The eastward-propagation phenomenon from GPS-tracking drifters is characterized by strong Wyrtki Jets（WJs）,with a maximum velocity of over 1.3 m s^（-1）.Based on data gathered during a 2014 spring sea cruise in the...The eastward-propagation phenomenon from GPS-tracking drifters is characterized by strong Wyrtki Jets（WJs）,with a maximum velocity of over 1.3 m s^（-1）.Based on data gathered during a 2014 spring sea cruise in the Indian Ocean,the trajectories show the WJs bifurcate at the equator near the eastern boundary and flow northward and southward in two narrow strong currents.Surface currents reverse and flow westward in the east of the bifurcation longitude.In addition,Aquarius satellite data show the high-salinity water flows eastward from the western Indian Ocean,associated with WJs.Salinity budget analyses in the mixed layer using salinity data from Argo and currents data from OSCAR indicate that the WJs do indeed transport the high-salinity water eastward at the equator,and WJs bifurcation transports high-salinity water away from the equator and suppresses the Bay of Bengal and Java coast from freshening.Therefore,the WJs and WJs bifurcation play an important role in maintaining the salinity balance in the eastern Indian Ocean.展开更多
Features of the interannual variability of the spring Wyrtki Jet in the tropical Indian Ocean are revealed using observation data and model output.The results show that the jet has signifi cant interannual variation,w...Features of the interannual variability of the spring Wyrtki Jet in the tropical Indian Ocean are revealed using observation data and model output.The results show that the jet has signifi cant interannual variation,which has a signifi cant correlation with winter El Niño Modoki index(R=0.62).During spring after an El Niño(La Niña)Modoki event,the Wyrtki Jet has a positive(negative)anomaly,forced by a westerly(easterly)wind anomaly.The result of a linear-continuously stratifi ed model shows that the fi rst two baroclinic modes explain most of the interannual variability of the spring Wyrtki Jet(~70%)and the third to fi fth modes together account for approximately 30%.Surface wind anomalies in the tropical Indian Ocean are related to the Walker circulation anomaly associated with El Niño/La Niña Modoki.The interannual variability of the spring Wyrtki Jet has an evident impact on sea surface salinity transport before the onset phase of the summer monsoon in the Indian Ocean.展开更多
A strong spring Wyrtki jet(WJ)presents in May 2013 in the eastern equatorial Indian Ocean.The entire buildup and retreat processes of the spring WJ were well captured by two adjacent Acoustic Doppler Current Profilers...A strong spring Wyrtki jet(WJ)presents in May 2013 in the eastern equatorial Indian Ocean.The entire buildup and retreat processes of the spring WJ were well captured by two adjacent Acoustic Doppler Current Profilers mounted on the mooring systems.The observed zonal jet behaved as one intraseasonal event with the significant features of abrupt emergence as well as slow disappearance.Further research illustrate that the pronounced surface westerly wind burst during late-April to mid-May,associated with the active phase of a robust eastwardpropagating Madden–Julian oscillation in the tropical Indian Ocean,was the dominant reason for the rapid acceleration of surface WJ.In contrasting,the governing mechanism for the jet termination was equatorial wave dynamics rather than wind forcing.The decomposition analysis of equatorial waves and the corresponding changes in the ocean thermocline demonstrated that strong WJ was produced rapidly by the wind-generated oceanic downwelling equatorial Kelvin wave and was terminated subsequently by the westward-propagating equatorial Rossby wave reflecting from eastern boundaries of the Indian Ocean.展开更多
The basic structure and intraseasonal evolution of currents in the southeastern Andaman Sea was analyzed based on data collected in 2017 from two subsurface moorings(C1 and C5).Periodic variation in the upper ocean cu...The basic structure and intraseasonal evolution of currents in the southeastern Andaman Sea was analyzed based on data collected in 2017 from two subsurface moorings(C1 and C5).Periodic variation in the upper ocean currents of the Andaman Sea was investigated by combining observational and satellite data.Mooring observations show that rapid changes of current speed and direction occurred in May and June,with a significant increase in current velocity at the C1 mooring.In the second half of the year,southward flow dominated at the C1 mooring,and alternating northward and southward flows were evident at the C5 mooring during the same period but the northward flow prevailed in boreal winter.In addition,analysis of the power spectra of the upper currents revealed that the tidal period at both moorings is primarily semidiurnal with weaker energy than that of the low-frequency currents.The upper ocean currents at the C1 and C5 moorings exhibited intraseasonal variation of 30-60 d and 120 d,while the zonal current at the C1 mooring exhibited a notable period of approximately 180 d.Further analysis indicated that the variability of currents in the Andaman Sea is influenced primarily by equatorial Kelvin waves and Rossby wave packets.Moreover,our results suggest that equatorial Kelvin waves from the eastern Indian Ocean entered the Andaman Sea in the form of Wyrtki Jets and propagated primarily along two distinct pathways during the observation period.In addition to coastal boundary Kelvin waves,it was found that a branch of the Wyrtki Jet that directly enters the Andaman Sea and flows northward along the slope of the continental shelf,and reflected Rossby wave packets by topography.展开更多
基金supported by the National Natural Science Foundation of China(NSFC)[grant numbers 41206018 and41176019]the National Basic Research Program of China[grant number 2012CB956001]+2 种基金the National Program on Global Change and Air-Sea Interaction of the China Meteorological Administration[grant number GYHY201306018]the Strategic Priority Project of Chinese Academy of Sciences[grant numbers XDA11010203]the NSFC-Shandong Joint Fund for Marine Science Research Centers[grant number U1406401]
文摘The eastward-propagation phenomenon from GPS-tracking drifters is characterized by strong Wyrtki Jets（WJs）,with a maximum velocity of over 1.3 m s^（-1）.Based on data gathered during a 2014 spring sea cruise in the Indian Ocean,the trajectories show the WJs bifurcate at the equator near the eastern boundary and flow northward and southward in two narrow strong currents.Surface currents reverse and flow westward in the east of the bifurcation longitude.In addition,Aquarius satellite data show the high-salinity water flows eastward from the western Indian Ocean,associated with WJs.Salinity budget analyses in the mixed layer using salinity data from Argo and currents data from OSCAR indicate that the WJs do indeed transport the high-salinity water eastward at the equator,and WJs bifurcation transports high-salinity water away from the equator and suppresses the Bay of Bengal and Java coast from freshening.Therefore,the WJs and WJs bifurcation play an important role in maintaining the salinity balance in the eastern Indian Ocean.
