El Niño | National Geographic Society

El Niño is a climate pattern that describes the unusual warming of surface waters in the eastern tropical Pacific Ocean. El Nino is the ... ResourceLibraryENCYCLOPEDICENTRYResourceLibraryENCYCLOPEDICENTRYElNiñoElNiñoElNinoisaclimatepatternthatdescribestheunusualwarmingofsurfacewatersintheeasternPacificOcean.Grades10-12+SubjectsBiology,EarthScience,Ecology,Geography,Meteorology,Oceanography,PhysicalGeographyEncyclopedicEntryVocabularyElNiñoisaclimatepatternthatdescribestheunusualwarmingofsurfacewatersintheeasterntropicalPacificOcean.ElNinoisthe“warmphase”ofalargerphenomenoncalledtheElNino-SouthernOscillation(ENSO).LaNina,the“coolphase”ofENSO,isapatternthatdescribestheunusualcoolingoftheregion’ssurfacewaters.ElNiñoandLaNiñaareconsideredtheoceanpartofENSO,whiletheSouthernOscillationisitsatmosphericchanges.ElNiñohasanimpactonoceantemperatures,thespeedandstrengthofoceancurrents,thehealthofcoastalfisheries,andlocalweatherfromAustraliatoSouthAmericaandbeyond.ElNiñoeventsoccurirregularlyattwo-toseven-yearintervals.However,ElNiñoisnotaregularcycle,orpredictableinthesensethatoceantidesare.ElNiñowasrecognizedbyfishersoffthecoastofPeruastheappearanceofunusuallywarmwater.WehavenorealrecordofwhatindigenousPeruvianscalledthephenomenon,butSpanishimmigrantscalleditElNiño,meaning“thelittleboy”inSpanish.Whencapitalized,ElNiñomeanstheChristChild,andwasusedbecausethephenomenonoftenarrivedaroundChristmas.ElNiñosooncametodescribeirregularandintenseclimatechangesratherthanjustthewarmingofcoastalsurfacewaters.LedbytheworkofSirGilbertWalkerinthe1930s,climatologistsdeterminedthatElNiñooccurssimultaneouslywiththeSouthernOscillation.TheSouthernOscillationisachangeinairpressureoverthetropicalPacificOcean.WhencoastalwatersbecomewarmerintheeasterntropicalPacific(ElNiño),theatmosphericpressureabovetheoceandecreases.ClimatologistsdefinetheselinkedphenomenaasElNiño-SouthernOscillation(ENSO).Today,mostscientistsusethetermsElNiñoandENSOinterchangeably.ScientistsusetheOceanicNinoIndex(ONI)tomeasuredeviationsfromnormalseasurfacetemperatures.ElNiñoeventsareindicatedbyseasurfacetemperatureincreasesofmorethan0.9°Fahrenheitforatleastfivesuccessivethree-monthseasons.TheintensityofElNiñoeventsvariesfromweaktemperatureincreases(about4–5°F)withonlymoderatelocaleffectsonweatherandclimatetoverystrongincreases(14–18°F)associatedwithworldwideclimaticchanges.UpwellingInordertounderstandthedevelopmentofElNiño,it’simportanttobefamiliarwithnon-ElNiñoconditionsinthePacificOcean.Normally,strongtradewindsblowwestwardacrossthetropicalPacific,theregionofthePacificOceanlocatedbetweentheTropicofCancerandtheTropicofCapricorn.ThesewindspushwarmsurfacewatertowardsthewesternPacific,whereitbordersAsiaandAustralia.Duetothewarmtradewinds,theseasurfaceisnormallyabout.5meter(1.5feet)higherand45°FwarmerinIndonesiathanEcuador.ThewestwardmovementofwarmerwaterscausescoolerwaterstoriseuptowardsthesurfaceonthecoastsofEcuador,Peru,andChile.Thisprocessisknownasupwelling.Upwellingelevatescold,nutrient-richwatertotheeuphoticzone,theupperlayeroftheocean.Nutrientsinthecoldwaterincludenitratesandphosphates.Tinyorganismscalledphytoplanktonusethemforphotosynthesis,theprocessthatcreateschemicalenergyfromsunlight.Otherorganisms,suchasclams,eattheplankton,whilepredatorslikefishormarinemammalspreyonclams.Upwellingprovidesfoodforawidevarietyofmarinelife,includingmostmajorfisheries.FishingisoneoftheprimaryindustriesofPeru,Ecuador,andChile.Someofthefisheriesincludeanchovy,sardine,mackerel,shrimp,tuna,andhake.Theupwellingprocessalsoinfluencesglobalclimate.ThewarmoceantemperatureinthewesternPacificcontributestoincreasedrainfallaroundtheislandsofIndonesiaandNewGuinea.TheairinfluencedbythecooleasternPacific,alongthecoastofSouthAmerica,remainsrelativelydry.ElNiñoEventsElNiñoeventsaredefinedbytheirwide-rangingteleconnections.Teleconnectionsarelarge-scale,long-lastingclimateanomaliesorpatternsthatarerelatedtoeachotherandcanaffectmuchoftheglobe.DuringanElNiñoevent,westward-blowingtradewindsweakenalongtheEquator.ThesechangesinairpressureandwindspeedcausewarmsurfacewatertomoveeastwardalongtheEquator,fromthewesternPacifictothecoastofnorthernSouthAmerica.Thesewarmsurfacewatersdeepenthethermocline,thelevelofoceandepththatseparateswarmsurfacewaterfromthecolderwaterbelow.DuringanElNiñoevent,thethermoclinecandipasfaras152meters(500feet).Thisthicklayerofwarmwaterdoesnotallownormalupwellingtooccur.Withoutanupwellingofnutrient-richcoldwater,theeuphoticzoneoftheeasternPacificcannolongersupportitsnormallyproductivecoastalecosystem.Fishpopulationsdieormigrate.ElNiñohasadevastatingimpactonEcuadorianandPeruvianeconomies.ElNiñoalsoproduceswidespreadandsometimesseverechangesintheclimate.Convectionabovewarmersurfacewatersbringincreasedprecipitation.RainfallincreasesdrasticallyinEcuadorandnorthernPeru,contributingtocoastalfloodinganderosion.Rainsandfloodsmaydestroyhomes,schools,hospitals,andbusinesses.Theyalsolimittransportationanddestroycrops.AsElNiñobringsraintoSouthAmerica,itbringsdroughtstoIndonesiaandAustralia.Thesedroughtsthreatentheregion’swatersupplies,asreservoirsdryandriverscarrylesswater.Agriculture,whichdependsonwaterforirrigation,isthreatened.StrongerElNiñoeventsalsodisruptglobalatmosphericcirculation.Globalatmosphericcirculationisthelarge-scalemovementofairthathelpsdistributethermalenergy(heat)acrossthesurfaceoftheEarth.TheeastwardmovementofoceanicandatmosphericheatsourcescauseunusuallyseverewinterweatheratthehigherlatitudesofNorthandSouthAmerica.RegionsasfarnorthastheU.S.statesofCaliforniaandWashingtonmayexperiencelonger,colderwintersbecauseofElNiño.ElNiñoeventsof1982-83and1997-98werethemostintenseofthe20thcentury.Duringthe1982-83event,seasurfacetemperaturesintheeasterntropicalPacificwere9-18°Fabovenormal.Thesestrongtemperatureincreasescausedsevereclimaticchanges:Australiaexperiencedharshdroughtconditions;typhoonsoccurredinTahiti;andrecordrainfallandfloodinghitcentralChile.ThewestcoastofNorthAmericawasunusuallystormyduringthewinterseason,andfishcatchesweredramaticallyreducedfromChiletoAlaska.TheElNiñoeventof1997-98wasthefirstElNiñoeventtobescientificallymonitoredfrombeginningtoend.The1997-98eventproduceddroughtconditionsinIndonesia,Malaysia,andthePhilippines.Peruexperiencedveryheavyrainsandsevereflooding.IntheUnitedStates,increasedwinterrainfallhitCalifornia,whiletheMidwestexperiencedrecord-breakingwarmtemperaturesduringaperiodknownas“theyearwithoutawinter.”ElNiño-relateddisruptionofglobalatmosphericcirculationextendsbeyondPacificRimnations.StrongElNiñoeventscontributetoweakermonsoonsinIndiaSoutheastAsia.ENSOhasevencontributedtoincreasedrainfallduringtherainyseasoninsub-SaharanAfrica.Diseasesthriveincommunitiesdevastatedbynaturalhazardssuchasfloodordrought.ElNiño-relatedfloodingisassociatedwithincreasesincholera,dengue,andmalariainsomepartsoftheworld,whiledroughtcanleadtowildfiresthatproducerespiratoryproblems.'Flavors'ofElNiñoVariationsofElNiñoarereferredtoas“flavors.”ThetransitionperiodofanElNiñoevent,forinstance,iscalleda"TransNiño."TransNiñoeventsoccurattheonsetandclosingofanElNiñoevent.TransNiñoeventsoftenincludeincreasedtornadoactivityintheAmericanMidwest.Another"flavor"ofElNiñoistheElNiñoModoki,orModokiNiño.ModokiisaJapanesewordmeaning"similar,butdifferent."ModokiNiño,alsocalledtheCentralPacificNiño,ischaracterizedbychangesinsea-surfacetemperaturesinthecentral,noteastern,Pacific.SomeModokiNiñoeventsaredistinctfromtraditionalElNiñoevents,suchasincreasedhurricaneactivityintheAtlanticandGulfofMexico.ManymeteorologistsarecriticaloftheModokiNiño,callingformoreclimatemodelstostudytheproposedphenomenon.MonitoringElNiño Scientists,governments,andnon-governmentalorganizations(NGOs)collectdataaboutElNiñousinganumberoftechnologies.TheNationalOceanicandAtmosphericAdministration(NOAA),forinstance, operatesanetworkofscientificbuoys.Thesebuoysmeasureoceanandairtemperatures,currents,winds,andhumidity.Thebuoysarelocatedatabout70locationsinthesouthernPacificOcean,fromtheGalapagosIslandstoAustralia.Thesebuoystransmitdatadailytoresearchersandforecastersaroundtheworld.Usingdatafromthebuoys,alongwithvisualimagerytheyreceivefromsatelliteimagery,scientistsareabletomoreaccuratelypredictElNiñoandvisualizeitsdevelopmentandimpactaroundtheglobe.FastFactFertilizerElNiñodevastateswesternSouthAmericanfisheries—andalsofertilizerindustries.TheSouthAmericanfertilizerindustryisdrivenbythedroppingsofseabirds,whosepopulationdeclinesduringElNiñoeventsduetoareductionintheirfoodsource(fish).FastFactOlympicElNiño ElNiñoputadamperonthe2010WinterOlympicsinVancouver,BritishColombia,Canada.Theweatherpatternbroughtunseasonablywarmweathertothenormallychillycoastaltown.FastFactIntheRingsScientistsareabletodetectanElNiño eventanditseffectsontheclimatethroughavarietyoftechnologicalandnaturalsciences.Oneofthesenaturalsciencesisdendrochronology,orthestudyoftreerings.Dendrochronologistsstudytheringsofatreeinordertounderstandclimaticconditionsduringspecifictimeperiods.Thinringsoftenindicatedrierseasonswhilefatterringsindicaterainyseasons.Dependingonwherethetreeis,scientistscanseepastElNiño eventsintreesthatexhibitsignsofmuchrainierordrierseasonsthatnormal.Articles&ProfilesNationalGeographicMagazine:ElNiño—Nature'sViciousCycleNOAA:ElNiñoThemePage—FAQsTheUniversityCorporationforAtmosphericResearch:ElNiño,LaNiña,&ENSOFAQClimate.gov:September2015ElNiñoUpdateandQ&AInstructionalContentNationalGeographicEducation:WhatYouNeedtoKnowaboutElNiñoArticleNOAA:NOAA'sElNiñoPageCreditsMediaCreditsTheaudio,illustrations,photos,andvideosarecreditedbeneaththemediaasset,exceptforpromotionalimages,whichgenerallylinktoanotherpagethatcontainsthemediacredit.TheRightsHolderformediaisthepersonorgroupcredited.EditorJeannieEvers,EmdashEditing,EmdashEditingProducerNationalGeographicSocietyotherLastUpdatedMay20,2022UserPermissionsForinformationonuserpermissions,pleasereadourTermsofService.Ifyouhavequestionsaboutlicensingcontentonthispage,pleasecontactngimagecollection@natgeo.comformoreinformationandtoobtainalicense.Ifyouhavequestionsabouthowtociteanythingonourwebsiteinyourprojectorclassroompresentation,pleasecontactyourteacher.Sheorhewillbestknowthepreferredformat.Whenyoureachouttohimorher,youwillneedthepagetitle,URL,andthedate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