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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.
11

Sinergismo entre eventos clim?ticos extremos, desmatamento e aumento da suscetibilidade a inc?ndios florestais no Estado do Acre / Synergism between extreme weather events, deforestation and increased susceptibility and risk of forest fires in Acre state

Tostes, Juliana de Oliveira 29 February 2016 (has links)
Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2016-10-25T11:21:37Z No. of bitstreams: 1 2016 - Juliana de Oliveira Tostes.pdf: 4618564 bytes, checksum: 951350c8676b3f82092fedfc3a9e0f79 (MD5) / Made available in DSpace on 2016-10-25T11:21:37Z (GMT). No. of bitstreams: 1 2016 - Juliana de Oliveira Tostes.pdf: 4618564 bytes, checksum: 951350c8676b3f82092fedfc3a9e0f79 (MD5) Previous issue date: 2016-02-29 / This research analyzes the temporal and spatial variables that can affect the distribution and frequency of hot spots in the state of Acre. Given the scarcity of regular spatial information and long time series for the study area, it was initially carried out a validation between air temperature and precipitation data in Global Grid Precipitation Climatology Centre (GPCC), University of Delaware (UDEL) and Global Historical Climatology Network (GHCN) with data from five Weather Stations Mainstream (EMC) to Acre and region, through an analysis of precision and accuracy of the data. Regarding precipitation, it was found that both the GPCC UDEL represented as the average variability significantly throughout the series. In relation to the air temperature standards, although the accuracy of GHCN and UDEL was low, it was satisfactory accuracy according to statistical methods. Assuming that the extreme weather events increase susceptibility to forest fires, then it was carried out an analysis of the influence of climate variability modes in generating categorized scenarios dry or wet years, based on the Standardized Precipitation Index (SPI) and Harmonic and Spectral (AHE). It was found that the AHE is not able to identify the intensity of the events, but was satisfactory in the signal cycles identifying the anomaly, i.e., whether the abnormality SPI was positive or negative. It was found that the Atlantic signal had greater influence on the precipitation of the Pacific. For the regions that correspond to Groups 1, 2 and 3 there was an inverse pattern for precipitation in relation to ENSO compared to the North and East Amazon. Thus, it identified negative precipitation anomalies during La Ni?a and El Ni?o events during positive events for the dry and rainy seasons. For the area corresponding to the effect Group 4 was otherwise. The natural climate variability patterns identified in this study may contribute to the establishment of strategies for prevention and adaptation to extreme events. Finally, in Chapter 3 was carried out an analysis of the spatial and temporal patterns of the fire in Acre, through a discussion of various climatic, environmental and anthropogenic variables that contribute to its occurrence. Thus, through the Random Forest algorithm were generated susceptibility maps that estimated the probability of fires and burned in the state. . It was found that although drought triggers an increase in the number of hot spots, its spatial pattern is more related to human factors such as the proximity areas already cleared. / A presente pesquisa analisa as vari?veis temporais e espaciais que podem afetar a distribui??o e frequ?ncia dos focos de calor no estado do Acre. Diante da escassez de dados regularmente espacializados e com longa s?rie temporal para a ?rea de estudo, inicialmente foi realizada uma valida??o entre os dados de temperatura do ar e precipita??o em grade do Global Precipitation Climatology Centre (GPCC), Universidade de Delaware (UDEL) e Global Historical Climatology Network (GHCN) com dados de cinco Esta??es Meteorol?gicas Convencionais (EMC) para o Acre e regi?o, atrav?s de uma an?lise da precis?o e exatid?o dos dados. Em rela??o ? precipita??o, verificou-se que tanto o GPCC quanto da UDEL representaram significativamente as variabilidades m?dias ao longo da s?rie. Em rela??o aos padr?es da temperatura do ar, embora a precis?o do GHCN e da UDEL tenha sido baixa, a exatid?o foi satisfat?ria segundo os m?todos estat?sticos. Partindo do pressuposto que os eventos clim?ticos extremos aumentam a suscetibilidade a inc?ndios florestais, em seguida foi realizada uma an?lise da influ?ncia dos modos de variabilidade clim?tica na gera??o de cen?rios categorizados de anos secos ou ?midos, baseado no ?ndice de Precipita??o Padronizado (SPI) e na An?lise Harm?nica e Espectral (AHE). Verificou-se que a AHE n?o foi capaz de identificar a intensidade dos eventos, mas mostrou-se satisfat?ria na identifica??o dos ciclos de sinal da anomalia, ou seja, se anomalia do SPI foi positiva ou negativa. Verificou-se que o sinal do Atl?ntico teve maior influ?ncia sobre a precipita??o do que o Pac?fico. Para as regi?es que correspondem os Grupos 1, 2 e 3 observou-se um padr?o inverso para a precipita??o em rela??o ao ENOS, quando comparado com a Amaz?nia Norte e Oriental. Assim, foram identificadas anomalias negativas de precipita??o durante eventos de La Ni?a e positivas durante eventos de El Ni?o para as esta??es seca e chuvosa. Para a regi?o que corresponde ao Grupo 4 o efeito foi contr?rio. Os padr?es de variabilidade natural do clima identificados nesse trabalho podem contribuir para o estabelecimento de estrat?gias de preven??o e adapta??o aos eventos extremos. Finalmente, no Cap?tulo 3 foi realizada uma an?lise sobre o padr?o espacial e temporal do fogo no Acre, atrav?s de uma discuss?o sobre diversas vari?veis clim?ticas, ambientais e antr?picas que contribuem para a sua ocorr?ncia. Assim, por meio do algoritmo Random Forest foram gerados mapas de suscetibilidade que estimaram a probabilidade de ocorr?ncia de inc?ndios e queimadas no estado. Verificou-se que, embora a estiagem propicie um aumento do n?mero de focos de calor, o seu padr?o espacial est? mais relacionado a fatores antr?picos, tais como a proximidade de ?reas j? desmatadas.

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