Marine Heatwaves in the Mediterranean Sea: a comparative analysis of CMIP6 and MedCORDEX model outputs

Marine heatwaves (MHWs) are characterized by exceptionally high ocean temperatures that persist over extended periods, leading to abrupt and profound changes in marine biodiversity and ecosystem functioning. These events have garnered increasing attention from both the research community and societal stakeholders due to their significant implications for economic activities, including fishing and aquaculture. Over the past decades, climate change has modified the frequency, duration and intensity of MHWs in the Mediterranean Sea, urging the need for precise characterization of current and future events. 

ObsSea4Clim is an EU project dedicated to improving sustained and multipurpose observations vital to European and global climate requirements. The project aims to develop new regional indicators for MHWs to enhance understanding and monitoring of marine extremes, ultimately contributing to more effective ocean management and climate adaptation strategies. Within the framework of ObsSea4Clim, the CMCC is committed to advancing knowledge on MHWs by establishing and evaluating these new indicators in reanalysis datasets, historical simulations, and projection scenarios provided by Earth System Models (ESMs). We will show preliminary results on how MHWs indicators are represented in the Mediterranean Sea across different downscaling products from the MedCORDEX initiative and their parent ESMs. In particular, we aim to highlight the added value given by such downscaling exercise in the assessment of present and future MHWs characteristics in the Mediterranean Sea. This work represents the first step in determining minimum requirements, such as resolution and frequency, necessary for accurately representing MHWs indicators in the next generation of climate models (CMIP7).