Modulation of the Intraseasonal Variability of Pacific-Japan Pattern by ENSO

作者：Ying LI,Fei LIU,Pang-Chi HSU

摘要：This study investigates how the El Nino-Southern Oscillation(ENSO)modulates the intraseasonal variability(ISV)of Pacific-Japan(PJ)teleconnection pattern.The PJ index during boreal summer is constructed from the empirical orthogonal function(EOF)of the 850-hPa zonal wind(U850)anomalies.Distinct periods of the PJ index are found during El Nino and La Nina summers.Although ISV of the PJ pattern is significant during 10-25 days for both types of summers,it peaks on Days 30 and 60 in El Nino and La Nina summers respectively.During El Nino summers,the 30-day ISV of PJ pattern is related to the northwestward propagating intraseasonal oscillation(ISO)over the western North Pacific(WNP),which is originated from the tropical Indian Ocean(IO).During La Nina summers,the 60-day ISV of PJ pattern is related to the northeastward propagating ISO from the tropical IO.The low-frequency ISV modes in both El Nino and La Nina summers are closely related to the boreal summer ISO(BSISO),and the high-frequency ISV modes over WNP are related to the quasi-biweekly oscillation.The underlying mechanisms for these different evolutions are also discussed.

发文机构：Earth System Modeling and Climate Dynamics Research Center

关键词：Pacific–Japan(PJ)patternElNino–SouthernOscillation(ENSO)intraseasonalvariability(ISV)intraseasonaloscillation(ISO)intraseasonaltimescalelow-frequencyISVmodeborealsummerISO

分类号： P73[天文地球—海洋科学]