Low-Frequency Oscillations of the East Asia-Pacific Teleconnection Pattern and Their Impacts on Persistent Heavy Precipitation in the Yangtze-Huai River Valley  

作　　者：李蕾 翟盘茂 陈阳 倪允琪 

机构地区：[1]Chinese Academy of Meteorological Sciences,Beijing 100081

出　　处：《Journal of Meteorological Research》2016年第4期459-471,共13页气象学报（英文版）

基　　金：Supported by the National(Key)Basic Research and Development(973)Program of China(2012CB417205);Basic Research Fund of the Chinese Academy of Meteorological Sciences(2015Z001);National Science and Technology Support Program of China(2015BAC03B02)

摘　　要：Based on the daily reanalysis data from NCEP NCAR and daily precipitation data from the China National Meteorological Information Center,an ensemble empirical mode decomposition method is employed to extract the predominant oscillation modes of the East Asia Pacific（EAP） teleconnection pattern.The influences of these low-frequency modes on persistent heavy precipitation in the Yangtze Huai River（YHR）valley are investigated.The results indicate that the EAP pattern and rainfall in YHR valley both exhibit remarkable 10 30- and 30 60-day oscillations.The impacts of the EAP pattern on the YHR persistent heavy precipitation can be found on both the 10 30- and 30 60-day timescales the 10 30-day scale for most cases.Composite analysis indicates that,on the 10 30-day timescale,formation of the EAP pattern in the lower and middle troposphere is determined by convective systems near the tropical western Pacific;whereas in the middle troposphere,the phase transition is jointly contributed by both the dispersion of zonal wave energies at higher latitudes and convective systems over the South China Sea.In the context of the10 30-day EAP pattern,the anomalously abundant moisture is transported by an anomalous subtropical anticyclone system,and strong moisture convergence results from that anomalous anticyclone system and a cyclonic system in the midlatitude East Asia.Such a combination of systems persists for at least three days,contributing to the formation of persistent heavy precipitation in the YHR valley.Based on the daily reanalysis data from NCEP NCAR and daily precipitation data from the China National Meteorological Information Center,an ensemble empirical mode decomposition method is employed to extract the predominant oscillation modes of the East Asia Pacific（EAP） teleconnection pattern.The influences of these low-frequency modes on persistent heavy precipitation in the Yangtze Huai River（YHR）valley are investigated.The results indicate that the EAP pattern and rainfall in YHR valley both exhibit remarkable 10 30- and 30 60-day oscillations.The impacts of the EAP pattern on the YHR persistent heavy precipitation can be found on both the 10 30- and 30 60-day timescales the 10 30-day scale for most cases.Composite analysis indicates that,on the 10 30-day timescale,formation of the EAP pattern in the lower and middle troposphere is determined by convective systems near the tropical western Pacific;whereas in the middle troposphere,the phase transition is jointly contributed by both the dispersion of zonal wave energies at higher latitudes and convective systems over the South China Sea.In the context of the10 30-day EAP pattern,the anomalously abundant moisture is transported by an anomalous subtropical anticyclone system,and strong moisture convergence results from that anomalous anticyclone system and a cyclonic system in the midlatitude East Asia.Such a combination of systems persists for at least three days,contributing to the formation of persistent heavy precipitation in the YHR valley.

关 键 词：East Asia Pacific teleconnection persistent heavy precipitation low-frequency oscillation 

分 类 号：P461.2[天文地球—大气科学及气象学]