Abstract
Eastern Northeast Brazil (ENEB) generally experiences a high variability in precipitation in the dry season, with amplitudes that can overcome 500 mm. The understanding of this variability can help in mitigating the socio-economic issues related to the planning and management of water resources this region, which is highly vulnerable to drought. This work aims to assess spatio-temporal variability of precipitation during the dry season and investigate the relationships between climate phenomena and drought events in the ENEB, using univariate (Spearman correlation) and multivariate statistical techniques, such as Principal Component Analysis, Cluster Analysis and Maximum Covariance Analysis. The results indicate that the variability of precipitation in the dry season can be explained mainly (62%) by local physical conditions and climate conditions have a secondary contribution. Further analysis of the larger anomalous events suggests that the state of Atlantic and Pacific oceans can govern the occurrence of those events, and the conditions of Atlantic Ocean can be considered a potential modulator of anomalous phenomena of precipitation in ENEB.
Highlights
Understanding climate variability is essential to the better quantification of processes related to hydrological cycle in order to improve long-term forecasting of extreme events such as droughts (Silverman and Dracup, 2000; Morid et al, 2007; Labat, 2010; Massei and Fournier, 2012; Räsänen and Kummu, 2013)
Considering the drought events that affected more than 70% of the area, only four events were observed for both Homogeneous Groups
The two Homogeneous Groups defined by Cluster Analysis were closely related to the first and second PCA modes
Summary
Understanding climate variability is essential to the better quantification of processes related to hydrological cycle in order to improve long-term forecasting of extreme events such as droughts (Silverman and Dracup, 2000; Morid et al, 2007; Labat, 2010; Massei and Fournier, 2012; Räsänen and Kummu, 2013). Major efforts have been made in the last decade to understand the dynamics of intensity and frequency of droughts, either by using teleconnection concepts to find relations between climate and drought indices (Morid et al, 2007; Ganguli and Reddy, 2014), or by analyzing the variability of drought indices (Santos et al, 2010; AghaKouchak, 2015; Mazdiyasni and AghaKouchak, 2015; Xu et al, 2015). NEB experiences high intensity of Drought Dynamics in Eastern Northeast Brazil hydrological extreme events and a large interannual variability of precipitation (Giannini et al, 2004). Precipitation in NEB is heterogeneous, ranging from an annual total of 300 mm in the semiarid region to 2000 mm in the coastal zone (Amorim et al, 2014; Campos, 2015; Cunha et al, 2015)
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