@InProceedings{BrescianiBoiaFerrHerd:2022:SoAtCo,
author = "Bresciani, Caroline and Boiaski, Nathalie Tissot and Ferraz,
Simone Teleginski and Herdies, Dirceu Lu{\'{\i}}s",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and
{Universidade Federal de Santa Maria (UFSM)} and {Universidade
Federal de Santa Maria (UFSM)} and {Instituto Nacional de
Pesquisas Espaciais (INPE)}",
title = "The South Atlantic Convergence Zone Represented by BAM Model
Simulations",
year = "2022",
organization = "American Meteorological Society Annual Meeting, 102.",
publisher = "AMS",
abstract = "The South Atlantic Convergence Zone (SACZ) has been subjectively
defined as a band of cloudiness from the intense convection over
the Amazon basin extending toward southeast Brazil, that is one of
the main components of the South American monsoon system. The SACZ
represents a region of deep convection, causing heavy
precipitation events in the region for at least 4 days. The
precipitation that occurs during the months of October to March is
essential for maintaining the climate of the Southeast, Midwest
and North of Brazil. Because of this, SACZ is an important
climatological feature of the austral summer in Brazil. Its
non-occurrence can cause problems of water scarcity, decrease of
the water reservoirs and in the energy supply. On the other hand,
the occurrence of excessive SACZ events are also harmful to
society and economy. Extreme precipitation events associated with
SACZ have been known by the population for decades, due to records
of floods, cuts in energy supply, for example. During the same
period, two other systems act simultaneously in the South America,
at the 200hPa level, a high pressure system over the Bolivian, the
Bolivian High and a cyclonic vortex over the Northeast Region of
Brazil. Therefore, the representation of SACZ precipitation is
very complex and the need for numerical models calibrated
according to the atmospheric conditions of the region to be
analyzed is increasing. Thinking on this, researchers from the
National Institute for Space Research (INPE) have been developing
the Brazilian Global Atmospheric Model (BAM), that is the
atmosphere component of the Brazilian Earth System Model (BESM) in
order to improve weather and climate forecasting simulations and
climate change studies. The BAM is a semi-implicit Eulerian
spectral model (BAMb-SL version) with approximately 1.0° x 1.0° of
horizontal resolution. The model has been improved by researchers
and students from Brazilian institutions who assist in the
analysis of BAM simulations, and thus adapt the necessary
parameters to improve the simulations of atmospheric systems
operating in Brazil. With the importance of SACZ in mind and the
need to improve its prediction, this study aims to analyze the
climatology of SACZ through simulations of the BAM model in the
period between 1992 to 2015, in which 56 SACZ event were recorded.
BAM simulations will be compared with observed and reanalysis
data, in order to evaluate the performance of BAM simulating ZCAS.
The data that will used in this study is the BAM simulations of
the variables precipitation, 200-hPa wind, outgoing longwave
radiation, and 850-hPa specific humidity, daily observed
precipitation data of Brazil from the National Institute of
Meteorology (INMET), the National Water Agency (ANA) and the
Department of Water and Electric Energy of S{\~a}o Paulo (DAEE),
interpolated in high spatial resolution (0.25° x 0.25°), outgoing
longwave radiation from Climate Prediction Center do National
Oceanic and Atmospheric Administration (CPC NOAA) and 200-hPa wind
and specific humidity at the level of 850-hPa from ERA-Interim of
the European Centre for Medium-Range Weather Forecasts (ECMWF)
reanalysis. The analyzes were obtained from statistical methods,
with the mean and monthly standard deviation of the accumulated
precipitation, and mean monthly of the outgoing longwave
radiation, 200-hPa wind and specific humidity at the level of
850hPa, applied which data sets that were explained. Overall, the
initial results showed a good agreement between the two sets. The
average precipitation accumulated in the 56 SACZ events recorded
by the observed data were between 64-100 mm/event in central of
Brazil, with the maximum values were observed in the northern
region of the country. The average accumulated precipitation
presented by the model simulations represented the spatial
distribution of precipitation, the precipitation maximums
(40-80mm/event) in the central region of the Brazil were
characterizing the SACZ, but these values were lower compared to
those observed. The lowest OLR values presented by the reanalyses
on the central region of the Brazil characterizes the SACZ
position, with values between 185 and 217 W/mē, whereas the
simulations was an minimum of 243 W/mē in the central region of
Brazil. The other variables are still being analyzed. With the
results obtained untill now, it is possible to say that, although
the magnitude of each variable is underestimated, the simulations
showed a good level of agreement between the data sets in the
spatial representation of the variables analyzed in the 56 SACZ
events.",
conference-location = "Houston, Texas",
conference-year = "23-27 jan. 2022",
language = "en",
ibi = "QABCDSTQQW/468R6KS",
url = "http://urlib.net/ibi/QABCDSTQQW/468R6KS",
targetfile = "EGU22-4723-print.pdf",
urlaccessdate = "25 jun. 2024"
}