Chuva mensal provável para o Agreste de Pernambuco

Abstract

RESUMOO conhecimento da distribuição e da variabilidade temporal da chuva de uma região, é de grande importância, principalmente no Nordeste do Brasil (NEB), na qual este elemento meteorológico é determinante para distinguir dois períodos pluviométricos: o seco e o chuvoso. Desta forma, a chuva exerce grande influência nas atividades agrícolas condicionando a época de plantio e afetando a produtividade dos cultivos. No presente trabalho foram analisadas as distribuições de probabilidade experimental e teórica, aplicadas a uma amostra de dados de chuva mensal do município de Pesqueira, situado no NEB, Agreste pernambucano, obtida da série histórica de 1920 a 2010. Para verificar a aderência das probabilidades estimadas às frequências observadas aplicou-se o teste não-paramétrico Qui-quadrado. Como período chuvoso identificaram-se os meses de fevereiro a julho, com média de 84,6 mm mês -1 e, como período seco, de agosto a janeiro, com média de 46,0 mm mês -1 . A distribuição Normal foi a que melhor se ajustou ao período chuvoso representando 50% dos meses analisados.Palavras-chave: função densidade de probabilidade, semiárido, testes não-paramétricos Probable monthly rainfall in the 'Agreste' of Pernambuco State ABSTRACT Rainfall distribution and its temporal variability are relevant characteristics, mainly in the Northeast of Brazil (NEB), where rainfall is a key factor which determines the two seasons in the region: the dry season and the rainy season. Thus, rainfall has a strong influence on the agricultural activities, determining the cropping periods and affecting the crop development and harvesting. In the present work, four probability distributions for monthly time series of rainfall were analyzed for the Pesqueira town in the 'Agreste' region of Pernambuco, situated in the NEB, from 1920 to 2010. To verify the fitting of the probability functions to the observed frequency, non-parametric chi-squared test was applied. For the rainy season, the period from February to July, was characterized with a mean rainfall of 84.60 mm month -1 ; the period from August to January was identified as the dry period presenting a mean precipitation of 46.0 mm month -1 . The Normal distribution presented the best fit for the rainy period records, representing 50% of the analyzed months.

Probability of occurrence of water deficits and excess on the climatic conditions of Barreiras, Bahia

“…The standard deviation varied from a minimum value of 2.7 mm in July to a maximum of 108.6 mm in January. The major values of standard deviation occurs in the rainy period, and that same kind of behavior was verified by SILVA et al (2013b) in the study of the probable rain for the Agreste of Pernambuco, in the rainy period it was observed the major values of standard deviation, indicating great variation on the values of rain in a same month of the year. This way, from the statistical point of view, the fluctuations on the rain values is a sign that the adoption of the monthly average rain for the agricultural planning is not effective in the region.…”

“…The Normal distribution adjusted to the monthly precipitation in the humid period in Táchira, Venezuela, with the application of the adherence test χ 2 at 5% of significance (LYRA et al, 2006). In the climate conditions of Pesqueira in the Agreste of Pernambuco, through the application of the adherence test χ 2 at 5% of significance, the Normal distribution adjusted to the rain data in the months of May, June and August (SILVA et al, 2013b).…”

Modelagem da dinâmica de umidade do solo em diferentes condições de cobertura no semiárido pernambucano

“…déficit hídrico. Conforme Silva et al (2013), a precipitação média da região é de 671,90 mm. Em 2013, a precipitação acumulada foi de 320,30 mm e a evapotranspiração potencial de 930,60 mm até o dia 31 de maio, enquanto que no ano de 2012 o total para o mesmo período foi de 895,90 mm.…”

Coupling Water Resources and Agricultural Practices for Sorghum in a Semiarid Environment

“…Pernambuco State (Brazil) semiarid was classified as one of the driest zones, with an accumulated annual rainfall of 571 mm. The occurrence probability of monthly rainfall distribution in Pesqueira municipality (Pernambuco State; the same region adopted in this study), based on an observed time series from 1920 to 2010 [35]. The mean rainfall from February to July was 84.60 mm month −1 (hydrological year in the region).…”