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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Performance de modelo climárico de previsão da precipitação pluviométrica no Estado da Paraíba. / Performance of climatic model of precipitation forecast in Paraíba State.

LIMA, Nielza Macedo 19 October 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-10-19T18:41:21Z No. of bitstreams: 1 NIELZA MACEDO LIMA - DISSERTAÇÃO PPGMet 2001..pdf: 25624730 bytes, checksum: b3ea3a96769b05231b9b60ab18dea2b1 (MD5) / Made available in DSpace on 2018-10-19T18:41:21Z (GMT). No. of bitstreams: 1 NIELZA MACEDO LIMA - DISSERTAÇÃO PPGMet 2001..pdf: 25624730 bytes, checksum: b3ea3a96769b05231b9b60ab18dea2b1 (MD5) Previous issue date: 2001-12-18 / CNPq / O presente trabalho objetivou apresentar uma metodologia de previsão das chuvas que ocorrem no Estada da Paraíba, tendo por base o método das proporções apresentado por Silva (1988). Foram considerados 72 postos pluviométricos com mais de trinta anos de registros completos, distribuídos em três mesorregiões da Paraíba: mesorregião Ocidental (Sertões), Central (Cariris) e Oriental (Litoral, Agreste e Zona da Mata). Em cada mesorregião defmiu-se a correspondente estação chuvosa (EC) e diferentes sub-divisões das mesmas. As proporções Zj, razão entre as chuvas acumuladas no primeiro período (Xj) da EC e as chuvas de toda a EC, foram ajustadas ao modelo probabilístico Beta, usado para o cálculo dos quintis (primeiro e quarto) e da probabilidade de ocorrência de chuvas superior à média climatológica do segundo período (Yj) da EC. Avaliou-se a performance do modelo prognóstico por mesorregião nos anos de 1996 a 2001, inclusive. Nos anos de 1996 e 2000, com grande ocorrência de chuvas acima da média em Yj em todas as mesorregiões estudadas, o índice de acerto foi superior aos 80%, exceto para a EC8 em 2000. No ano de 1998, um ano muito seco, o índice foi inferior aos 80%, quando do prognóstico do total pluviométrico mínimo esperado. De um modo geral, a metodologia apresentada se mostrou consistente e de grande utilidade para a previsão de secas no Estado da Paraíba. / A methodology for forescating the acumulatcd rainfall (AR) in differcnt locations and mesoregions of Paraíba State, based on a model proposcd by Silva (1985,1988), was the objective of this study. A network of 72 rain stations, associated with three mesoregions of Paraíba State, were used. For each State mesoregion (Eastcrn, Central and Western) a rainy scason (RS) was established, with different subdivisions of them. The Beta probability distribution model was ajusted to lhe ratio betwccn lhe AR of the First period of the RS (Xi) and the total AR of the rainy season. That probabilislic model was used in the determination of statistical parameters (first - Ql and forth - Q4 quintis) and the probability of oceurrence of AR, in the second period of the RS, greater than the average of that same period, for each selected location. It was observed that in 1999 and 2000 therc were a great number of accumulated rainfall greater than the average of the second period (Yi) of the RS, for each of selected stations. The index of success, for the AR forecasted in those years, was greater than 80%, except for the RS denominated of EC8 in 2000. In 1998, considered a very dry year, the success index for oceurrence of the minimun AR was less than the expected valuc. Na important conclusion in that, the methodology presented is appropriated and seems to be am important tool for forecasting the oceurrence of drought in Paraíba State.

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