Increased risk of heat extremes in the Eastern Mediterranean during weak Indian summer monsoon years

Increased risk of heat extremes in the Eastern Mediterranean during weak Indian summer monsoon years | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Increased risk of heat extremes in the Eastern Mediterranean during weak Indian summer monsoon years Giorgia Di Capua, George Zittis, Theo Economou, Evangelos Tyrlis, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6887363/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Heat extremes in the eastern Mediterranean have increased 3-fold in the last decade, posing a severe threat to human health, socio-economic activities and ecosystems. During summer, northerly winds, called Etesians, can contribute to mitigating or exacerbating heat extremes. Here, we apply the Peter and Clark momentary conditional independence (PCMCI) algorithm to reanalysis data (ERA5) and seasonal forecasts (SEAS5.1), to assess the impact of the Indian summer monsoon (ISM) – Etesians teleconnection on the probability of heat extremes occurrence over the eastern Mediterranean. We find that weak Etesians, associated with suppressed ISM activity and warmer central tropical Pacific sea surface temperatures (El Niño phase), can increase the probability of heat extremes in the region up to 5-fold at 3-day timescales, and up to 2-fold at seasonal timescales. Moreover, over the 1981-2023 period, the effect of the mid-latitude circulation has weakened. In general, SEAS5.1 forecasts struggle to reproduce the dependency of the identified causal pathways originating from the ISM and El Niño intraseasonal variability, while it overestimates the effect of mid-latitude wave trains. These findings highlight that future changes in the ISM system could significantly affect the probability of heat extremes occurrence in the Mediterranean, while climate models might underestimate this link. Earth and environmental sciences/Climate sciences/Atmospheric science/Atmospheric dynamics Earth and environmental sciences/Climate sciences/Climate change/Climate and Earth system modelling Indian monsoon Mediterranean Etesians heat extremes predictability Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SIDiCapuaetalEMedheatwavesv2.pdf Supplementary information Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6887363","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":478972985,"identity":"7db38481-962c-4c70-be46-0edaf192d684","order_by":0,"name":"Giorgia Di 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During summer, northerly winds, called Etesians, can contribute to mitigating or exacerbating heat extremes. Here, we apply the Peter and Clark momentary conditional independence (PCMCI) algorithm to reanalysis data (ERA5) and seasonal forecasts (SEAS5.1), to assess the impact of the Indian summer monsoon (ISM) – Etesians teleconnection on the probability of heat extremes occurrence over the eastern Mediterranean. We find that weak Etesians, associated with suppressed ISM activity and warmer central tropical Pacific sea surface temperatures (El Niño phase), can increase the probability of heat extremes in the region up to 5-fold at 3-day timescales, and up to 2-fold at seasonal timescales. Moreover, over the 1981-2023 period, the effect of the mid-latitude circulation has weakened. 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