Influence of the Large Scale Systems over the Propagation of the Amazonian Squall Lines

ective line.This work presents a numerical simulation of the formation and evolution of squall lines that are generated in the afternoon along the Atlantic coast and propagate into central Amazonia and of the convective lines that dissipate close to the coast. The literature on Amazonian squall lines points out that low level easterly jets are deeper for these systems and shallower for the systems that dissipate close to the coast. In this work, the focus is on two possible large scale mechanisms that could explain the intensification of the low level easterly jet close to the Atlantic coast: remote convective heat sources and easterly waves. The Regional Atmospheric Modeling System was used to do these numerical simulations. The results of the numerical experiments show that remote heat sources may intensify the low level easterly jet as well as the upper level westerly jet, but the squall line environment is modified in a way not always favorable to the convective line propagation. The easterly waves play an important role in the easterly jet intensification in the northern coast of Brazil providing a deeper easterly jet. Tests with different wind profiles have shown that that without the upper level westerly jet the convective lines do not propagate inland and besides, without the low level and upper level jets the convective line had a short life time defining a coastal conv