Dynamic mechanism of interannual zonal displacements of the eastern edge of the western Pacific warm pool
QI Qinghua , ZHANG Qilong , HOU Yijun Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China Graduate University of Chinese Academy of Sciences, Beijing 100039, China State Key Laboratory of Satellite Ocean Environment Dynamics, the Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China Key Laboratory of Global Change and Marine-Atmospheric Chemistry, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China
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 110°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.
【Fund】： 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);; 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)
【CateGory Index】： P732
【CateGory Index】： P732