澳大利亚地理概况

AustraliaContents•1.Physicalgeography•2.Politicalgeography•3.Climate•4.Naturalhazards•5.EnvironmentAustraliaisacountry,andacontinent.ItislocatedinOceaniabetweentheIndianOceanandtheSouthPacificOcean.Itisthesixthlargestcountryintheworldwithatotalareaof7,686,850squarekilometers(includingLordHoweIslandandMacquarieIsland),makingitslightlysmallerthanthe48statesofthecontiguousUnitedStatesand31.5timeslargerthantheUnitedKingdom.•TheAustralianmainlandhasatotalcoastlinelengthof35,876kmwithanadditional23,859kmofislandcoastlines.Thereare758estuariesaroundthecountrywithmostlocatedinthetropicalandsub-tropicalzones.•Australiahasthelargestareaofoceanjurisdictionofanycountryonearth.Ithasnolandborders.•Australiaisthelowest,flattest,andoldestcontinentallandmassonEarthandithashadarelativelystablegeologicalhistory.GeologicalforcessuchastectonicupliftofmountainrangesorclashesbetweentectonicplatesoccurredmainlyinAustralia'searlyhistory,whenitwasstillapartofGondwana.•ItshighestpeakisMountKosciuszkoat2,228metres,whichisrelativelylowincomparisontothehighestmountainsonothercontinents.ErosionhasheavilyweatheredAustralia'ssurface.•Australiaissituatedinthemiddleofthetectonicplate,andthereforecurrentlyhasnoactivevolcanism.Minorearthquakeswhichproducenodamageoccurregularly,whilemajorearthquakesmeasuringgreaterthanmagnitude6occuronaverageeveryfiveyears.Theterrainismostlylowplateauwithdeserts,rangelandsandafertileplaininthesoutheast.TheGreatBarrierReef,byfartheworld'slargestcoralreef,liesashortdistanceoffthenorth-eastcoast.ContinentsofAustraliaTheAustraliancontinentallandmassconsistsof6distinctlandformdivisions.•TheEasternHighlands—includingtheGreatDividingRange,thefertileBrigalowBeltstripofgrasslandbehindtheeastcoast,andtheEasternUplands•TheEasternalluvialPlainsandLowlands—MurrayDarlingbasincoverssouthernpart,alsoincludespartsoftheLakeEyreBasinandextendstotheGulfofCarpentaria•TheSouthAustralianHighlands—includingtheFlindersRange,EyrePeninsulaandYorkePeninsula•TheWesternPlateau—includingtheNullarborPlain•TheCentralDeserts•NorthernPlateauandBasins—includingtheTopEndTheHydrologyofAustralia•BecausemuchofAustralia'sinteriorisarid,thelowaverageannualrainfallmeansinteriorriversareoftendryandlakesempty.Theheadwatersofsomewaterwaysarelocatedintropicalregionswheresummerrainscreateahighrateofdischarge.FloodeventsdrasticallyalterthedryenvironmentinwhichtheecologyofcentralAustraliahashadtoadapttotheboomandbustcycle.•TheGreatArtesianBasinisanimportantsourceofwater,theworld'slargestanddeepestfreshwaterbasin.Accesstowaterfromthebasinhasledtotheexpansionofgrazingintoareasthatwerepreviouslyfartoodryforlivestock.•Townsandcitiesacrossthecountrysometimesfacemajorwaterstorageandusagecrisisinwhichrestrictionsandothermeasuresareimplementedtoreducewaterconsumption.Waterrestrictionsarebasedonagradientofactivitiesthatbecomeprogressivelybannedasthesituationworsens.Politicalgeography•Australiaconsistsofsixstates,twomajormainlandterritories,andotherminorterritories.ThestatesareNewSouthWales,Queensland,SouthAustralia,Tasmania,VictoriaandWesternAustralia.ThetwomajormainlandterritoriesaretheNorthernTerritoryandtheAustralianCapitalTerritory.WesternAustraliaisthelargeststatecoveringjustunderonethirdoftheAustralianlandmass,followedbyQueenslandandNewSouthWales.•Australiaalsohasseveralminorterritories;thefederalgovernmentadministersaseparateareawithinNewSouthWales,theJervisBayTerritory,asanavalbaseandseaportforthenationalcapital.InadditionAustraliahasthefollowing,inhabited,externalterritories:NorfolkIsland,ChristmasIsland,Cocos(Keeling)Islands,andseverallargelyuninhabitedexternalterritories:AshmoreandCartierIslands,CoralSeaIslands,HeardIslandandMcDonaldIslandsandtheAustralianAntarcticTerritory.•BillabongistheAustraliannamegiventotheoxbowlakesthatcanformalongameanderingriver'scourse.Inaworld-widecomparisonofheight,Australia'swaterfallsarerelativelyinsignificant,withthelongestdropranked135thaccordingtotheWorldWaterfallDatabase.Climate•ByfarthelargestpartofAustraliaisaridorsemi-arid.Atotalof18%ofAustralia'smainlandconsistsofnameddeserts,[8]whileadditionalareasareconsideredtohaveadesertclimatebasedonlowrainfallandhightemperature.Onlythesouth-eastandsouth-westcornershaveatemperateclimateandmoderatelyfertilesoil.Thenorthernpartofthecountryhasatropicalclimate:partistropicalrainforests,partgrasslands,andpartdesert.•Rainfallishighlyvariable,withfrequentdroughtslastingseveralseasonsthoughttobecausedinpartbytheElNiño-SouthernOscillation.Occasionallyaduststormwillblanketaregionorevenseveralstatesandtherearereportsoftheoccasionallargetornado.Risinglevelsofsalinityanddesertificationinsomeareasisravagingthelandscape.•Australia'stropical/subtropicallocationandcoldwatersoffthewesterncoastmakemostofwesternAustraliaahotdesertwitharidity,amarkedfeatureofthegreaterpartofthecontinent.Thesecoldwatersproducelittlemoistureneededonthemainland.•A2005studybyAustralianandAmericanresearchersinvestigatedthedesertificationoftheinterior,andsuggestedthatoneexplanationwasrelatedtohumansettlerswhoarrivedabout50,0