简介:TheNCEP/NCARreanalysisdatahavebeenemployedtodiagnosevariationsofthezonalmeanflowinborealsummer.TwoleadingEOFmodesarefoundtodominatethespatialandtemporalchangesofthesummertimezonalmeanwindsinthetroposphere.EOF1showsthedistributionofzonal-meanflowanomalieswithhighervarianceintheNorthPolarRegion,whereastheEOF2showsthedistributionofzonal-meanflowanomalieswithhighervarianceintropicalandextra-tropicalregions.TheEOF1andEOF2haverespectivelytheperiodicitiessimilartothoseofAOandENSO.SignificantlagcorrelationshavebeenfoundbetweenEOF1andENSO,andbetweenEOF2andAO,intheseasonsincludingspring,autumn,andwinter.However,nosignificantcorrelationshavebeenfoundbetweenEOF1insummerandENSOinanyotherseasons,andbetweenEOF2insummerandAOinotherseasons,nomatterhowbigthelagthatrepresentsnumberofseasonshasbeenset.Theseresultssuggestthattheprincipalmodesofsummertimezonalmeanflowcouldbestatisticallyseparatedfromeachother.Hence,EOF1andEOF2arephysicallyrelatedtotheAOandENSOrespectively.Atheorycalledquasi-geostrophicnon-accelerationtheoremhasbeenusedtopartlyexplainthepossiblemechanismsofthemaintenanceofthetwoprincipalmodes.ThecompositedifferencesofthedivergenceofEliassen-Palmflux(E-Pflux)betweenpositiveandnegativeyearsasobtainedfromthetimeseriesofEOF1andEOF2displaythedistributionsthatcontributetothezonalmeanwindanomaliesrepresentedbyEOF1andEOF2,respectively.TheplanetaryotherthanthesynopticwavesdominatethebehaviorsoftheE-Pfluxes,suggestingthecrucialroleoftheplanetarywavesinthemaintenanceofthezonalmeanflowanomalies.Theresidualcirculationaswellasthefriction,whichcancelthedivergenceoftheE-Pflux,alsoplayanimportantroleinsomeplaces.TheseresultsareveryhelpfulforourbetterunderstandinghowtheanomalouszonalmeanflowsmaintainandhowtheENSOandAOinfluencetheglo
简介:Ninesamplesofsuspendedmatteratthesurfaceorbottomand34elementsin20samplesofsubstratesedimenthavebeenusedintheneutronactivationanalyses.Authorsstudysedimentandsuspendedmattermovementbyusingthemethodofelementgeochemistry,andconcludethroughsyntheticanalysisandprocessingthatthemovementdirectionofsuspendedmatterandsubstratesedimenttendstoconvergeonthecentralarea.
简介:摘要:随着国家建设的不断发展,人们对建筑行业的不断创新,要求的质量更高,速度更快,施工更安全。在基坑施工阶段,深基坑开挖是一项复杂且难度高,未知数更多的工程,合理的基坑支护方式不但会大大降低施工难度,而且更高效,更安全。
简介:摘要:文章通过介绍钢板加固圆管涵的施工过程,阐述钢板加固圆管涵的施工工艺与注意要点,旨在为相关工程提供指导,确保加固施工的顺利进行和达到预期的效果。