简介：CART(Constituent-orientedageandresidencetimetheory)andPTM(Particle-trackingmethod)aretwowidelyusednumericalmethodstocalculatewaterage.Thesetwomethodsareessentiallyequivalentintheorybuttheirresultsmaybedifferentinpractice.Thedifferenceofthetwomethodswasevaluatedbyapplyingthemtocalculatewaterageinanidealizedone-dimensionaldomain.Themodelresultsbythetwomethodsareconsistentwitheachotherinthecasewitheitherspatiallyuniformflowfieldorspatiallyuniformdiffusioncoefficient.Ifweallowthespatialvariationinhorizontaldiffusion,atermcalledpseudodisplacementarisingfromthespatialvariationofdiffusioncoefficientlikelyplaysanimportantroleforthePTMtoobtainaccuratewaterage.Inparticular,ifthewaterparticleisreleasedataplacewherethediffusionisnottheweakest,thewateragecalculatedbythePTMwithoutpseudodisplacementismuchlargerthanthatbytheCART.ThissuggeststhatthepseudodisplacementcannotbeneglectedinthePTMtocalculatewaterageinarealisticocean.Asanexample,wepresentitspotentialimportanceintheBohaiSeawherethediffusioncoefficientvariesspatiallyandgreatly.

简介：Inthisstudy,changesinArcticseaicethicknessforeachiceagecategorywereexaminedbasedonsatelliteobservationsandmodelledresults.InterannualchangesobtainedfromIce,Cloud,andLandElevationSatellite(ICESat)-basedresultsshowathicknessreductionoverperennialseaice(icethatsurvivesatleastonemeltseasonwithanageofnolessthan2year)uptoapproximately0.5–1.0mand0.6–0.8m(dependingoniceage)duringtheinvestigatedwinterandautumnICESatperiods,respectively.Pan-ArcticIceOceanModelingandAssimilationSystem(PIOMAS)-basedresultsprovideaviewofacontinuedthicknessreductionoverthepastfourdecades.Comparedto1980s,thereisaclearthicknessdropofroughly0.50min2010sforperennialice.Thisoveralldecreaseinseaicethicknesscanbeinpartattributedtotheamplifiedwarmingclimateinnorthlatitudes.Besides,wefigureoutthatstronglyanomaloussoutherlysummersurfacewindsmayplayanimportantroleinpromptingthethicknessdeclineinperennialicezonethroughtransportingheatdepositedinopenwater(primarilyviaalbedofeedback)inEurasiansectordeepintoabroaderseaiceregimeincentralArcticOcean.Thisheatsourceisresponsibleforenhancedicebottommelting,leadingtofurtherreductioninicethickness.

简介：TheEastChinaSea(ECS)isariver-dominatedepicontinentalsea,linkingtheAsiancontinenttothenorthwesternPacificviathelargeriversoriginatingfromTibetanPlateau.TherelevanthugeinfluxofriverinedetritushasdevelopeduniquesedimentarysystemsintheECSduringtheQuaternary,offeringidealterrestrialarchivesforreconstructingQuaternarypaleoenvironmentalchangesandstudyingland-seainteractions.Overall,twocharacteristicriversystemsdominatethesedimentarysystemsandsedimentsourcetosinktransportpatternsintheECS,representedbytheChangjiang(YangtzeRiver)andHuanghe(YellowRiver)forthelargeriversystemandTaiwanriversforthesmallriversystem.Giventhis,thesedimentsderivedfrombothriversystemsbeardistinctfeaturesintermsofparentrocklithology,provenanceweatheringandsedimenttransport.Previousstudiesmostlyfocusoneitherthe‘source’discriminationorthe‘sink’recordsofthesedimentarysystemintheECS,whilethesourcetosinkprocesslinkingthelandandsea,inparticularitstimescale,hasbeenpoorlyunderstood.Hereweintroduceanewly-developeddatingtechnique,the‘comminutionage’method,whichoffersaquantitativeconstraintonthetimescaleofsedimenttransferfromitsultimatesourcetothefinaldepositionalsink.Thisnovelmethodisofgreatsignificanceforimprovingourunderstandingontheearthsurfaceprocessesincludingtectonic-climatedrivenweathering,andsedimentrecyclinginrelationtolandscapeevolutionandmarineenvironmentalchanges.TheapplicationofcomminutionagemethodintheECSwillprovideimportantconstraintsonsedimentsource-to-sinkprocessandmoreevidencesfortheconstructionoflateQuaternarypaleoenvironmentalchangesundertheseuniquesedimentarysystems.更多还原