Seamounts affect the surrounding physical oceanography and form unique dynamic processes.The influences of these processes on biological and sedimentary distributions are quite different in seamount areas at different depths.The Y3 seamount is located in the Yap Arc of the tropical Western Pacific Ocean.The water depth of its summit is～280 m.Based on field data obtained in December 2014 and other open-access data,the physical oceanography around the Y3 seamount was preliminarily analyzed.The results show that the upper layer(0-150 m)was under the influence of the westward-flowing North Equatorial Current(NEC),while the eastward-flowing North Equatorial Undercurrent(NEUC)controlled the water between 200-800 m.The NEC was strong and steady,but the NEUC was disturbed by the Y3 seamount.The cold dome above the Y3 seamount was not caused by a Taylor cap or tidal rectification but probably by upwelling during the survey time.Tidal currents were squeezed against topography and greatly amplified in the Y3 seamount.The thicknesses of the surface turbulent layers were greatly influenced by the spring-neap tidal cycle.The turbulent diffusivities in the sea surface layer above the Y3 seamount were much larger than those in the open ocean.Calculations showed that the surface wind stress greatly affected the turbulent mixing in the surface layer of the Y3 seamount.The reciprocal action between the amplified tidal currents and topography was the most likely cause of the turbulent mixing near the bottom of the Y3 seamount.This study can provide a scientific basis for further study of biological and depositional characteristics at the Y3 seamount.

Zhenyan WANG;Xingyu SHI;Haijun HUANG

CAS Key Laboratory of Marine Geology and Environment,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China;Laboratory for Marine Mineral Resources,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266071,China;University of Chinese Academy of Sciences,Beijing 100049,China;Center for Ocean Mega-Science,Chinese Academy of Sciences,Qingdao 266071,China

海洋湖沼学报（英文版）

[1]Zhenyan WANG;Xingyu SHI;Haijun HUANG-.Observation of physical oceanography at the Y3 seamount(Yap Arc)in winter 2014)[J].海洋湖沼学报（英文版）,2022(04):1314-1332

Seamounts,Undercurrent,NEUC

Observation,physical,oceanography,Y3,seamount,Yap,Arc,winter,surrounding,form,unique,dynamic,processes,influences,these,biological,sedimentary,distributions,quite,different,areas,depths,located,tropical,Pacific,Ocean,water,its,summit,Based,field,data,obtained,December,other,open,access,around,was,preliminarily,analyzed,results,that,upper,under,westward,flowing,North,Equatorial,Current,NEC,while,eastward,controlled,between,strong,steady,disturbed,by,cold,dome,above,not,caused,Taylor,cap,tidal,rectification,probably,upwelling,during,survey,Tidal,currents,were,squeezed,against,topography,greatly,amplified,thicknesses,surface,turbulent,layers,influenced,spring,neap,cycle,diffusivities,much,larger,than,those,Calculations,showed,wind,stress,affected,mixing,reciprocal,action,most,likely,near,bottom,This,study,can,provide,scientific,basis,further,depositional,characteristics

0.480199