简介:WhiletheAntarcticSlopeCurrent(ASC)hasbeenintensivelystudiedfortheEastAntarcticaslopeareaandtheWeddellSea,itsfateinthewesternAntarcticPeninsula(WAP)regionremainsmuchlessknown.DatafromtwocruisesconductedneartheSouthShetlandIslands(SSIs)andtheElephantIsland(EI),oneinaustralsummerof2004andoneinaustralwinterof2006,wereanalyzedtoprovideabroadpictureofthecirculationpatternoverthecontinentalslopeofthesurveyedarea,andaninsightintothedynamicalbalanceofthecirculation.Theresultsindicatethatsouthwestwardcurrentsarepresentovertheupperslopeinthestudyarea,indicatingtheASCintheWAPregion.NeartheShackletonGap(SG)northoftheEI,thesouthwestwardslopecurrentsneartheshelfbreakarecharacterizedbyawatermasscolderandfresherthantheambientwater,whichproducescross-slopedensitygradientsandthenverticalshearofthealong-slope(oralong-isobath)velocity.Theverticalshearisassociatedwithareversalofthealong-slopecurrentfromnortheastwardatsurfacetosouthwestwardindeeperlayers,oradepth-intensificationofthesouthwestwardslopecurrents.ThewatermasswithtemperatureandsalinitycharacteristicssimilartotheobservedcoldandfreshwaterisalsorevealedonthesouthernslopeoftheScotiaSea,suggestingthatthiscoldandfreshwaterisoriginatedfromtheScotiaSeaslopeandflowssouthwestwardthroughtheSG.OvertheshelfnorthoftheSSIs,thecoldandfreshwatermassisalsoobservedandoriginatesmainlyfromtheBransfieldStrait.Inthisarea,verticalstructureofthesouthwestwardslopecurrentsisassociatedwiththeonshoreintrusionoftheupperCircumpolarDeepWaterthatcreatescross-slopedensitygradients.