The objective of the present study is to characterize the drought occurrences in a region comprising Paraguay, southern Brazil and northeastern Argentina. To recognize the drought occurrences the standardized precipitation index at the time-scales of 3 and 6 months was applied to the rainfall records from 1961 to 2011 at 51 rain gauges located in that region. After a drought regionalization using principal component analysis, a new approach, the Kernel occurrence rate estimation method coupled with bootstrap confidence band was used to quantify yearly drought occurrence rates. The study also includes the results of an additional and new approach based on rainfall threshold surfaces aimed at recognizing and monitoring the drought occurrence at the early stages of their development. For both time-scales, the study allowed identification of some spatial homogeneous regions regarding the severe droughts. In some of those regions, trends in the severe drought frequency occurrence were identified. The rainfall threshold surfaces, besides providing an adequate interpretation of the meaning of the standard precipitation index, can be quite easily and reliably utilized to identify the drought episodes.
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Research Article|November 27 2014
Drought analysis in southern Paraguay, Brazil and northern Argentina: regionalization, occurrence rate and rainfall thresholds
Maria Manuela Portela
Maria Manuela Portela
1Universidade de Lisboa, Instituto Superior Técnico, Lisbon, Portugal
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João Filipe dos Santos
João Filipe dos Santos
2Instituto Politécnico de Beja, Escola Superior de Tecnologia e Gestão de Beja, Beja, Portugal
E-mail: Joaof.santos@ipbeja.pt
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Artur Tiago Silva
Artur Tiago Silva
1Universidade de Lisboa, Instituto Superior Técnico, Lisbon, Portugal
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Julián Baez Benitez
Julián Baez Benitez
3Universidad Católica ‘Nuestra Señora de la Asunción’, Facultad de Ciencais y Tecnología, Asunción, Paraguay
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Carlos Frank
Carlos Frank
4Universidad Tecnológica Nacional, Facultad Regional Bahí-a Blanca, Bahía Blanca, Argentina
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José Miguel Reichert
José Miguel Reichert
5Universidade Federal de Santa Maria, Centro de Ciências Rurais, Santa Maria, Brazil
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Hydrology Research (2014) 46 (5): 792-810.
Article history
Received:
April 10 2014
Accepted:
October 18 2014
Citation
Maria Manuela Portela, João Filipe dos Santos, Artur Tiago Silva, Julián Baez Benitez, Carlos Frank, José Miguel Reichert; Drought analysis in southern Paraguay, Brazil and northern Argentina: regionalization, occurrence rate and rainfall thresholds. Hydrology Research 1 October 2015; 46 (5): 792–810. doi: https://doi.org/10.2166/nh.2014.074
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