Stationarity of Mesoscale Airflow in Mountainous Terrain

Abstract

Criteria for stationarity of turbulent atmospheric flow are examined for the mesoscale in a mountain valley in northeastern Utah. Data from four sequences of superpressure balloon flights are used. The study shows that the horizontal components of the Lagrangian velocities at levels below the ridges of the surrounding mountains are only weakly stationary; the vertical component fits the criteria better. Above the ridge levels all components of the velocities exhibit reasonable stationarity in the turbulent flow.