In Brazil, there are commonly news of natural disasters as a result of the
occurrence of extreme meteorological events, then it is relevant to study such
phenomena for a better scientific understanding. In this work, the objective is to
analyze the daily precipitation extreme events in Belém-PA during the year 2020.
From the hourly data of the INMET automatic meteorological station, the daily
accumulated was calculated (local time of 1 to 24 hrs) aiming to quantify the
pluviometry covering the periods of dawn, morning, afternoon and night of the
same day. Extreme events were defined as days when daily rainfall exceeded the
threshold of the P97 (64.6 mm) and P99 (90 mm) percentiles. A total of nine
events were identified throughout 2020: 03/Jan, 18/Feb, 07/Mar, 09/Mar, 14/Apr,
17/Apr, 04/May, 21/May and 22/Nov. The analysis of these events showed
precipitation occurring at practically all times, and the average of the nine events
showed some main peaks occurring at dawn (4:00 am), morning (7:00 am),
afternoon (2:00 and 4:00 pm) and night (8:00 and 9 pm). The hourly behavior of
meteorological variables (precipitation, atmospheric pressure, air temperature,
relative humidity and wind speed) was evaluated on the days of extreme events,
and a important result was a sharp decrease of up to 9ºC in air temperature and
an increased wind at the entrance of the extreme event. Finally, 3/3 hour
sequences of GridSAT images from geostationary satellites infrared channel
were used to investigate the meteorological systems observed during the
extreme events. In these analyses, the presence and/or influence of several
synoptic systems was diagnosed, such as the ITCZ, SACZ, Bolivian High, VCAN
positioned in the northeast region and mesoscale systems, such as LI and
Convective Complexes or Agglomerates.
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