II SIC – SIMPÓSIO INTERNACIONAL DE CLIMATOLOGIA DA SBMET
2 E 3 DE NOVEMBRO DE 2007 – SÃO PAULO/SP - BRASIL
THE TREND OF PRECIPITATION IN THE NORTHEAST REGION OF BRAZIL
Jonas Teixeira Nery and Ana Claudia Carfan
UNESP/Ourinhos
[email protected], [email protected]
ABSTRACT
The purpose this paper is to analyze a spatial and temporal from rainfall variability in the
Northeast region of the Brazil. It was analyzed 23 dataset rainfall for the period of 1913 to
2005. Tendency was calculated for the periods and also tendencies for periods of 31 years.
This area presented variability in different temporal scales.
Keywords: rainfall, variability, Northeast region
SUMMARY
The purpose of this work r is to analyze a spatial and time interval of rainfall variability in the
Northeast region of Brazil. An amount of 109 series of annual and monthly data rain
precipitation within the period of 1990 to 2005. The statistic software was used to identify six
homogeneous regions of pluviometrical regime.
According to Lima (1991) , the Northeast of Brazil is submitted to the influence of
meteorological systems , due to its localization in the extreme east of South America,
conferring to it differentiated climatic characteristic. These systems are: Upper Bolivia,
Subtropical upper South Pacific, North Atlantic and South Atlantic, Intertropical Zone
Convergence , among others.
Uvo , C.R.B (1989) analyzed the influence of the dislocation of Atlantic Convergence Zone
(ZCIT) on the precipitation in the North region, Northeast of Brazil, verifying that ZCIT
defines the quality of the rainy period in the region.This work used 23 rainfall periods,
obtained from the “Hidroweb” site, of National water Agency (ANA). It was calculated the
inclination for the total annual of the period and for three series of 31 years: 1913 to 1943,
1944, 1974, 1975 to 2005.
In 2005 it was analyzed precipitations for the year of 1913, for the humid period (November
to March) and for the dry period ( May to September).
For the first 31 years all the periods had presented negative inclination for this period, a
precipitation reduction.
For the period of 1944 to 1974 the majority of the periods presented reversion with
significant values, that’s why had occurred higher indexes of rain in the period, when
comparing to the previous period. The last 31 years had presented variability in the trend,
with positive and negative values in all the area.
It was observed a major precipitation index for the first months. The precipitation regimen in
the Northeast region has been modified throughout the time. In the analysis of the pluvial
precipitation, a reduction in the years of 1913 was observed in 1943. On the other hand the
years of 1944 to 1974 presented a growth in the precipitation in all the studied area. For the
last years a variability finds space , in some periods with positive trend next to the coast and
others with negative trend situated in the interior of the continent.
It was observed higher indices of precipitation during the first months of the year (summer)
with a heavy diminishment in the months of June , July and August (Winter), station 89
II SIC – SIMPÓSIO INTERNACIONAL DE CLIMATOLOGIA DA SBMET
2 E 3 DE NOVEMBRO DE 2007 – SÃO PAULO/SP - BRASIL
(North of the area) was the one which presented the highest values of precipitation in the
summer, and the lowest values in the winter.
It was also observed great precipitation indices in the summer, mainly in the months of
February, March and April. In the winter the precipitation was almost null. Except the 108
station located more to the south of Northeast.
The same standard for the first 62 years was observed in the last 31 years , with the highest
precipitation in the summer.
BIBLIOGRAPHY
BATISTA DA SILVA, J. et al. Análise do Comportamento das Chuvas em Algumas
Localidades do Semi-árido do Nordeste Brasileiro. Santa Maria: Revista Brasileira de
Agrometeorologia V13, n٥1, 2005. p. 173-181.
LIMA, M.C. de. Variabilidade da Precipitação no Litoral Leste da Região Nordeste do Brasil.
São José dos Campos – SP : INPE-5283-TDI/453, 1991. 222 p.
UVO, C.B. A Zona de Convergência Intertropical (ZCIT) e sua relação com a precipitação da
Região Norte do Nordeste Brasileiro. São José dos Campos – SP: Dissertação de
Mestrado 1989. INPE-4887-TDL/378. 81 p.
GIRARDI, C.; Teixeira, L.. Prognóstico de Período de Seca para o Nordeste Brasileiro. São
Jose dos Campos SP: CTA/IAE, 1978. 60 p.