Estimation of climatological water deficit in an experimental watershed in the brazilian cerrado

Jackeline T Gotardo,Lineu N Rodrigues,Benedito M Gomes

doi:10.1590/1809-4430-eng.agric.v36n4p631-645/2016

Jackeline T Gotardo, Lineu N Rodrigues + Show 1 more

Open Access

https://doi.org/10.1590/1809-4430-eng.agric.v36n4p631-645/2016

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Abstract

This study aimed to estimate the probability of climatological water deficit in an experimental watershed in the Cerrado biome, located in the central plateau of Brazil. For that, it was used a time series of 31 years (1982–2012). The probable climatological water deficit was calculated by the difference between rainfall and probable reference evapotranspiration, on a decennial scale. The reference evapotranspiration (ET0) was estimated by the standard FAO-56 Penman-Monteith method. To estimate water deficit, it was used gamma distribution, time series of rainfall and reference evapotranspiration. The adherence of the estimated probabilities to the observed data was verified by the Kolmogorov-Smirnov nonparametric test, with significance level (α-0.05), which presented a good adjustment to the distribution models. It was observed a climatological water deficit, in greater or lesser intensity, between the annual decennials 2 and 32.

Highlights

The Cerrado is the main Brazilian agricultural region. It has a climate with two welldefined seasons and the occurrence of water deficit is a major cause of crop losses and low water availability, which puts at risk the agricultural production sustainability in the region
There are several studies in the literature dealing with climatological water deficit (DE LA CASA & OVANDO, 2016; AUTOVINO et al, 2016); few of them take into account its occurrence in terms of probability
SOCCOL et al (2010) estimated probable monthly rainfall for the township of Lages, SC, in Brazil; the results showed that gamma distribution was well adjusted to the data series and in periods without null values in the rainfall decennial time series, it was properly adjusted to the observed data

Summary

Introduction

The Cerrado is the main Brazilian agricultural region. It has a climate with two welldefined seasons and the occurrence of water deficit is a major cause of crop losses and low water availability, which puts at risk the agricultural production sustainability in the region. There are several studies in the literature dealing with climatological water deficit (DE LA CASA & OVANDO, 2016; AUTOVINO et al, 2016); few of them take into account its occurrence in terms of probability. There are several studies on the application of different probability distributions to these variables (YAN & CHEN, 2013; LA CASA & OVANDO, 2016). For irrigation expansion in agriculture in the Brazilian Cerrado, it is interesting to characterize how the climatological water demand behaves. R and ET0 are climatological components with spatiotemporal variability as highlighted by several studies at global level (BOSCHI et al, 2011; LI, 2014)

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