热带外太平洋通过海洋过程对热带太平洋的影响

利用MOM2海洋环流模式分别研究了年际和年代际尺度上热带外太平洋通过海洋过程对热带太平洋的影响.利用1945~1993年COADS资料的表面通量强迫海洋模式,积分46 a作为模式控制试验.取热带外太平洋海表面强迫为气候值做敏感性试验.将控制试验结果减去敏感性结果就可以得到热带外太平洋通过海洋过程对热带太平洋的影响.结果表明,年际尺度上,主要是海洋波动过程起作用,但总的海洋过程的影响较小.年代际尺度上,主要是副热带环流输送起作用,其中包括平均环流输送的温度异常以及异常环流输送的平均温度,并且后者贡献相对较大.年际和年代际尺度上,热带太平洋的温度异常主要发生在密度跃层附近.研究发现热带外南太平洋对热带和热带外太平洋之间的水量交换有影响,而热带外北太平洋的影响较弱.

Influence of the extratropical Pacific on the tropical Pacific through oceanic processes

The influence of the extratropical Pacific on the tropical Pacific through the oceanic processes on the interannual and interdecadal time scales was studied with an oceanic general circulation model,the Modular Ocean Model version 2 of Geophysical Fluid Dynamics Laboratory.The model was run for 46 a(1945~1993) with the surface conditions taken from COADS,as a control run.A parallel sensitivity experiment was run with the same surface conditions everywhere as the control run except over the extratropical Pacific where the surface condition was prescribed with climatology.Difference between the control run and the sensitivity run indicates the influence of the extratropical Pacific on the tropical Pacific through the oceanic processes.On the interannual time scale,the process of wave propagation is important,but its influence is weak.On the interdecadal time scale,dominant process is associated with the thermal transportation of subtropical cell in which the transportation due to anomalous cell is more important than the climatological cell.The oceanic temperature anomaly is mainly located in pycnocline both on the interannual and interdecadal time scales.The surface forcing of the extratropical South Pacific has impact on water mass exchange between the extratropical and tropical Pacific,while such an impact is weak in the extratropical North Pacific.