The ENSO Events in the Tropical Pacific and Dipole Events in the Indian Ocean

• Published in: Acta meteorologica Sinica Vol. 20; no. 2; pp. 223 - 231
• Main Author: 巢纪平 巢清尘 刘琳
• Format: Journal Article
• Language: English
• Published: Beijing Springer Nature B.V 01.04.2006; National Marine Environment Forecast Center, Beijing 100081; The First Institute of Oceanography, SOA, Qingdao 266061%National Climate Center, Beijing 100081%The First Institute of Oceanography, SOA, Qingdao 266061; Ocean University of Qingdao, Qingdao 266003
• Subjects: Ocean temperature; Oceanography; 印度洋; 太平洋; 海水温度; Indian Ocean; Dipole; depth map of maximum sea-temperature anomaly; ENSO; coupled evolving of Walker circulations
• ISSN: 0894-0525; 2191-4788

A depth map （close to that of the thermocline as defined by 20 ℃） of climatically maximum seatemperature anomaly was created at the subsurface of the tropical Pacific and Indian Ocean, based on which the evolving sea-temperature anomaly at this depth map from 1960 to 2000 was statistically analyzed. It is noted that the evolving sea temperature anomaly at this depth map can be better analyzed than the evolving sea surface one. For example, during the ENSO event in the tropical Pacific, the seatemperature anomaly signals travel counter-clockwise within the range of 10°S-10°N, and while moving, the signals change in intensity or even type. If Dipole is used in the tropical Indian Ocean for analyzing the depth map of maximum sea-temperature anomaly, the sea-temperature anomalies of the eastern and western Indian Oceans would be negatively correlated in statistical sense （Dipole in real physical sense）, which is unlike the sea surface temperature anomaly based analysis which demonstrates that the inter-annual positive and negative changes only occur on the gradients of the western and eastern temperature anomalies. Further analysis shows that the development of ENSO and Dipole has a time lag features statistically, with the sea-temperature anomaly in the eastern equatorial Pacific changing earlier （by three months or so）. And the linkage between these two changes is a pair of coupled evolving Walker circulations that move reversely in the equatorial Pacific and Indian Oceans.