A Markov-chain model for assessing heatwaves and droughts in Iberian Peninsula

Abstract

The Iberian Peninsula subregion is known for the increasing frequency and intensity of heatwaves and drought conditions, but a comprehensive understanding of the statistical dependencies between these events is still underexplored. This undermines effective climate adaptation and mitigation strategies. We analyse ERA5 reanalysis daily mean temperature and precipitation data to investigate the statistical dependencies between heatwaves and drought conditions for the period 1950–2022 in the Iberian Peninsula. Through statistical analysis of precipitation and temperature data into binary states classifying the occurrence of heatwaves and droughts, we construct Markov-chain models describing the temporal sequence of these extreme events throughout the Iberian Peninsula. Moreover, using the binary states we introduce a similarity measure between pairs of geographic locations, based in the Hamming distance, which enables us to visualize a graph showing the most similar regions in Iberian Peninsula with respect to extreme climate events. We show that this statistical similarity changes significantly in time.