Structure and horizontal distribution of thermal updraughts in a cloudless boundary layer in southern Bavaria

Abstract

A case study of the structure and horizontal distribution of thermal updraughts is presented for a fully convective, but cloudless, boundary layer with moderate mean winds using time series analysis techniques...  The typical spacing between weak updraughts (1-2 m/s) is about 3 km and between strong updraughts (5 m/s) about 17 km....  Spectral analysis indicates a horizontal length-scale of the strongest updraught regions of about 1.3 km whereas broader updraught systems and induced convective waves contribute most to the mean downward momentum flux at wavelengths of about 4 km.