Structure and Dynamics of a Tropical Squall–Line System

Abstract

Abstract A tropical squall-line system which moved over the observational network of the Global Atmospheric Research Programme's Atlantic Tropical Experiment (GATE) was investigated using rawinsonde, weather radar, satellite, surface meteorological, acoustic sounder and cloud photographic data. Combining these data led to a detailed synthesis of the three-dimensional structure, dynamics and life cycle of the disturbance. The squall-line system consisted of a squall line forming the leading edge of the system and a trailing anvil cloud region. The squall line was made up of discrete active centers of cumulonimbus convection, referred to as line elements (LE's). New LE's formed ahead of the squall line. Old LE's weekened toward the rear of the line and blended into the trailing anvil region as they dissipated. Each LE progressed through a period of rapid growth, with echo tops penetrating the tropopause to maximum heights of 16–17 km, then decreasing to heights of 13–14 km, which corresponds to the height o...