MST radar observations of turbulent altocumulus layers

Abstract

Radar studies of turbulent layers have focused on Kelvin-Helmholtz instabilities caused by vertical shear of horizontal wind, also breaking gravity waves. This study examines another type of turbulent layer, common but rarely studied. Aberystwyth Meso-Strato-Troposphere (MST) radar shows layers of turbulence where there is no unusual wind shear or breaking gravity waves. In three case studies, these layers have a common characteristic of saturated air, reducing the stability to cause possible convective or shear instability. The associated cloud may be already well-known altocumulus. Another case study using the MU radar shows how three-dimensional convective structure can be revealed using a 64-beam method.