INFLUENCE OF TROPICAL CYCLOGENESIS AND EQUATORIAL WESTERLY ZONE ON THE DEVELOPMENT OF SEA SURFACE TEMPERATURE ANOMALIES IN THE EQUATORIAL PACIFIC

E. K. Semenov, E. V. Sokolikhina, and N. N. Sokolikhina

Using the method of a singular value decomposition of the covariance matrix, the relationship between the atmospheric circulation regime and the dynamics of developing equatorial Pacific sea surface temperatures (SST) is estimated. It is established that at the level of synoptic-scale processes the first signal related to the southeasterly trade weakening comes from the atmosphere seven months before the SST anomalies development. The second, stronger signal related to activation of tropical cyclogenesis and equatorial westerly zone formation at the center of the ocean, comes four months before the SST anomalies. This is in accord with the real pattern of the 1982-1983 El Nino development. It is shown that unlike the usual correlation analysis, the singular decomposition method allows one to separate the two processes, namely, the seasonal variability and the SST and zonal wind anomalies, which made it possible to determine the atmosphere-ocean relation within these processes.