@MastersThesis{Santos:2011:FrEvSe,
author = "Santos, Thalyta Soares dos",
title = "Frequ{\^e}ncia de eventos secos e chuvosos extremos mensais no
Norte e Nordeste do Brasil e suas tend{\^e}ncias no s{\'e}culo
XXI usando SPI",
school = "Instituto Nacional de Pesquisas Espaciais",
year = "2011",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2011-03-10",
keywords = "{\`{\i}}ndice de Precipita{\c{c}}{\~a}o Normalizada (SPI),
Norte, Nordeste, Brasil, tend{\^e}ncias, Standar Precipitation
Index (SPI), North, Northeast, Brazil, trends.",
abstract = "Analisaram-se as frequ{\^e}ncias e tend{\^e}ncias de eventos
secos e chuvosos severos e extremos no Norte e Nordeste do Brasil
no s{\'e}culo passado, usando dados de precipita{\c{c}}{\~a}o
do GPCC (Global Precipitation Climatology Centre) e do modelo
ECHAM5 na rodada 20C e proje{\c{c}}{\~o}es para o s{\'e}culo
XXI deste mesmo modelo em dois cen{\'a}rios distintos, um mais
pessimista (A2) e um intermedi{\'a}rio (A1B). As frequ{\^e}ncias
dos diferentes eventos secos e chuvosos foram obtidas atrav{\'e}s
do {\'{\I}}ndice de Precipita{\c{c}}{\~a}o Normalizada (SPI)
nas escalas 3, 6 e 12 meses. Foi feita uma an{\'a}lise sazonal da
variabilidade espacial das frequ{\^e}ncias e intensidades destes
eventos, assim como as tend{\^e}ncias seculares dos SPIs 3, 6 e
12, para todos os 4 conjuntos de dados. O modelo ECHAM5 n{\~a}o
conseguiu reproduzir bem as precipita{\c{c}}{\~o}es m{\'e}dias
anuais quando comparado {\`a} climatologia das
observa{\c{c}}{\~o}es obtidas pelo GPCC. O vi{\'e}s das
precipita{\c{c}}{\~o}es m{\'e}dias anuais variou de -1 a 1 na
maior parte da regi{\~a}o, e chegou a 4 vezes no Nordeste. As
intensidades m{\'e}dias dos eventos de seca e de chuva foram
inversamente proporcionais a escala de tempo do SPI. As maiores
frequ{\^e}ncias dos eventos severos e extremos de seca e de
chuva, em todos os conjuntos de dados, ocorreram no inverno e na
primavera. A tend{\^e}ncia desses eventos mostrou-se bastante
similar para os SPIs 3, 6 e 12, mas apresentaram diferen{\c{c}}as
entre os dois conjuntos de dados analisados. A d{\'e}cada de 90,
segundo o GPCC, apresentou elevada frequ{\^e}ncia de eventos
severos e extremos de seca, que n{\~a}o foi observada na rodada
20C do ECHAM5. No s{\'e}culo XXI os eventos severos e extremos de
seca e chuva apresentam comportamento similar ao s{\'e}culo XX.
Apesar do cen{\'a}rio A2 ser mais pessimista em
rela{\c{c}}{\~a}o ao A1B, ele apresentou uma menor
frequ{\^e}ncia de eventos severos e extremos de chuva. Ambos os
cen{\'a}rios indicam uma tend{\^e}ncia significativa de
decr{\'e}scimo na ocorr{\^e}ncia dos eventos severos e extremos
em grande parte da regi{\~a}o Amaz{\^o}nica e no litoral do
Nordeste e tend{\^e}ncias positivas no noroeste e sudeste da
Amaz{\^o}nia. ABSTRACT: The frequencies and trends of extreme and
severe dry and wet events in the North and Northeast of Brazil in
the last century were analyzed using monthly precipitation GPCC
data (Global Precipitation Climatology Centre) and ECHAM5 data in
the 20C run. The predictions for the XXI century were made with
ECHAM5 model for two distinct scenarios, an intermediary scenario
(A1B) and one more pessimist (A2). The frequencies of the
different dry and wet events were obtained through the Standard
Precipitation Index (SPI) at the scales of 3, 6 and 12 months. The
seasonal analysis of the spatial variability of the frequencies
and intensities of dry and wet events, as well as its tendencies
through the century, were made for the SPIs 3, 6 and 12, for all
data ensembles. The ECHAM5 model did not reproduced well the
average annual precipitation when compared to the climatology of
observations obtained from the GPCC. The bias of the annual
average precipitation varied from -1 to 1 in the major part of the
region, and reach up to 4 times in the Northeast. The average
intensities of the events of drought and rain was inversely
proportional to the time scale of the SPI. The highest frequencies
of extreme and severe events of drought and rain, in all of the
data set, occurred during winter and spring. The tendency of these
events showed similar for the SPIs 3, 6 and 12, and showed
differences for both ensembles of analyzed data. The 90's decade,
according to the GPCC, presented an anomalous behavior, due to the
high frequencies of extreme and severe drought events, that was
not observed in the 20C run of ECHAM5. In the XXI century the dry
and wet events showed a similar behavior that for the XX century.
In spite of the A2 scenario being more pessimist in comparison
with the A1B, it presented a lower frequency of extreme and severe
rainy events. Both scenarios showed a significant trend of
decrease in the occurrence of extreme and severe events in a great
part of the Amazon region and in the coast of the Northeast
region, and a positive trend in the Northwest and Southeast ofthe
Amazon region.",
committee = "Orsini, Jos{\'e} Antonio Marengo (presidente) and Sansigolo,
Cl{\'o}vis Angeli (orientador) and Mendes, David and Assad,
Eduardo Delgado",
copyholder = "SID/SCD",
englishtitle = "Frequency of monthly extreme dry and wet events in the North and
Northeast of Brazil and theirs trends in the XXI century using
SPI",
language = "pt",
pages = "144",
ibi = "8JMKD3MGP8W/398G9AH",
url = "http://urlib.net/ibi/8JMKD3MGP8W/398G9AH",
targetfile = "publicacao.pdf",
urlaccessdate = "04 maio 2024"
}