SABIIA - Sistema Aberto e Integrado de Informação em Agricultura (Sabiia)

Kruel,Izabele B.; Meschiatti,Monica C.; Blain,Gabriel C.; Ávila,Ana M. H. de.

ABSTRACT Changes in the frequency of occurrence of extreme weather events have been pointed out as a likely impact of global warming. In this context, this study aimed to detect climate change in series of extreme minimum and maximum air temperature of Pelotas, State of Rio Grande do Sul, (1896 - 2011) and its influence on the probability of occurrence of these variables. We used the general extreme value distribution (GEV) in its stationary and non-stationary forms. In the latter case, GEV parameters are variable over time. On the basis of goodness-of-fit tests and of the maximum likelihood method, the GEV model in which the location parameter increases over time presents the best fit of the daily minimum air temperature series. Such result describes a...

Development, yield and quality attributes of sugarcane cultivars fertigated by subsurface drip irrigation

Palavras-chave: General extreme value distribution; Time dependent model; Extreme weather events.

Ano: 2015

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162015000400769

Silva,André L. B. de O.; Pires,Regina C. M.; Ribeiro,Rafael V.; Machado,Eduardo C.; Blain,Gabriel C.; Ohashi,Augusto Y. P..

ABSTRACT The present study aimed to evaluate the development, yield and quality of four sugarcane cultivars fertigated by subsurface drip system. The experiment was carried out in Campinas-SP, Brazil, from January 2012 to November 2013, with the cultivars SP79-1011, IACSP94-2101, IACSP94-2094 and IACSP95-5000 subjected to daily irrigations. The irrigations depths were applied to bring soil moisture to field capacity. Soil moisture was monitored using soil moisture probes. Samples were collected along the crop cycle in order to evaluate crop development and yield, at the end of the first and second ratoons. Stalk height showed good correlation for the estimation of crop yield, with R2 equal to or higher than 0.96. The cultivar IACSP95-5000 showed the...

Dry months in the agricultural region of Ribeirão Preto, state of São Paulo-Brazil: an study based on the extreme value theory

Palavras-chave: Water management; Water déficit; Saccharum spp.; Technological analysis..

Ano: 2016

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016000600525

Blain,Gabriel C..

The application of the Extreme Value Theory (EVT) to model the probability of occurrence of extreme low Standardized Precipitation Index (SPI) values leads to an increase of the knowledge related to the occurrence of extreme dry months. This sort of analysis can be carried out by means of two approaches: the block maxima (BM; associated with the General Extreme Value distribution) and the peaks-over-threshold (POT; associated with the Generalized Pareto distribution). Each of these procedures has its own advantages and drawbacks. Thus, the main goal of this study is to compare the performance of BM and POT in characterizing the probability of occurrence of extreme dry SPI values obtained from the weather station of Ribeirão Preto-SP (1937-2012). According...

Inadequacy of the gamma distribution to calculate the Standardized Precipitation Index

Palavras-chave: Extreme Value distribution; Pareto distribution; Goodness-of-fit tests.

Ano: 2014

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162014000500018

Blain,Gabriel C.; Meschiatti,Monica C..

ABSTRACT The Standardized Precipitation Index was developed as a probability-based index able to monitor rainfall deficit in a standardized or normalized way. Thus, the performance of this drought index is affected by the use of a distribution that does not provide an appropriate fit for the rainfall data. The goal of this study was to evaluate the adjustment of the gamma distribution for the rainfall amounts summed over several time scales (Pelotas, Rio Grande do Sul, Brazil), to assess the goodness-of-fit of alternative distributions to these rainfall series and to evaluate the normality assumption of the Standardized Precipitation Index series calculated from several distributions. Based on the Lilliefors test and on a normality test, it is verified...

Índice padronizado de precipitação aplicado às condições de seca no Estado do Espírito Santo

Palavras-chave: Rainfall departures; Normality test; Goodness-of-fit tests.

Ano: 2015

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662015001201129

Blain,Gabriel C.; Pezzopane,José R. M.; Pezzopane,José E. M.; Bonomo,Robson.

