Analysis of meteorological variables interaction associated with the environment of formation of Amazonian squall lines.

Abstract

The relationships among humidity, air temperature, wind, and vertical velocity with formation and propagation of Amazonian squall lines (ASL) is analyzed in this study. One year of data (2005) is verified by counting ASL cases according to their classification (propagated and non-propagated) to understand more clearly how the variation of these variables over this year influences their environment of formation. The results show an increase in humidity on days with ASL, with the highest occurrence during the wettest months. Furthermore, system propagation toward the interior of continent seems to be strongly related to the moisture content that reaches the coast, through the winds that blow from the ocean from both by the Northeast Trade Winds, of the North Atlantic Subtropical High, and by the Southeast Trade Winds, of the South Atlantic Subtropical High. Higher moisture content from the sea corresponds to a higher wind intensity toward the coast. A relationship between continent/ocean temperature gradient and the ASL amount and types formed is also demonstrated. Such information is extremely relevant because of the great importance of these systems in the extreme north and northeast regions of Brazil, particularly at the Amazon, given the difficulty of predicting them due to their complexity.