Análise de padrões temporais da dinâmica do vento associadas ao ambiente de formação das linhas de instabilidade amazônica.

Abstract

The aim of this work is to contribute to the understanding the mechanisms responsible for the formation of Amazon Tropical Squall Lines (ASL). 3 years of reanalysis data were analyzed investigating the dynamic characteristics of vertical profiles of the zonal and meridional wind from the a average of period and quarterly of the days with and without the ASL formation. It has been shown that low level jet (LLJ) is an intrinsic characteristic of Amazonian environment, however in the days with the formation of SL this LLJ is more intense and deep. The quarters March-April-May and June-July-August do not present a well defined LLJ, mainly in relation their depth. It was also pointed out that vertical shear of wind is more intense on days with ASL formation. However, the greatest directional shear of meridional component wind is seen in the profiles of days without ASL. To aid the understanding of temporal variability of vertical profiles wind were applied the method Principal Components Fatorial Analysis in order to investigate the existence of atmospheric patterns associated with the occurrence of ASL. The first three Principal Components of the zonal wind component explained approximately 89% of the total variance of the data, while the 89% of the total variance of the meridional wind component were explained by the first five principal components. The analysis of the time patterns associated with each factor suggests that the DJF and SON quarters are influenced by the seasonal variation of the ITCZ and the quarters MAM and JJA by South Atlantic Subtropical High (SASH) and Easterly Wave Disturbances (EWD).