[{"command":"openDialog","selector":"#drupal-modal","settings":null,"data":"\u003Cdiv id=\u0022republish_modal_form\u0022\u003E\u003Cform class=\u0022modal-form-example-modal-form ecl-form\u0022 data-drupal-selector=\u0022modal-form-example-modal-form\u0022 action=\u0022\/en\/article\/modal\/7409\u0022 method=\u0022post\u0022 id=\u0022modal-form-example-modal-form\u0022 accept-charset=\u0022UTF-8\u0022\u003E\u003Cp\u003EHorizon articles can be republished for free under the Creative Commons Attribution 4.0 International (CC BY 4.0) licence.\u003C\/p\u003E\n \u003Cp\u003EYou must give appropriate credit. We ask you to do this by:\u003Cbr \/\u003E\n 1) Using the original journalist\u0027s byline\u003Cbr \/\u003E\n 2) Linking back to our original story\u003Cbr \/\u003E\n 3) Using the following text in the footer: This article was originally published in \u003Ca href=\u0027#\u0027\u003EHorizon, the EU Research and Innovation magazine\u003C\/a\u003E\u003C\/p\u003E\n \u003Cp\u003ESee our full republication guidelines \u003Ca href=\u0027\/horizon-magazine\/republish-our-stories\u0027\u003Ehere\u003C\/a\u003E\u003C\/p\u003E\n \u003Cp\u003EHTML for this article, including the attribution and page view counter, is below:\u003C\/p\u003E\u003Cdiv class=\u0022js-form-item form-item js-form-type-textarea form-item-body-content js-form-item-body-content ecl-form-group ecl-form-group--text-area form-no-label ecl-u-mv-m\u0022\u003E\n \n\u003Cdiv\u003E\n \u003Ctextarea data-drupal-selector=\u0022edit-body-content\u0022 aria-describedby=\u0022edit-body-content--description\u0022 id=\u0022edit-body-content\u0022 name=\u0022body_content\u0022 rows=\u00225\u0022 cols=\u002260\u0022 class=\u0022form-textarea ecl-text-area\u0022\u003E\u003Ch2\u003EWhy climate change could make Mediterranean atmospheric \u2018meteotsunamis\u2019 more common\u003C\/h2\u003E\u003Cp\u003EA meteotsunami is a form of tsunami generated by atmospheric conditions, and it can strike any coastline adjacent to a sea floor with a long, shallow shelf. They are not as massive, nor as well-known, as ordinary tsunamis, which are caused by earthquakes in the ocean floor, and they are more localised. But they can damage property and endanger human life.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EA meteotsunami in the harbour of Ciutadella on the Spanish island of Menorca in 2006, for example, sent yachts crashing into each other and then dumped them on the harbour floor as it drained away, causing \u003Ca href=\u0022https:\/\/link.springer.com\/article\/10.1007\/s00024-008-0426-5\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003Etens of millions of euros\u003C\/a\u003E in damage. Meteotsunamis also feature in local legends \u2013 one meteotsunami in sixteenth century Croatia swept away the bridge that linked two sides of a village bringing them to their senses over a feud that had arisen between them.\u003C\/p\u003E\u003Cp\u003EResearchers already understand the conditions that trigger such tsunamis, according to Professor Jadranka \u0160epi\u0107, an assistant professor and meteorologist at the University of Split, Croatia.\u003C\/p\u003E\u003Cp\u003EAt the coast, there must be a drop down to a shallow shelf of up to 100m deep that juts out at least a few tens of kilometres into the sea. Such a feature is found on the east coast of the United States and in the channel between France and England, for example.\u003C\/p\u003E\u003Cp\u003EThis shape has an effect on the speed of long-ocean waves \u2013 those that travel over long distances\u0026nbsp;rather than the wind-caused breakers that hit the shoreline every few seconds. When these 10km-long waves reach this kind of shelf they slow down to a speed of 50 to 110 kilometres per hour, depending on the depth.\u003C\/p\u003E\u003Cp\u003ECrucially, this can be slow enough to match the speed of atmospheric gravity waves above them. If the two speeds coincide, and if the two sets of waves then synchronise, energy from the atmospheric wave siphons down into that of the wave in the water, \u2018and this wave in the sea grows bigger and bigger, kind of like a resonance,\u2019 said Prof. \u0160epi\u0107.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cblockquote class=\u0022tw-text-center tw-text-blue tw-font-bold tw-text-2xl lg:tw-w-1\/2 tw-border-2 tw-border-blue tw-p-12 tw-my-8 lg:tw-m-12 lg:tw--ml-16 tw-float-left\u0022\u003E\n \u003Cspan class=\u0022tw-text-5xl tw-rotate-180\u0022\u003E\u201c\u003C\/span\u003E\n \u003Cp class=\u0022tw-font-serif tw-italic\u0022\u003E\u2018So at the surface it looks fine, but at high levels there is something happening that is more energetic.