O Índice Padronizado de Precipitação (SPI) é um dos métodos mais utilizados para quantificação da seca. A fim de verificar a possibilidade de utilização do SPI no monitoramento das deficiências e excessos de precipitação na escala mensal, no Estado do Espírito Santo objetivou-se, neste trabalho, verificar o ajuste das séries temporais dessa variável meteorológica à distribuição gama em cinco localidades do Estado. Por meio dos testes de aderência Kolmogorov-Smirnov e qui-quadrado, as séries mensais de precipitação pluvial das localidades sob análise podem ser consideradas oriundas de uma população com distribuição gama incompleta, permitindo o uso do SPI no monitoramento das condições de seca meteorológica. Através de análises de autocorrelação e...

Probabilistic structure of an annual extreme rainfall series of a coastal area of the State of São Paulo, Brazil

Palavras-chave: Distribuição gama; Teste de aderência; Precipitação pluvial.

Ano: 2010

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662010001000007

Blain,Gabriel C.; Camargo,Marcelo B. P. de.

This study aimed to describe the probabilistic structure of the annual series of extreme daily rainfall (Preabs), available from the weather station of Ubatuba, State of São Paulo, Brazil (1935-2009), by using the general distribution of extreme value (GEV). The autocorrelation function, the Mann-Kendall test, and the wavelet analysis were used in order to evaluate the presence of serial correlations, trends, and periodical components. Considering the results obtained using these three statistical methods, it was possible to assume the hypothesis that this temporal series is free from persistence, trends, and periodicals components. Based on quantitative and qualitative adhesion tests, it was found that the GEV may be used in order to quantify the...

Spatial variability of leaf wetness duration in a 'Niagara Rosada' vineyard

Palavras-chave: Extreme values; Adhesion tests; Time series.

Ano: 2012

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162012000300014

Lulu,Jorge; Sentelhas,Paulo C.; Pedro Júnior,Mário J.; Pezzopane,José R. M.; Blain,Gabriel C..

Despite considerable efforts to develop accurate electronic sensors to measure leaf wetness duration (LWD), little attention has been given to studies about how is LWD variability in different positions of the crop canopy. In order to evaluate the influence of 'Niagara Rosada' (Vitis labrusca) grapevine structure on the spatial variability of LWD, the objective of this study was to determine the canopy position of the ÂNiagara RosadaÂ table grape with longer LWD and its correlation with measured standard LWD over turfgrass. LWD was measured in four different canopy positions of the vineyard (sensors deployed at 45Âº with the horizontal): at the top of the plants, with sensors facing southwest and northeast (Top-SW and Top-NE), and at the grape bunches...

Using multi-parameters distributions to assess the probability of occurrence of extreme rainfall data

Palavras-chave: Dew; Rain; Flat plate wetness sensor.

Ano: 2008

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162008000100011

Blain,Gabriel C.; Meschiatti,Monica C..

Soil erosion, soil saturation and floods are frequently associated with extreme rainfall events. Thus, the scientific literature agrees on the need to carry out studies that improve the assessment of the probability of occurrence of extreme rainfall values. The main goal of this study was to compare the performance of the multi-parameters distributions Wakeby, Kappa and Generalized Extreme Value in fitting the annual maximums of daily, 2-day and 3-day rainfall amounts obtained from the weather station of Campinas, located in the State of São Paulo, Brazil (1890-2012). As a secondary aim, the presence of climate trends and serial correlation in these series was also evaluated. The auto-correlation function and the Mann-Kendall tests have shown the presence...

Validação de dados termopluviométricos obtidos via sensoriamento remoto para o Estado de São Paulo

Palavras-chave: Wakeby; Kappa; Climate trend.

Ano: 2014

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662014000300010

Camparotto,Ludmila B.; Blain,Gabriel C.; Giarolla,Angélica; Adami,Marcos; Camargo,Marcelo B. P. de.

Dados termopluviométricos são utilizados em diversos estudos. Contudo, a escassez de dados resultante da baixa densidade de estações meteorológicas é um problema frequentemente encontrado. Com isto, a utilização de dados estimados por satélites tem-se mostrado importante para regiões nas quais eles são escassos. Neste trabalho foram realizadas comparações entre dados mensais de precipitação pluvial estimados pelo satélite TRMM e de temperatura, estimados pelo satélite Aqua/MODIS aos dados observados por estações de superfície, para diferentes localidades do Estado de São Paulo, no período de 2003 a 2010. Os resultados demonstraram que para os dados de precipitação pluvial os menores erros foram observados nos meses de inverno e os maiores nos meses de...