| ABSTRACT | Heat waves are defined as pronlonged periods of extremely hot weather and their magnitude and frequency are expected to increase over the next.
Here we present a new Heat Wave Magnitude Index (HWMI) based on the analysis of daily maximum temperature,
in order to classify the strongest heat waves that occurred in the Mediterranean region during three study periods
1980-1990, 1991-2001 and 2002-2012. In addition results
from five different regional climate models provided by the ENSEMBLES project, and from the COordinated
Regional climate Downscaling EXperiment (CORDEX) are used to project future occurrence and severity of heat
waves, under different emission scenarios, i.e. A1B, RCP4.5 and RCP8.5. Understanding and quantifying on a
unique scale the present-day heat waves is a crucial basis for a reliable projection into the future. By analyzing observed and
modelled daily maximum temperatures in current climates, we conclude that in the Mediterranean heat waves
have been increasing in frequency and magnitude in the most recent
period 2002-2012 compared to the two earlier eleven-year periods. Moreover, model predictions suggest an
increased probability of occurrence of severe heat waves in the coming 30-90 years: in particular, by the end of
the century events of the same severity as the 2003 summer heat wave are projected to occur as often as every two
years in the studied region. |