\u2019\u003C\/p\u003E\n \u003Cfooter\u003E\n \u003Ccite class=\u0022tw-not-italic tw-font-normal tw-text-sm tw-text-black\u0022\u003EProf. Jadranka \u0160epi\u0107, University of Split, Croatia\u003C\/cite\u003E\n \u003C\/footer\u003E\n\u003C\/blockquote\u003E\n\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EAtmospheric waves\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EBut what causes those atmospheric waves is less well understood, says Prof. \u0160epi\u0107. She leads a project known as \u003Ca href=\u0022https:\/\/cordis.europa.eu\/project\/id\/853045\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003ESHExtreme\u003C\/a\u003E to discover the processes behind them and whether they will be more common as the climate changes.\u003C\/p\u003E\u003Cp\u003E\u2018We know how the atmosphere and the ocean interact \u2026 but we want to find out what exactly helps these processes in the atmosphere to develop, what kind of larger setting in the atmosphere allows for these smaller processes,\u2019 she said.\u003C\/p\u003E\u003Cp\u003EIf they increase in incidence, she points out, then there will be a corresponding increase in the incidence of the biggest meteotsunamis. What\u2019s more, because of sea level rise, they will have a further reach than today.\u003C\/p\u003E\u003Cp\u003E\u2018The first thing is they will happen from a higher sea level so they will be more dangerous,\u2019 said Prof. \u0160epi\u0107. \u2018But the second thing we need to check is what will happen to these atmospheric waves \u2013 will they happen more often or less often? If they happen less often it could happen that these two events cancel each other \u2026 but if we have \u2026 more of these favourable atmospheric processes then there is a problem: you have a meteotsunami which is more likely to happen and which will start from a higher level.\u2019\u003C\/p\u003E\u003Cp\u003ESHExtreme is collecting evidence of previous such waves and comparing them with the atmospheric processes going on at the time.\u003C\/p\u003E\u003Cp\u003ETo do so requires tidal data which has been collected by mechanical tide gauges as far back as the 19\u003Csup\u003Eth\u003C\/sup\u003E century, and is now mostly recorded through digital radar and pressure sensors on the sea floor.\u003C\/p\u003E\u003Cp\u003EFor the more historical work, however, there was a hitch. Tables of sea level data before around 2010 register the height only every hour. This is too coarse a measurement because a meteotsunami could roll in, do its damage and depart in just a few minutes.\u003C\/p\u003E\u003Cp\u003EBecause of this, Prof. \u0160epi\u0107 has had to find the original analogue charts \u2013 made by a needle wavering up and down a rotating cylinder \u2013 from which the tables were compiled. She is working through these records for the whole of the Croatian coast. Colleagues, meanwhile, have done the same for Finland.\u003C\/p\u003E\u003Cp\u003ESince 2010, the International Oceanographic Commission has been providing\u0026nbsp;sea level height measurements taken around the globe every minute. So Prof. \u0160epi\u0107\u2019s team is prioritising study of this period, looking for patterns in the data such as seasonal distributions and the breadth of coastline affected.\u003C\/p\u003E\u003Cp\u003E\u003Cfigure role=\u0022group\u0022 class=\u0022@alignleft@\u0022\u003E\n\u003Cimg alt=\u0022Research has shown that Mediterranean meteotsunamis tend to be stronger in the summer because of fast winds of dry air from Africa. Image credit - Jorge Garcia \/ Unsplash \u0022 height=\u0022483\u0022 src=\u0022\/sites\/default\/files\/hm\/IMCEUpload\/jorge-garcia-9jfuqp-bciu-unsplash_0.jpg\u0022 title=\u0022Research has shown that Mediterranean meteotsunamis tend to be stronger in the summer because of fast winds of dry air from Africa. Image credit - Jorge Garcia \/ Unsplash \u0022 width=\u0022983\u0022\u003E\n\u003Cfigcaption class=\u0022tw-italic tw-mb-4\u0022\u003EResearch has shown that Mediterranean meteotsunamis tend to be stronger in the summer because of fast winds of dry air from Africa. Image credit - Jorge Garcia \/ Unsplash\u003C\/figcaption\u003E\n\u003C\/figure\u003E\n\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ESummer\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003ESo far, the team has shown that Mediterranean meteotsunamis tend to be stronger in the summer. Despite calm conditions at ground level, fast winds of dry air from Africa can be racing through the atmosphere some 1,500 metres up and this is what seems to trigger the atmospheric waves.