Temporal and spatial characteristics of two types El Niño

• Main Author: 吳柏瑾
• Other Authors: 洪志誠
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/43194329567211964490

碩士 === 臺北市立教育大學 === 自然科學系碩士班 === 99 === The temporal and spatial characteristics of two types of El; Niño (Eastern Pacific El Niño, EP-EL, and central Pacific El Niño, CP-EL) during 1950-2010 is explored by analyzing HadiSST (Hadley Center Sea Ice and Sea Surface Temperature (SST) data set), NCEP/NCAR reanalysis atmospheric data, and SODA(Simply Ocean Data Assimilation) oceanic data. It shows that EP-EL is initiated in approximately April, near two month earlier than CP-EL. Both types of El Niño peak in winter, while the EP-EL has larger amplitude in mature phase and terminates to La Nina rapidly during the decaying phase compared with CP-EL. The noticeable difference of atmospheric circulation anomalies between EP-EL and CP-EL is that the anticyclone in WNP (Western North Pacific) is well established during boreal autumn for EP-EL, when the Gill-type cyclonic circulation in response to the central Pacific warm SST anomaly is still prominence for the CP-EL. The longitude-height section of atmospheric circulation reveals that the Indian Ocean and the Pacific couple tightly during the developing stage for EP-EL, however the air-sea coupling is insignificant for CP-EL. An eastward/westward propagation of oceanic Kelvin/ Rossby wave is clearly identified during the lifecycle of EP-EL, suggesting that the initiation and termination of EP-EL is closely related with the thermocline-SST feedback process. The thermocline-SST feedback process is weak for CP-EL.