基金Supported by the National Key R&D Program of China(No.2018YFA0605702)the National Natural Science Foundation of China(Nos.41876002,41776002)the Fundamental Research Funds for the Central Universities(Nos.2017B04714,2017B04114)。
文摘Features of the interannual variability of the spring Wyrtki Jet in the tropical Indian Ocean are revealed using observation data and model output.The results show that the jet has signifi cant interannual variation,which has a signifi cant correlation with winter El Niño Modoki index(R=0.62).During spring after an El Niño(La Niña)Modoki event,the Wyrtki Jet has a positive(negative)anomaly,forced by a westerly(easterly)wind anomaly.The result of a linear-continuously stratifi ed model shows that the fi rst two baroclinic modes explain most of the interannual variability of the spring Wyrtki Jet(~70%)and the third to fi fth modes together account for approximately 30%.Surface wind anomalies in the tropical Indian Ocean are related to the Walker circulation anomaly associated with El Niño/La Niña Modoki.The interannual variability of the spring Wyrtki Jet has an evident impact on sea surface salinity transport before the onset phase of the summer monsoon in the Indian Ocean.
基金The Basic Scientific Fund for National Public Research Institutes of China under contract Nos 2019Q03 and 2017S02the National Natural Science Foundation of China under contract Nos 41706032,41406012,4187060841,41876028 and 41676020+3 种基金Taishan Scholars Programs of Shandong Province under contract No.tsqn201909165the National Program on Global Change and Air-Sea Interaction under contract Nos GASI-IPOVAI-03,GASI-IPOVAI-02,GASI-02-IND-STSaut and GASI-02-IND-STSwinthe NSFC-Shandong Joint Fund for Marine Science Research Centers under contract No.U1606405the Ao-Shan Talents Cultivation Program supported by Pilot National Laboratory for Marine Science and Technology(Qingdao)under contract No.2017ASTCP-OS01。
文摘A strong spring Wyrtki jet(WJ)presents in May 2013 in the eastern equatorial Indian Ocean.The entire buildup and retreat processes of the spring WJ were well captured by two adjacent Acoustic Doppler Current Profilers mounted on the mooring systems.The observed zonal jet behaved as one intraseasonal event with the significant features of abrupt emergence as well as slow disappearance.Further research illustrate that the pronounced surface westerly wind burst during late-April to mid-May,associated with the active phase of a robust eastwardpropagating Madden–Julian oscillation in the tropical Indian Ocean,was the dominant reason for the rapid acceleration of surface WJ.In contrasting,the governing mechanism for the jet termination was equatorial wave dynamics rather than wind forcing.The decomposition analysis of equatorial waves and the corresponding changes in the ocean thermocline demonstrated that strong WJ was produced rapidly by the wind-generated oceanic downwelling equatorial Kelvin wave and was terminated subsequently by the westward-propagating equatorial Rossby wave reflecting from eastern boundaries of the Indian Ocean.
基金Supported by the Laoshan Laboratory(No.LSK 202203003)the National Key R&D Program of China(No.2022YFC3104100)。
文摘The basic structure and intraseasonal evolution of currents in the southeastern Andaman Sea was analyzed based on data collected in 2017 from two subsurface moorings(C1 and C5).Periodic variation in the upper ocean currents of the Andaman Sea was investigated by combining observational and satellite data.Mooring observations show that rapid changes of current speed and direction occurred in May and June,with a significant increase in current velocity at the C1 mooring.In the second half of the year,southward flow dominated at the C1 mooring,and alternating northward and southward flows were evident at the C5 mooring during the same period but the northward flow prevailed in boreal winter.In addition,analysis of the power spectra of the upper currents revealed that the tidal period at both moorings is primarily semidiurnal with weaker energy than that of the low-frequency currents.The upper ocean currents at the C1 and C5 moorings exhibited intraseasonal variation of 30-60 d and 120 d,while the zonal current at the C1 mooring exhibited a notable period of approximately 180 d.Further analysis indicated that the variability of currents in the Andaman Sea is influenced primarily by equatorial Kelvin waves and Rossby wave packets.Moreover,our results suggest that equatorial Kelvin waves from the eastern Indian Ocean entered the Andaman Sea in the form of Wyrtki Jets and propagated primarily along two distinct pathways during the observation period.In addition to coastal boundary Kelvin waves,it was found that a branch of the Wyrtki Jet that directly enters the Andaman Sea and flows northward along the slope of the continental shelf,and reflected Rossby wave packets by topography.
