CYCLONE TRACK ANALYSIS BASED ON 10 YEARS OF SYNOPTIC CHARTS FOR THE
SOUTHWESTERN ATLANTIC (METAREA V)
Abstract
Extratropical cyclones are weather phenomena with significant transfer
of energy between the surface (over the ocean or on land) and the
atmosphere. Recurrently, reanalysis data are used to understand the
behavior of cyclonic tracks and to study extreme events, with constant
updates and validations with the observational base in the Northern
Hemisphere. However, studies using cyclone tracking in the Southwestern
Atlantic, has proven more difficult. This disagreement seems to be in
function of the structure and intensity of the forcing factors that
influence both cyclogenesis and the displacement to the South Atlantic,
when compared to the Northern Hemisphere. In this work, synoptic
pressure charts at sea level, manually made and processed by the
Brazilian Navy every 12 hours between the years 2010 and 2020, as a
product resulting from a consensus among Navy meteorologists, were used
to study the cyclonic pathways in the Southwestern Atlantic (METAREA V).
Data obtained for all cyclones identified in the charts, based on their
position and displacement, formed a database with 10737 cyclones,
containing speed, dimensions, and pressure gradient. The cyclones
identified have a higher radius frequency between 200/400 km and a
faster-moving center shift. In addition, about 60% of cyclones
associated with cold fronts have a life cycle ranging from 3 to 4 days.
There is also a expressive cyclogenesis between latitudes 23ºS and 43ºS
where, in austral autumn winter, increases its frequency over the ocean
and close to the southern Brazilian coast. During spring, the greater
cyclogenesis frequency occurs over the continent, close to Chaco area in
Argentina and Uruguay. The impacts of these statistical figures on the
south and southeastern Brazilian coast, mainly the continental insertion
point of the cold fronts and cyclonic displacement that influence rough
seas and storm surges, are discussed in this work. Keywords:
EXTRATROPICAL CYCLONES, CYCLONE TRACK, SYNOPTIC CHARTS, SOUTHWESTERN
ATLANTIC