Impact of 10-60-Day Low-Frequency Steering Flows on Straight Northward-Moving Typhoon Tracks over the Western North Pacific  

作　　者：Qiao LIU Tim LI Weican ZHOU 

机构地区：[1]Key Laboratory of Meteorological Disaster, Ministry of Education/Joint International Research Laboratory of Climate and Environmental Change,Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science & Technology [2]International Pacific Research Center and Department of Atmospheric Sciences, School of Ocean and Earth Science and Technology, University of Hawaii

出　　处：《Journal of Meteorological Research》2018年第3期394-409,共16页气象学报（英文版）

基　　金：Supported by the National(Key)Basic Research and Development(973)Program of China(2017YFA0603802 and 2015CB453200);National Natural Science Foundation of China(41630423,41475084,41575043,and 41375095);US National Science Foundation(AGS-1643297);NRL grant(N00173-16-1-G906);Jiangsu Projects(BK20150062 and R2014SCT001);Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)

摘　　要：This study investigates the impact of low-frequency(intraseasonal and interannual) steering flows on straight northward-moving(defined as a meridional displacement two times greater than the zonal displacement) typhoons over the western North Pacific using observational data. The year-to-year change in the northward-moving tracks is affected by the interannual change in the location and intensity of the subtropical high. A strengthened northward steering flow east of 120°E and a weakened easterly steering flow south of the subtropical high favor more frequent straight northward tracks. Examining each of the individual northward-moving typhoons shows that they interact with three types of intraseasonal(10-60-day) background flows during their northward journey. The first type is the monsoon gyre pattern, in which the northward-moving typhoon is embedded in a closed cyclonic monsoon gyre circulation. The second type is the wave train pattern, where a cyclonic(anticyclonic) vorticity circulation is located to the west(east) of the northward-moving typhoon center. The third type is the mid-latitude trough pattern, in which the northward-moving typhoon center is located in the maximum vorticity region of the trough.This study investigates the impact of low-frequency(intraseasonal and interannual) steering flows on straight northward-moving(defined as a meridional displacement two times greater than the zonal displacement) typhoons over the western North Pacific using observational data. The year-to-year change in the northward-moving tracks is affected by the interannual change in the location and intensity of the subtropical high. A strengthened northward steering flow east of 120°E and a weakened easterly steering flow south of the subtropical high favor more frequent straight northward tracks. Examining each of the individual northward-moving typhoons shows that they interact with three types of intraseasonal(10-60-day) background flows during their northward journey. The first type is the monsoon gyre pattern, in which the northward-moving typhoon is embedded in a closed cyclonic monsoon gyre circulation. The second type is the wave train pattern, where a cyclonic(anticyclonic) vorticity circulation is located to the west(east) of the northward-moving typhoon center. The third type is the mid-latitude trough pattern, in which the northward-moving typhoon center is located in the maximum vorticity region of the trough.

关 键 词：intraseasonal steering flow interannual steering flow straight northward-moving typhoon 

分 类 号：P444[天文地球—大气科学及气象学]