside and in the wake of the crater. Further analysis will include deriving the turbulence spectrum and TKE spatio-temporal evolution and compare with observed profiles. This work provides a specific investigation of the capability of the ARPS-model in resolving micro-scale turbulence with a focus on a closed-basin environment.