The objectives of this research are: (1) the investigation of the physics of downbursts, particularly the structure and evolution of water substance in convective clouds and the resulting formation and development of downdrafts, (2) the wind and thermal structure of the turbulent convective boundary layer as observed by doppler radar, (3) the theory and practice of computing air motions using doppler radars and (4) conducting a field experiment (near Champaign, Illinois) using a doppler radar, the Flatland radar, and additional surface and radiosonde stations to investigate the structure and evolution of winter fronts. //