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简介：Landscapeconnectivityisimportantforenergyandmaterialflowinecosystemsaswellasforthesurvivalofspecies.Thelandscapestructureinfluencesandreflectsthedegreeoflandscapeconnectivity.Inordertostudythecouplingrelationshipbetweenlandscapestructureandconnectivityandrevealthesuccessionrelationshipbetweenitsstructureandconnectivityinthetypicalkarstplateauarea.ThestudyanalyzedthetypicalareaofHouzhaiRiverinPudingCounty,AnshunCity,GuizhouProvince,accordingtothelandscapepatternindexandprobabilitylandscapeconnectivityindex.Theresultsshow:(1)ThelandscapestructureofthestudyareaAismainlycharacterizedbylargepatchesanduniformdistribution.Themainlandiswoodlandandcultivatedland,andtheoveralllandscapeislowfragmentation.(2)ThelandscapestructureofthestudyareaBismainlycharacterizedbytheclusteringofacertaintypeoflandcoverandtheunevendistributionofthepatches,forexample,cultivatedland.Othertypesofpatchesarescatteredlydistributed,andtheoveralllandscapeishighlyfragmented.(3)ThestudyareaA,Bin100,500,1000,2000,3000,5distancethresholdsoflandscapeconnectivitywere1.55,1.99,2.26,2.49,2.58and0.02,0.10,0.15,0.19,0.20,respectively.Theaveragelandscapeconnectivityis2.18and0.13,respectively.StudyAreaAhasahigherdegreeoflandscapeconnectivitythanB.Landscapepatternindicatorscanrepresentthelandscapestructureandprobabilitylandscapeconnectivityindexcalculatesthelandscapeconnectivityinthestudyarea.Theresultsofthestudycanprovideabasisforecologicalrestorationofplateaukarstregionsandwell-orientedruraldevelopmentplanning.

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简介：ThisstudyinvestigatesclassificationanddiurnalvariationsoftheprecipitationechoesoverthecentralTibetanPlateaubasedontheobservationscollectedfromaC-bandvertically-pointingfrequency-modulatedcontinuous-wave(C-FMCW)radarduringtheThirdTibetanPlateauAtmosphericScientificExperiment(TIPEX-Ⅲ)2014-IntensiveObservationPeriod(2014-IOP).Theresultsshowthat51.32%oftheverticalprofileshavevalidechoeswithreflectivity>-10dBZ,and35.06%ofthevalidechoprofilesproduceprecipitationattheground(precipitationprofiles);stratiformprecipitationwithanevidentbright-bandsignature,weakconvectiveprecipitation,andstrongconvectiveprecipitationaccountfor52.03%,42.98%,and4.99%oftheprecipitationprofiles,respectively.About59.84%oftheprecipitationoccursintheafternoontomidnight,while40.16%oftheprecipitationwithweakerintensityisobservedinthenocturnalhoursandinthemorning.Diurnalvariationofoccurrencefrequencyofprecipitationshowsamajorpeakduring2100-2200LST(localsolartime)with59.02%beingthestratiformprecipitation;thesecondarypeakappearsduring1300-1400LSTwith59.71%beingtheweakconvectiveprecipitation;thestrongconvectiveprecipitationoccursmostly(81.83%)intheafternoonandeveningwithtwopeaksover1200-1300and1700-1800LST,respectively.Startingfromapproximately1100LST,precipitationechoesdevelopwithenhancedverticalairmotion,elevatedechotop,andincreasingradarreflectivity.Intenseupwardairmotionoccursmostfrequentlyin1700-1800LSTwithasecondarypeakin1100-1400LST,whilethetopsofprecipitationechoesandintenseupwardairmotionreachtheirhighestlevelsduring1600-1800LST.Theatmosphericconditionsintheearlymorningaredisadvantageousforconvectiveinitiationanddevelopment.Aroundnoon,theconvectiveavailablepotentialenergy(CAPE)increasesmarkedly,convectiveinhibition(CIN)isgenerallysmall,andasuper-dry-adiabaticlayerispresentnear