简介：Anewlightninglocatingtechnology,calledLightningMappingArray(LMA),hasbeendeveloped.ThesystemtakesadvantageofGPStechnologytomeasurethetimesofarrival(TOA)oflightningimpulsiveveryhighfrequency(VHF)radiationeventsateachremotelocation.Thespatiotemporaldevelopmentprocessesoflightningaredescribedinthree-dimensionbymeasurementofthesystemwithhightimeresolution(50ns)andspaceprecision(50-100m).Thechargestructuresinthunderstormandtheirrelationshipwithlightningdischargeprocessesarerevealed.Thetemporalandspatialcharacteristicsofpreliminarybreakdownprocessinvolvedinnegativecloud-to-ground(CG)lightningdischargesareanalyzedbasedonthedataoflightningVHFradiationevents.TheeffectofpositivechargeregioninlowerpartofthunderstormontheoccurrenceofnegativeCGlightningdischargeisdiscussed.TheresultsindicatethatthepreliminarybreakdownprocesswithlongerdurationinnegativeCGlightningdischargesisanintraclouddischargeprocess.Itoccursbetweennegativeandpositivechargeregionslocatedinmiddleandlowerpartsofthunderstormrespectively.Itinitiatesfromthenegativechargeregionandpropagatesdownward.Afterpropagatingintothepositivechargeregion,thelightningchanneldevelopshorizontally.Thecharacteristicsofthepreliminarybreakdownprocessareconsistentwiththatofintracloudlightningdischarges.ThesteppedleadersareinitiatedbytheKtypebreakdownwhichoccursinthelaststageofthepreliminarybreakdownprocessanddevelopsdownwardthroughthepositivechargeregion.TheexistenceofpositivechargeregioninlowerpartofthunderstormresultsintheoccurrenceofpreliminarybreakdownprocesswithlongerdurationbeforethereturnstrokeofnegativeCGlightningdischarges.