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1、ElNino&LaNiñaEverybodywantstoknowwhattheweatherisgoingtodoeachday--andwithgoodreason,consideringthemanydestructivestormsandtornadoesthathavehitourearthIn1997-1998,theweathereffectknownasElNiñohasbeenafavoritetopicofconversation,asitseemstohavecausedmostofthoseweatherwoes
2、.ButjustwhatisElNiño?It'saperiodicdisruptionofthePacific'sclimaticsystem.What'sinaname?Theterm“ElNiño,”whichreferstotheChristchild（圣婴）,wasgiventothisweatherpatternbyPeruvian（秘鲁的）fishermenwhonoticedthatwarmcurrentsarrivedoneyearatChristmastime.Onaverage,ElNiñooccurseveryt
3、wotosevenyears.WarmupwellingWarmdownwellingTradedriftandwindWalkercirculationcell (沃克环流圈)NSPacificoceanUsually,thewindblowsstronglyfromeasttowestalongthee’quator(赤道)inthePacific.Thisactuallypilesup(堆积)water(abouthalfameter'sworth)inthewesternpartofthePacific.Intheeastern
4、region,deeperwater(whichiscolderthanthesun-warmedsurfacewater)getspulledupfrombelowtoreplacethewaterpushedwest.So,thenormalsituationiswarmwater(about30C)inthewest,cold(about22C)intheeast.WarmupwellingWarmdownwellingCycloneDuringanElNiñoperiod,thewindspushingthatwaterarou
5、ndweaken.Asaresult,someofthewarmwaterpiledupinthewestslumpsbackdowntotheeast,andnotasmuchcoldwatergetspulledupfrombelow.BoththesetendtomakethewaterintheeasternPacificwarmer.Butitdoesn'tstopthere.Thewarmeroceanwaterthenaffectsthewindsbylesseningtheirstrength!Soifthewindsg
6、etweaker,thentheoceancontinuestogetwarmer.ThispositivefeedbackiswhatmakesElNiñogrow.ImpactsManyplaceshaveseenextrarainin1998.ThisElNiñohashadsomenotableeffects.RainfallinsoutheastAsiawasfarbelownormalin1997-1998,whilerainfallalongthePacificcoastofSouthAmericawasmuchhighe
7、rthannormal.NorthAmerica,Europe,andeastAsiasawhigherthannormaltemperatures.CaliforniawashardhitbyElNiñostormselsewhereintheworld,dryconditionsfostered(孕育)severeforestfiresandongoinghaze(雾霾)conditions.InPeru（秘鲁）,oneofthehardest-hitareas,torrentialrainshavetriggeredfloodsa
8、ndmudslides（泥石流）,washingawayhomes,farms,bridges,andhighways.FloodshaveevenuprootedacemeteryinTrujillo（特
