Assessing the role of drought events on wildfires in the Iberian Peninsula

- Strong relation between short timescales of drought and burned areas.
- Drought promotes a synchronous influence on burned areas over a great part of the IP.
- Drought promotes an asynchronous influence on burned areas on Central Iberia.
- The influence of the spring precipitation dominates on the central sector.
- Evapotranspiration dominates during summer on most of the Portuguese provinces.

Southern European countries are particularly affected by summer wildfires and drought events. The occurrence of extreme meteorological conditions during preceding and contemporaneous months amplifies the risk of summer wildfires.The main scope of this study was to investigate the impact of drought periods on burned areas in the Iberian Peninsula. This will be achieved through the comparison of time series of two widely used multi-scalar drought indices (SPI and SPEI) calculated for each province and then associated with the time series of the standardized logarithm of normalized burned areas during the fire summer season. The SPI and SPEI were both calculated for the time scales spanning between 2 to 12 months and for each month from January to August, between 1980 and 2005. Based on the regression analysis between drought indicators and burned areas, the months that present lowest errors were identified for each province. From the obtained results two main conclusions were reached: (i) the association between drought and fires is a local scale process and should be analyzed at the province or sub-province level rather than at the country or continental level; (ii) the relation between wildfires and drought is better explained by the influence of the spring precipitation on the central sector and by the influence of temperature and precipitation during summer on most of the Portuguese provinces.