Asymmetry of Salinity Variability in the Tropical Pacific during Interdecadal Pacific Oscillation Phases  

作　　者：Hai ZHI Zihui YANG Rong-Hua ZHANG Pengfei LIN Jifeng QI Yu HUANG Meng DONG 

机构地区：[1]College of Atmospheric Sciences,Nanjing University of Information Science and Technology,Nanjing 210044,China [2]School of Marine Sciences,Nanjing University of Information Science and Technology,Nanjing 210044,China [3]Laoshan Laboratory,Qingdao 266237,China [4]State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG),Institute of Atmospheric Physics(IAP),Chinese Academy of Sciences,Beijing 100029,China [5]Key Laboratory of Ocean Circulation and Waves,Institute of Oceanology,and Center for Ocean Mega-Science,Chinese Academy of Sciences,Qingdao 266071,China

出　　处：《Advances in Atmospheric Sciences》2023年第7期1269-1284,共16页大气科学进展（英文版）

基　　金：supported by the National Natural Science Foundation of China(NSFC;Grant No.42030410);the Laoshan Laboratory(Grant No.LSKJ202202403);the National Key Research and Development Program on Monitoring,Early Warning and Prevention of Major Natural Disaster(Grant Nos.2019YFC1510004,2020YFA0608902);supported by the NSFC(Grant No.41976026);supported by the Startup Foundation for Introducing Talent of NUIST。

摘　　要：It has been recognized that salinity variability in the tropical Pacific is closely related to the Interdecadal Pacific Oscillation(IPO).Here,we use model simulations from 1900 to 2017 to illustrate obvious asymmetries of salinity variability in the tropical Pacific during positive and negative IPO phases.The amplitude of salinity variability in the tropical Pacific during positive IPO phases is larger than that during negative IPO phases,with a more westward shift of a large Sea Surface Salinity(SSS)anomaly along the equator.Salinity budget analyses show that the asymmetry of salinity variability during positive and negative IPO phases is dominated by the difference in the surface forcing associated with the freshwater flux[FWF,precipitation(P)minus evaporation(E)],with a contribution of 40%–50%near the dateline on the equator.Moreover,the relationships between the salinity variability and its budget terms also show differences in their leadlag correlations during positive and negative IPO phases.These differences in salinity variability during different IPO phases produce asymmetric effects on seawater density which can reduce or enhance upper-ocean stratification.Therefore,the salinity effects may modulate the intensity of El Nino-Southern Oscillation(ENSO),resulting in an enhanced(reduced)El Nino but a reduced(enhanced)La Ni?a during positive(negative)IPO phases by 1.6℃psu^(-1)(1.3℃psu^(-1)),respectively.It is suggested that the asymmetry of salinity variability may be related to the recent change in ENSO amplitude associated with the IPO,which can help elucidate ENSO diversity.

关 键 词：salinity variability asymmetry upper-ocean stratification Interdecadal Pacfic Oscillation tropical Pacific 

分 类 号：P731.12[天文地球—海洋科学]