Characteristics of Thermally-Induced Near-Surface Flows over An Enclosed Crater: Observations of the Meteor Crater Experiment (Metcrax)

摘要

Meteorological measurements of the Meteor Crater Experiment (METCRAX) were used to analyze the characteristics of the thermally-induced flows over an enclosed crater (Arizona, USA). Despite its relatively small size, this crater acts as an effective wind shelter. Daytime upslope winds and nocturnal downslope flows are regularly observed on its west/east sidewalls. The times of diurnal wind-direction shift (i.e., around sunrise and sunset) were slightly mismatched between the sites based on the east and west sidewalls, owing to the crater’s shadowing effects. Under conditions of relatively weak synoptic forcing, the nocturnal downslope flows prevail throughout the night, despite quite a low wind velocity near the surface.