Interannual variations of North Equatorial Current transport in the Pacific Ocean during two types of El Ni?o  

作　　者：吴国丽 翟方国 胡敦欣 

机构地区：[1]Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China [2]University of Chinese Academy of Sciences, Beijing 100049, China [3]College of Science, China University of Petroleum, Qingdao 266580, China [4]College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao 266100, China

出　　处：《Chinese Journal of Oceanology and Limnology》2016年第3期585-596,共12页中国海洋湖沼学报（英文版）

基　　金：Supported by the National Basic Research Program of China(973 Program)(Nos.2012CB417401,2013CB956202);the Key Project of National Natural Science Foundation of China(No.41330963);the Fundamental Research Funds for the Central Universities(No.201513030)

摘　　要：Interannual variations of Pacific North Equatorial Current （NEC） transport during eastern- Pacific E1 Nifios （EP-EI Nifios） and central-Pacific E1 Nifios （CP-E1 Nifios） are investigated by composite analysis with European Centre for Medium-Range Weather Forecast Ocean Analysis/Reanalysis System 3. During EP-E1 Nifio, NEC transport shows significant positive anomalies from the developing to decay phases, with the largest anomalies around the mature phase. During CP-EI Nifio, however, the NEC transport only shows positive anomalies before the mature phase, with much weaker anomalies than those during EP-El Nifio. The NEC transport variations are strongly associated with variations of the tropical gyre and wind forcing in the tropical North Pacific. During EP-E1 Nifio, strong westerly wind anomalies and positive wind stress curl anomalies in the tropical North Pacific induce local upward Ekman pumping and westward-propagating upwelling Rossby waves in the ocean, lowering the sea surface height and generating a cyclonic gyre anomaly in the western tropical Pacific. During CP-E1 Nifio, however, strength of the wind and associated Ekman pumping velocity are very weak. Negative sea surface height and cyclonic flow anomalies are slightly north of those during EP El Nino.Interannual variations of Pacific North Equatorial Current(NEC) transport during easternPacific El Ni?os(EP-El Ni?os) and central-Pacific El Ni?os(CP-El Ni?os) are investigated by composite analysis with European Centre for Medium-Range Weather Forecast Ocean Analysis/Reanalysis System 3.During EP-El Ni?o,NEC transport shows significant positive anomalies from the developing to decay phases,with the largest anomalies around the mature phase.During CP-El Ni?o,however,the NEC transport only shows positive anomalies before the mature phase,with much weaker anomalies than those during EP-El Ni?o.The NEC transport variations are strongly associated with variations of the tropical gyre and wind forcing in the tropical North Pacific.During EP-El Ni?o,strong westerly wind anomalies and positive wind stress curl anomalies in the tropical North Pacific induce local upward Ekman pumping and westward-propagating upwelling Rossby waves in the ocean,lowering the sea surface height and generating a cyclonic gyre anomaly in the western tropical Pacific.During CP-El Ni?o,however,strength of the wind and associated Ekman pumping velocity are very weak.Negative sea surface height and cyclonic flow anomalies are slightly north of those during EP El Ni?o.

关 键 词：North Equatorial Current TRANSPORT interannual variation El Nino 

分 类 号：P732[天文地球—海洋科学] P732.6