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Índices de seca. Aplicação ao continente português
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Orientador(es)
Resumo(s)
The Palmer Drought Severity Index (PDSI) was tested along with two indices resulting from modifying its original formulation, one concerning the replacement of the Thornthwaite equation to compute potential evapotranspiration (ETP) by the FAO Penman-Monteith method, and the other consisting in replacing the soil water balance model and the ETP computation that passes to correspond to the ETP of an olive orchard, generating a new index: the MedPDSI. A factor for the normalization of the index, the climate characteristic (K), was reviewed and the index was calibrated for each analyzed location. The Standardized Precipitation Index (SPI) for the 9 and 12 month time-scales was also tested and compared with the three variants of the PDSI. The results revealed that the modification of K improved the standardization of the PDSI and that the calibration produced statistically improved results. It was found that the MedPDSI anticipates the initiation of droughts over the original PDSI, either with ETP Thornthwaite or with ETP FAO Penman-Monteith, and tends to classify droughts more severely than the first. The use of 9 month time-scale in the SPI is the one that best relates to the PDSI, since it clearly anticipates the onset of droughts relative to the 12 month scale.
Descrição
Mestrado em Engenharia Agronómica - Instituto Superior de Agronomia
Palavras-chave
evapotranspiration soil water balance climate characteristic calibration Palmer drought index standardized precipitation index
Contexto Educativo
Citação
Rosa, Ricardo Granés Tavares Duarte - Índices de seca. Aplicação ao continente português. Lisboa: ISA, 2011