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HYDROLOGICAL VARIABILITY IN THE CAPIBARIBE RIVER BASIN IN THE 20TH AND 21ST CENTURIES

IWRA World Water Congress 2017 - Cancun Mexico
5. Water ecosystems and physical regimes
Author(s): Micaella Moura
Alfredo Ribeiro Neto
Maria Clara Santana
Bruna Campos
Suzana Montenegro

Micaella Moura
Federal University of Pernambuco
micaellaraissa@hotmail.com
Alfredo Ribeiro Neto
Federal University of Pernambuco
ribeiront@gmail.com
Maria Clara Santana
Federal University of Pernambuco
Bruna Campos
Federal University of Pernambuco
Suzana Montenegro
Federal University of Pernambuco
suzanam.ufpe@gmail.com


Keyword(s): climate variability, hydrological variability
Article:

Abstract

In the last decades there is a concern about analyzing climate variabilities that are occurring on the planet, especially as regards to a possible increase of some events, as heavy rainfalls or prolonged drought periods.The knowledge of rainfall variation during the year is a determinant factor to estimate, among others, irrigation needs and water supply. In this context, this work aimed to apply analysis methods of the temporal variability of precipitation and streamflow in Capibaribe River Basin (CRB), Pernambuco-Brazil, using the nonparametric Mann-Kendall and Pettit tests. The study was developed using measured precipitation series from 20th century and IPCC AR4 scenario simulations (Global Circulation Model HadCM3 nested in the Regional Climate Model Eta-CPTEC, ). Done in another work, the Eta-CPTEC simulations used four members of the HadCM3 perturbed physics ensemble, in which a single model structure is used and perturbations are introduced to the physical parameterization schemes in the model. The first member is the standard model structure (CTRL-control), and the other ones are perturbations of the physical parameterization schemes used to produce variants of the same model (LOW, MIDI and HIGH). The transformation of rainfall to streamflow was done with the hydrological model MODHAC. The CRB was divided into two regions, considering its climate characteristics: region 1 with dry climate and region 2 with humid climate. Initially the series were organized in average monthly data, but were later reorganized into annual averages. Both methods used are able to identify the change of the series tendency and the moment when it occurs. The identification of alterations in climate and hydrological regimes is an important step in order to evaluate the possible impacts that may be caused by climate changes.This fact is particularly important in arid and semi-arid regions, such as the upper Capibaribe River. In these regions, the vulnerability and consequences of changes are higher. Considering the CTRL type simulation, the rainfall and streamflow showed trend changing between 2013 and 2021, using the Mann-Kendall method.The results for the MIDI simulation showed that for the precipitation data in both regions there would be a trend changing between 2046 and 2066. The result for streamflow series was similar to that obtained for precipitation, with trend changing between 2041 and 2062.The analysis for 20th century showed no trend changing of the series. The results obtained by the present study may help to understand, for example, which factors can contribute to the occurrence of precipitation and streamflow anomalies, generating information that can also help the development of actions and policies to reduce economy impacts caused by climate and hydrological regime changes in the CRB.

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