有关美国地理的英语文章

TheUnitedStatesistheworld'sthirdorfourthlargestnationbytotalarea,beforeorafterthePeople'sRepublicofChina,dependingonhowtwoterritoriesdisputedbyChinaandIndiaarecounted.Includingonlylandarea,theUnitedStatesisthirdinsizebehindRussiaandChina,justaheadofCanada.ThecontinentalUnitedStatesstretchesfromtheAtlanticOceantothePacificOceanandfromCanadatoMexicoandtheGulfofMexico.Alaskaisthelargeststateinarea.SeparatedbyCanada,ittouchesthePacificandArcticOceans.HawaiioccupiesanarchipelagointhePacific,southwestofNorthAmerica.ThecommonwealthofPuertoRico,thelargestandmostpopulousU.S.territory,isinthenortheasternCaribbean.Withafewexceptions,suchastheterritoryofGuamandthewesternmostportionsofAlaska,nearlyallofthecountryliesinthewesternhemisphere.

ThecoastalplainoftheAtlanticseaboardgiveswayfurtherinlandtodeciduousforestsandtherollinghillsofthePiedmont.TheAppalachianMountainsdividetheeasternseaboardfromtheGreatLakesandthegrasslandsoftheMidwest.TheMississippi-MissouriRiver,theworld'sfourthlongestriversystem,runsmainlynorth-souththroughtheheartofthecountry.Theflat,fertileprairielandoftheGreatPlainsstretchestothewest.TheRockyMountains,atthewesternedgeoftheGreatPlains,extendnorthtosouthacrossthecontinentalUnitedStates,reachingaltitudeshigherthan14,000feet(4,300m)inColorado.TheareatothewestoftheRockiesisdominatedbydesertssuchastheMojaveandtherockyGreatBasin.TheSierraNevadarangerunsparalleltotheRockies,relativelyclosetothePacificcoast.At20,320ft(6,194m),Alaska'sMountMcKinleyisthecountry'stallestpeak.ActivevolcanoesarecommonthroughouttheAlexanderandAleutianIslandsandtheentirestateofHawaiiisbuiltupontropicalvolcanicislands.ThesupervolcanounderlyingYellowstoneNationalParkintheRockiesisthecontinent'slargestvolcanicfeature.

BecauseoftheUnitedStates'largesizeandwiderangeofgeographicfeatures,nearlyeverytypeofclimateisrepresented.Theclimateistemperateinmostareas,tropicalinHawaiiandsouthernFlorida,polarinAlaska,semiaridintheGreatPlainswestofthe100thmeridian,desertintheSouthwest,MediterraneanincoastalCalifornia,andaridintheGreatBasin.Extremeweatherisnotuncommon—thestatesborderingtheGulfofMexicoarepronetohurricanesandmostoftheworld'stornadoesoccurwithinthecontinentalUnitedStates.