Publicação
Impacto de cenários de alterações climáticas no regime de incêndios em Portugal
| Resumo: | Rural fires are a major environmental, social and economic problem in Portugal, where the fire is characterized by a large inter-annual variability largely due to climate variability. The main purpose of this study is to assess the potential impact of regional climate change on wildfires in Portugal using a Burnt Area Model (BAM) based on meteorological information. The model is able to predict the decimal logarithm of July (August) burnt areas using, as predictors, the cumulated precipitation in March and April together with a fire index, the DSR (Daily Severity Rating), in May and June, and in July (August). The model is then fed with simulated data by a GCM respecting to present climate and to future IPCC emissions scenarios (b1 and a1b). Comparative analysis of meteorological variables for future scenarios with those respecting to present climate simulated by the GCM and observed by ECMWF reveals that temperature tends to increase and relative humidity to decrease, precipitation is expected to decline, especially in late spring, and the wind speed is expected to remain without significant changes. Such changes in meteorological variables are responsible for a significant increase in both fire indices (FWI and DSR). It is shown that samples of observed and simulated logarithms of burnt areas follow normal distributions. When comparing present climate with future climate scenario b1 (a1b), there are increases in the means of the logarithm of July and August burnt area values of 11% (28%), the standard deviation remaining almost unchanged for scenario b1 and presenting an increase of 25% for a1b. Estimates should however be interpreted with caution, but the approach developed consistently points to an increased risk of fire in future climate conditions, a larger inter-annual variability and a higher likelihood of occurrence of large fire events. |
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| Autores principais: | Menezes, Tomás Leonardo Teixeira de Calheiros e |
| Assunto: | Impactos de alterações climáticas Cenário Fogo rural Regressão múltipla Risco de incêndio Teses de mestrado - 2010 |
| Ano: | 2010 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | português |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Rural fires are a major environmental, social and economic problem in Portugal, where the fire is characterized by a large inter-annual variability largely due to climate variability. The main purpose of this study is to assess the potential impact of regional climate change on wildfires in Portugal using a Burnt Area Model (BAM) based on meteorological information. The model is able to predict the decimal logarithm of July (August) burnt areas using, as predictors, the cumulated precipitation in March and April together with a fire index, the DSR (Daily Severity Rating), in May and June, and in July (August). The model is then fed with simulated data by a GCM respecting to present climate and to future IPCC emissions scenarios (b1 and a1b). Comparative analysis of meteorological variables for future scenarios with those respecting to present climate simulated by the GCM and observed by ECMWF reveals that temperature tends to increase and relative humidity to decrease, precipitation is expected to decline, especially in late spring, and the wind speed is expected to remain without significant changes. Such changes in meteorological variables are responsible for a significant increase in both fire indices (FWI and DSR). It is shown that samples of observed and simulated logarithms of burnt areas follow normal distributions. When comparing present climate with future climate scenario b1 (a1b), there are increases in the means of the logarithm of July and August burnt area values of 11% (28%), the standard deviation remaining almost unchanged for scenario b1 and presenting an increase of 25% for a1b. Estimates should however be interpreted with caution, but the approach developed consistently points to an increased risk of fire in future climate conditions, a larger inter-annual variability and a higher likelihood of occurrence of large fire events. |
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