摘要
利用小波分析、Butterworth滤波器分析了淮河流域汛期典型旱涝年降水和大气的低频特征,结果表明典型涝年、旱年降水的周期和方差贡献最明显的差异都位于30～60 d周期段。从30～60 d滤波降水峰值位相对应的低频环流来看,高层主要的差异位于东亚,在东西伯利亚地区涝年存在大片负异常区,而旱年则为正异常;涝年平均在东亚自北向南存在"-+-+"的异常配置,而旱年平均的位相近乎相反;低层风场上涝年副热带的低频反气旋比旱年更明显。此外,典型涝年的高低纬地区存在低频信号相向传播的特征,典型旱年则不明显;涝年存在低频信号自太平洋向东亚西传的特征,而旱年的西传仅局限于120 E以东地区。
Using Morlet wavelet analysis and Butterworth filter, low-frequency characteristics of Huaihe River valley＇s typical drought and flood years are analyzed. Results show that there are great differences between drought and flood years. As shown from the contribution of periodicity and variance, the greatest difference is found in the 30-60 period. From low-frequency circulation characteristics corresponding to peak phases of 30-60 d filter rainfall, main difference in high levels lies in East Asia. In flood years, high-to-low latitude configuration is ＂-- ＋ -- ＋＂; in drought years, the phase of wave train is approximately the opposite. In the low-level wind field, a low-frequency anticyclone is more significant in the subtropics. Besides, there are also great differences in propagation characteristics： in flood years, opposite propagation exists in high and low latitudes, which is not clear in drought years; in flood years, westward low-frequency propagation is significant from west Pacific to East Asia, but only limited in areas east of 120 °E in drought years.
出处
《热带气象学报》
CSCD
北大核心
2013年第3期511-516,共6页
Journal of Tropical Meteorology
基金
水利部2009年公益项目(00901024)
安徽省气象局2010年业务能力建设项目(ybyc2010007)共同资助
关键词
典型旱涝
低频振荡
环流特征
淮河流域
typical drought and flood
low-frequency oscillation
circulation characteristics
Huaihe River valley
