In Portugal, drought characterizes the climatic variability, contributes to the increase of fire risk and its duration and intensity are expected to increase in future climate. Surprisingly, the quantitative and objective analysis to characterize the drought regime in current climate conditions as well as its influence on the occurrence of large wildfires (LW) has never been done for Portugal, which are the main objectives of this study. We assessed drought regime for recent past climate conditions (1981-2017), using four different drought indices, namely SPI, SPEI, RDI and VCI, and assessed the influence of drought in LW occurrence. Results include the characterization of drought number, duration, severity, intensity, extension, intra- and inter-annual variability for different classes of severity and the space-time distribution of LW in drought periods and affected area. Our main findings include 67% of the study period were drought months; regions with higher drought duration and severity assessed with SPI and SPEI for general drought conditions evolves from north to south with the increase of drought assessment period; drought characteristics present low intra - annual and inter - annual variability but are clearly associated to the temporal and spatial distribution of LW. In fact, all LW occurred during drought assessed with SPI or SPEI, almost all LW (97% to 95%) and corresponding burnt area (98% to 97%) occurred during drought assessed with SPI and SPEI. The relationship between drought and fire incidence is statistical significant for 3 - month SPI, 3 - and 6 - month SPEI, and is particularly strong for Moderate and Severe drought. 85% and 87% of LW occurred in area affected by drought assessed with SPI or SPEI, respectively. It is not clear which is the best index, but drought plays a fundamental role in the occurrence of large wildfires in Portugal.
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http://dx.doi.org/10.1016/j.scitotenv.2019.05.298 | DOI Listing |
Sci Rep
January 2025
Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia.
The Arabian Peninsula (AP) has been reported to experience increasing drought in recent decades. With this background, this study evaluates best performing Climate Model Intercomparison Project 6 (CMIP6) Global Climate Models (GCMs) for historical (1985-2014) simulations and future drought projections across the AP until 2100, using the standardized precipitation index (SPI) and standardized precipitation-evapotranspiration index (SPEI). We assess uncertainties from model differences, scenarios, timescales, and methods.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
January 2025
Department of Civil and Environmental Engineering, University of Perugia, Via Duranti 93, 06125, Perugia, Italy.
This study aims to analyze the performances and correlation of the standardized precipitation index (SPI) and standardized precipitation evaporation index (SPEI) from the perspective of supplying effective indicators for drought risk management prevention. Indices have been evaluated using long time series of precipitation and temperature data (from 1961 to 2020) gauged and validated in the land monitoring system of the Umbria region (central Italy). Results show how SPEI can evaluate better the drought phenomena, both in terms of occurred events and in terms of trends.
View Article and Find Full Text PDFEnviron Monit Assess
December 2024
Department of Geography and Disaster Management, School of Earth and Environmental Sciences, University of Kashmir, Srinagar, 190006, India.
Sci Rep
November 2024
Institute of Water Resources for Pastoral Area, China Institute of Water Resources and Hydropower Research, Hohhot, 010018, China.
Environ Monit Assess
October 2024
Department of Agricultural Meteorology, Anand Agricultural University, Anand, 388110, India.
The Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI), two drought indices, have been compared for interchangeability and reliability under various climatic conditions in Gujarat, India. As the quality of the input is crucial for the accuracy of the index, weather records from surface observatories are preferable over grid and reanalysis data. This study found that on a short timescale (1-3 months), SPEI diagnosed mild and moderate droughts more frequently than SPI, particularly in stations with relatively heavy rainfall.
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