The eastern edge of the western Pacific warm pool （WPWP） in the upper layer （shallower than 50m） exhibits significant zonal displacements on interannual scale. Employing an intermediate ocean model, the dynamic me...The eastern edge of the western Pacific warm pool （WPWP） in the upper layer （shallower than 50m） exhibits significant zonal displacements on interannual scale. Employing an intermediate ocean model, the dynamic mechanism for the interannual zonal displacement of the WPWP eastern edge in the upper layer is investigated by diagnosing the dynamic impacts of zonal current anomalies induced by wind, waves （Kelvin and Rossby waves）, and their boundary reflections. The interannual zonal displacements of the WPWP eastern edge in the upper layer and the zonal current anomaly in the equatorial Pacific west of ll0~W for more than 30 years can be well simulated. The modeling results show that zonal current anomalies in the central and eastern equatorial Pacific are the dominant dynamic mechanism for the zonal displacements of the eastern edge of the upper WPWP warm water. Composite analyses suggest that the zonal current anomalies induced by waves dominate the zonal displacement of the WPWP eastern edge, whereas the role played by zonal wind-driven current anomalies is very small. A sensitivity test proves that the zonal current anomalies associated with reflected waves on the western and eastern Pacific boundaries can act as a restoring force that results in the interannual reciprocating zonal motion of the WPWP eastern edge.展开更多
Ocean current data for nearly 3 months in the South China Sea(SCS),combined with the NCEP/NCAR reanalysis wind data,are analyzed.The results indicate that the wind en-ergy enters the upper mixed layer in a wide contin...Ocean current data for nearly 3 months in the South China Sea(SCS),combined with the NCEP/NCAR reanalysis wind data,are analyzed.The results indicate that the wind en-ergy enters the upper mixed layer in a wide continuous frequency band.In addition,the interac-tion between the low-frequency wind anomaly and the low-frequency current anomaly is the most‘effective’way for the energy input from the wind to the upper ocean.However,only the inertial and the near inertial energy propagate downwards through the upper mixed layer.The down-ward-propagating energy is distributed into the barotropic currents,the baroclinic currents and each mode of the baroclinic currents following the normal distributions.The energy change ratios between the barotropic motion to the baroclinic motion induced by the wind present a normal distribution of N(0.0242,0.3947).The energy change ratios of the first 4 baroclinic modes to the whole baroclinic currents also follow the normal distributions.The first baroclinic mode follows N(0.2628,0.1872),the second N(0.1979,0.1504),the third N(0.1331,0.1633),and the fourth N(0.0650,0.1540),respectively.展开更多
基金Supported by the National Basic Research Program of China (No. 2006CB403606)the National Special Project: Chinese Offshore Investigation and Assessment (Nos. 908-02-01-02, 908-ZC-I-13)+1 种基金the Open Fund of State Key Laboratory of Satellite Ocean Environment Dynamics (No. 200601)the Scientific Research Foundation of Third Institute of Oceanography, SOA (No. 2009003)
文摘The eastern edge of the western Pacific warm pool （WPWP） in the upper layer （shallower than 50m） exhibits significant zonal displacements on interannual scale. Employing an intermediate ocean model, the dynamic mechanism for the interannual zonal displacement of the WPWP eastern edge in the upper layer is investigated by diagnosing the dynamic impacts of zonal current anomalies induced by wind, waves （Kelvin and Rossby waves）, and their boundary reflections. The interannual zonal displacements of the WPWP eastern edge in the upper layer and the zonal current anomaly in the equatorial Pacific west of ll0~W for more than 30 years can be well simulated. The modeling results show that zonal current anomalies in the central and eastern equatorial Pacific are the dominant dynamic mechanism for the zonal displacements of the eastern edge of the upper WPWP warm water. Composite analyses suggest that the zonal current anomalies induced by waves dominate the zonal displacement of the WPWP eastern edge, whereas the role played by zonal wind-driven current anomalies is very small. A sensitivity test proves that the zonal current anomalies associated with reflected waves on the western and eastern Pacific boundaries can act as a restoring force that results in the interannual reciprocating zonal motion of the WPWP eastern edge.
基金supported by theDepartment of Science and Technology of China(Grant No.TG1999043800).
文摘Ocean current data for nearly 3 months in the South China Sea(SCS),combined with the NCEP/NCAR reanalysis wind data,are analyzed.The results indicate that the wind en-ergy enters the upper mixed layer in a wide continuous frequency band.In addition,the interac-tion between the low-frequency wind anomaly and the low-frequency current anomaly is the most‘effective’way for the energy input from the wind to the upper ocean.However,only the inertial and the near inertial energy propagate downwards through the upper mixed layer.The down-ward-propagating energy is distributed into the barotropic currents,the baroclinic currents and each mode of the baroclinic currents following the normal distributions.The energy change ratios between the barotropic motion to the baroclinic motion induced by the wind present a normal distribution of N(0.0242,0.3947).The energy change ratios of the first 4 baroclinic modes to the whole baroclinic currents also follow the normal distributions.The first baroclinic mode follows N(0.2628,0.1872),the second N(0.1979,0.1504),the third N(0.1331,0.1633),and the fourth N(0.0650,0.1540),respectively.
