Variational characteristics analyses of the El Niño event in 2009/2010

The variability of one warming event which occurred on the equatorial Pacific Ocean in the summer 2009/2010 was analyzed using the temperature and wind data from tropical atmosphere ocean (TAO) project dataset. The variation and propagation of anomalous subsurface ocean temperature in equatorial Pacific were discussed in the process of El Niño event. The results indicated that there were two different mechanisms in eastern equatorial Pacific warming process in the summer 2009/2010. One was the propagation of the anomalous subsurface ocean temperature along the thermocline from west to east Pacific and the local warming in eastern Pacific. The other was the increase of west wind in the western Pacific warm pool (WPWP) made the wind convergence. This convergence conduced to the warm water downwelling from surface to subsurface. Then the subsurface water was warm again and eastward propagated. These results indicated that the anomalous temperature from the subsurface signal cycle in the tropical Pacific, the local warming in the eastern equatorial Pacific due to the decrease of wind and the atmosphere forcing in WPWP were the main reasons which induced the warmer event in 2009/2010.