\u003C\/p\u003E\u003Cp\u003E\u2018At the surface it looks fine, but at high levels there is something happening that is more energetic,\u2019 she said. Testing this theory for Spain\u2019s Balearic Islands coasts, she said \u2018we were able to show that, if you have this situation in the atmosphere, there is a very high chance that a meteotsunami will happen \u2013 this situation almost always generates these atmospheric waves\u2019.\u003C\/p\u003E\u003Cp\u003EThe next step is to consider the future. There are many simulations of how the atmosphere will behave under climate change. For the Balearic Islands, the worst-case scenario of one simulation revealed a 30% increase in the number of days favourable to meteotsunamis because of an increase in the number of days during which there are these high-level winds.\u003C\/p\u003E\u003Cp\u003E\u2018But the problem is we used only one climate simulation \u2013 this was like a prototype model,\u2019 said Prof. \u0160epi\u0107. \u2018You need to look at ten or 20 climate simulations.\u2019\u003C\/p\u003E\u003Cp\u003ELooking at more simulations\u0026nbsp;is something she plans to do in the next couple of years.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EScientists in the United States think they have made a breakthrough in forecasting meteotsunamis, at least for Lake Michigan. In April 2018 the beach town of Ludington was drenched by a wave that damaged boat docks and homes, flooded intake pipes \u2013 and could have carried away beach-goers if it had happened a little later in the year.\u003C\/p\u003E\u003Cp\u003E\u2018It\u2019s a gap in our forecasting,\u2019 said Dr Eric Anderson, an oceanographer at the National Oceanic and Atmospheric Administration\u2019s Great Lakes Environmental Research Laboratory.\u003C\/p\u003E\u003Cp\u003EHis team reported in late March that, using photos taken by a local resident, and other data, they should, with existing forecasting tools, be able to \u003Ca href=\u0022https:\/\/www.hstoday.us\/subject-matter-areas\/emergency-preparedness\/new-study-shows-promise-of-forecasting-meteotsunamis\/\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003Epredict\u003C\/a\u003E such an event minutes to hours in advance.\u003C\/p\u003E\u003Cp\u003EProf. \u0160epi\u0107 says that forecasting is already in place for the Balearics but they are \u2018often wrong,\u2019 because they are based either on a statistical chance according to the atmospheric conditions or on models that cannot give precise forecasts of atmospheric waves at small scale.\u003C\/p\u003E\u003Cp\u003ESHExtreme may change that. At the very least, Prof. \u0160epi\u0107 said, \u2018we hope we will be able to show which parts of the European coast are in most danger now and also in the future.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003E\u003Cstrong\u003EJust how are our seas changing and rising with climate change and the melting of Earth\u2019s ice caps? In this three-part \u003C\/strong\u003E\u003C\/em\u003E\u003Ca href=\u0022https:\/\/horizon-magazine.eu\/article\/series-our-rising-seas.html\u0022\u003E\u003Cem\u003E\u003Cstrong\u003Eseries\u003C\/strong\u003E\u003C\/em\u003E\u003C\/a\u003E\u003Cem\u003E\u003Cstrong\u003E, we look at\u0026nbsp;the past, present and future of extreme sea level rise. In part three we will look at how habitants of cities with high flood protection are paradoxically put more at risk of extreme flooding. In \u003C\/strong\u003E\u003C\/em\u003E\u003Ca href=\u0022https:\/\/horizon-magazine.eu\/article\/impossible-adapt-surprisingly-fast-ice-melts-past-raise-fears-about-sea-level-rise.html\u0022\u003E\u003Cem\u003E\u003Cstrong\u003Epart one\u003C\/strong\u003E\u003C\/em\u003E\u003C\/a\u003E\u003Cem\u003E\u003Cstrong\u003E, we looked at what the last interglacial can tell us about extreme sea level rise.\u003C\/strong\u003E\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThe research in this article was funded by the EU\u2019s European Research Council. 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