Model Study of the Equatorial Ocean Surface Temperature Response to Wind Forcing during El Nino

摘要

This thesis investigated processes that contribute to large scale equatorial SST variability, and by comparison with observation, verify the realism of the model's thermal response to prescribed forcing in the atmosphere. More realistic thermodynamic processes are incorporated in the ocean part of Rennick's (1985) coupled ocean-atmosphere model and an examination of its response to prescribed wind forcing is conducted. The dynamic ocean model is based on the shallow water momentum equations forced by a surface wind stress. It is linearized about a motionless state with a zonally sloping pycnocline depth which is in balance with the surface stress caused by the zonal wind of the atmospheric basic state. This study investigates the effect of turbulent vertical mixing of heat, in contrast to horizontal advection, for the generation of SST anomalies in the equatorial region of the Pacific. Results showed that the SST anomaly produced by turbulent mixing was two orders of magnitude smaller than, and 90 deg out of phase with, the SST anomaly generated by horizontal advection.