Comparison of mega-heatwaves in preindustrial and present-day simulations over Europe

Heatwaves are likely to occur more frequent, longer, and stronger due to the rise in CO2 concentrations. It is related to the change in the mean of a climate distribution, as well as through the change in variance. Mega-heatwaves, in particular, have a crucial impact on human health. Many studies are trying to understand the mechanisms of mega-heatwaves and also their characteristics included amplitude, duration, frequency. In spite of these efforts, researches are limited because of the small number of mega-heatwaves. In order to overcome these limitations, Earth system model should be needed. This study aims to figure out the comprehensive characteristics of mega-heatwaves using Community Earth System Model (CESM). First, the possibility of the occurrence of mega-heatwaves in preindustrial period in Europe was analyzed. Second, the relation between decadal climate variabilities and mega-heatwaves was investigated. In addition, changes in characteristics of mega-heatwaves were compared between preindustrial and present-day simulations.