Effects of climate change on the intensity and frequency of hot spells in northeastern Spain during the 21st century

The intensity and frequency of hot spells in northeastern Spain are simulated using data from ten different RCMs from the PRUDENCE and ENSEMBLE datasets for a control period (1970-2000) and three greenhouse emission scenarios (SRES A1, A2 and B2) for two sub-periods in the 21st century (2020-2050 and 2070-2100). Uncertainty in the predictions has been assessed by means of a set of validation statistics including: mean bias error (MBE), mean absolute error (MAE), root mean square error (RMSE) and D Williomtt statistic. Possible changes in the frequency and intensity of these high-frequency temperature events are projected with the A1, A2 and B2 scenarios. Comparisons between future and control simulations enabled a quantification of these expected changes across the study domain. Our results demonstrate a statistically significant increase in the frequency and intensity of these hot events under the A1 and A2 greenhouse gas emission scenarios. Under these scenarios, considerable spatial variability has also been observed, particularly along the coastal and highly elevated regions (e.g. the Pyrenees). Our results could help to better understanding hot spells snow evolution in the future, which could have potential implications for hydrological modeling, environmental management and various human activities.