VIMHEX 1972 revisited: The life cycles of two tropical convective mesosystems over land

Summary The evolutions of two slow-moving convective mesosystems observed in Venezuela during VIMHEX-II were studied using time changes in radar echo characteristics. The duration of the echo, maximum echo area, maximum echo height and mean echo velocity were about 6 hours, 5000km², 16km, and 95°/5.2m s^–1 for mesosystem A and about 11 hours, 12000km², 14km, and 90°/3.2m s^–1, for mesosystem B, respectively. The rainfall distributions associated with the mesosystems are described and correlated with the radar echo characteristics. The synoptic conditions are discussed, as well as the modification of the environment produced by the mesosystems.The relative wind profiles suggest that mesosystem A behaved more like a typical tropical squall line, with inflow at almost all levels at the front of the mesosystem, while mesosystem B behaved like a typical mid-latitude squall line, with inflow at lower levels and outflow at upper levels at the front of the mesosystem.With 12 Figures