江淮持续性暴雨过程前30～60d低频主振荡型特征
The Characteristics of the Principal Oscillation Patterns of the 30-60 d Intra-seasonal Oscillation before the Persistent Heavy Rainfall (PHR) Events over the Vicinity of the Yangtze River Valley
吴建金1
作者信息
- 1. 浙江大学地球科学学院，浙江杭州310027
- 折叠
摘要
利用1951～2010年NCEP／NCAR逐日再分析资料，采用改进后的一阶Butterworth带通滤波、主振荡分析（ POP）和合成分析，研究了近60年4～8月全球大气低频主振荡型特征及其与江淮流域持续性暴雨过程的关系。结果表明，4～8月全球850 hPa高度场存在IN－WPO型（赤道印度洋－西太平洋型）和TA－WE型（热带大西洋－西欧型）2个30～60 d主振荡型。过程前，不同振荡型的时域变化特征明显，反映了全球大气30～60 d低频振荡的显著变化。位相合成分析显示，持续性暴雨过程主要发生在IN－WPO的位相7和TA－WE的位相5后，过程前，当IN－WPO型循环到位相4时，850 hPa低频风场中我国南海、华南等地开始存在显著30～60 d低频风变化，西北太平洋低频气旋和北太平洋低频反气旋的形成和发展，这些低频特征有利于江淮流域持续性暴雨过程形成。
Abstract
The principal oscillation patterns of global atmospheric intra-seasonal oscillation (ISO), and its relation to the persistent heavy rain-fall (PHR)events over the vicinity of the Yangtze River valley (YR) from Apr.to Aug.during 1951-2010 were analyzed statistically based on the NCEP/NCAR reanalysis data and the first–order Butterworth function, the principal oscillation pattern (POP) analysis and composite anal-ysis.The results showed that two dominant POP pairs are found when the POP analysis is applied to the 30-60 d low frequency geopotential heightover850 hPa:IN-WPO and TA-WE.Before the PHR, the variation characteristics of different POPs differ significantly, which reflect the global atmospheric 30-60 d low frequency oscillation in significant change .Composite analyses the global atmospheric 30-60 d low frequen-cy oscillation characteristics based on the change of phases of IN-WPO and TA-WE:most of PHRs happened after the 7 of IN-WPO pattern and phase 5 of TA-WE pattern.Before PHR happens over YR, enhanced 850 hPa low-frequency wind occur over southern part of China, anda low-frequency cyclone is located over WNP over 850 hPa while a low-frequency anticyclone located over northern Pacific in the circulation of the IN-WPO.
关键词
全球大气低频振荡/30~60d/持续性暴雨过程/POP分析/江淮流域Key words
Global atmospheric low frequency oscillation/30-60 d/Persistent heavy rainfall引用本文复制引用
出版年
2016
国家科技期刊平台
NSTL
维普
万方数据