@InProceedings{SouzaPalMirSouNas:2018:RaTyFl,
author = "Souza, Diego Oliveira de and Palharini, Rayana Santos Ara{\'u}jo
and Miranda, Gustavo Santos Barbosa and Souza, Pedro Henrique Melo
de and Nascimento, Marilia Guedes do",
affiliation = "{} and {Instituto Nacional de Pesquisas Espaciais (INPE)} and {}
and {Instituto Nacional de Pesquisas Espaciais (INPE)} and
{Instituto Nacional de Pesquisas Espaciais (INPE)}",
title = "Rain type and flood events in southern of Brazil",
booktitle = "Proceedings...",
year = "2018",
organization = "American Meteorological Society (AMS), 98.",
abstract = "In Brazil there is more than 12,000 flood and flash flood events
already registered (1991-2012) (CEPED, 2013), with a total number
of impacted people by such events exceeding 20 million. The
Southern and Southeastern regions of Brazil together account 69%
and 56% of floods and flash floods occurrences, respectively, with
events throughout the year, but more frequently during the summer
period of the Southern Hemisphere. The main phenomena related to
flood events usually occur associated with intense and prolonged
rainfall events in the rainy periods, which correspond to the
summer in the South and Southeast regions and the winter in the
Northeast Region. In Brazil, a large part of the scientific
community associates natural disasters to meteorological systems,
but there is still a gap in the knowledge of the relationship
between rainfall type and flood events. In addition, results
regarding these relationships may bring improvements in the
representation of rainfall in meteorological models, especially
for short periods of time, thus producing subsidy for more
effective warnings for natural disasters related to precipitation.
In this context, the objective of this work is to identify
patterns of rainfall and main atmospheric characteristics,
directly related to the occurrence of floods in some states of
southern of Brazil, where initially were cataloged 444 flood
events. In order to determine the type of rainfall for each
occurrence of cataloged flood, the product 2A25/PR-V7 obtained by
the radar on the Tropical Rainfall Measuring Mission (TRMM)
satellite was used, and for identify the meteorological systems
and atmospheric patterns associated with flood events analyzed, we
used data from the Modern Era Retrospective Analysis for Research
and Applications (MERRA). Considering the proposed methodology,
192 events were recorded for the study. Seasonally, 61% of the
events occurred during the summer, 12% during autumn, 11% during
winter, and 16% in the spring. The results allowed to observe that
of all the analyzed events there is predominance of stratiform
rainfall, followed by shallow convective and deep convective
rainfall. It is noted that the frequency of occurrence of rainfall
types for the events analyzed in the states is shown according to
the climatology. When analyzed the rainfall rate for each type of
rainfall, it is observed that for the events occurred in the north
of the study area, the highest rates are related to deep
convective rainfall, while for the south part of the study area
the stratiform rainfall events are those that present higher rates
for the studied events. When analyzing the spatial distribution of
the rain type, it is observed that a great part of the events of
stratiform rain are concentrated in the east part of continent,
and nucleus on the coast and another one in the extreme west. The
events of deep convective rainfall are more frequent on the north
part, especially on the northwest, whereas the events of shallow
convective rainfall are well distributed over the study area, with
low frequency in the south part. The precipitation rate
characteristics for each type of rain show to be directly related
to the type of meteorological system that is active in the study
area, where for the south a large part of the events (86%) are
related to the frontal systems and, for the north, a large part of
the events (63%) are related to the South American Convergence
Zone (SACZ). The geopotential and flow anomalies show that on the
surface there is an intensification of a low pressure system and a
displacement of an anomalous cyclonic flow towards the south of
Brazil during the flood events, supporting the condition of
frontal and SACZ. The predominant occurrence of stratiform
rainfall during flood events in the south part of the study area
may also have a direct relation of the interaction between
transient systems, observed in flow and geopotential anomalies,
and orography. On the north part of the study area, the anomalous
conditions of circulation and geopotential support the performance
of the SACZ and the convective activity associated to this system,
having a direct relationship with the found results. Finally, the
results obtained will provide subsidy for the monitoring of flood
events from remote sensing, and contributing significantly to the
improvement in precipitation parameterization schemes in
meteorological models for weather forecasting and nowcasting.",
conference-location = "Austin, Texas",
conference-year = "6-11 jan.",
label = "lattes: 2887110604837386 2 SouzaPalMIRSOUNAS:2018:RaTyFl",
language = "en",
url = "https://ams.confex.com/ams/98Annual/webprogram/Paper334027.html",
urlaccessdate = "28 abr. 2024"
}