青藏高原东部夏季纬向风10-30天振荡特征
投稿时间:2019-01-07  修订日期:2019-03-01  点此下载全文
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作者单位E-mail
王珺雨 南京信息工程大学 wangjy200016@163.com 
韩世茹 河北省气候中心 hanshiru615@163.com 
基金项目:国家自然科学基金面上项目(41575081);国家自然科学基金项目(面上项目,重点项目,重大项目)
中文摘要:利用1980-2013年ECMWF提供的ERA-Interim逐日4时次再分析资料,通过Morlet小波分析、滤波及合成分析等方法,探究了青藏高原东部夏季200hPa纬向风低频振荡的主要周期及对应的低频振荡特征。结果表明:青藏高原东部夏季200hPa纬向风存在显著的低频振荡周期,且在低频振荡不同强度年份其传播特征有显著差异。青藏高原东部夏季200hPa纬向风低频振荡的主要周期为10-30天。在低频振荡强年,低频振荡过程持续时间长,振幅大,而在低频振荡弱年则持续时间较短,振幅较小。纬向传播上,低频振荡强年,青藏高原东部低频振荡中心以向东传播为主。经向传播上,高原东部地区受高纬南移而来的低频振荡中心影响,低频振荡中心向南移动。在位相演变过程中,主要表现为低频东风和低频西风中心在高原东部地区交替出现,其移动方向与纬向和经向传播特征相似。
中文关键词:青藏高原,低频振荡,纬向风,10-30天
 
10-30 day low-frequency oscillation characteristics of zonal wind over the east Tibetan Plateau in summer
Abstract:Based on the ERA-Interim reanalysis data of four times a day provided by ECMWF, the 10-30 day low-frequency oscillation characteristics of zonal wind in its strong and weak years over the Tibetan Plateau in summer is analyzed by Morlet wavelet, filtering and synthesis analysis methods. The result shows that: There are significant periods of low frequency oscillation of 200 hPa zonal wind over the Eastern Tibetan Plateau in summer. The intensity and propagation of oscillation show significant differences. The 10-30 day low-frequency oscillation is the dominate period of 200 hPa zonal wind over the Eastern Tibetan Plateau in summer. In the strong (weak) low-frequency oscillation years, the low-frequency oscillation process duration is long (short) and the amplitude is strong (weak). In zonal propagation, its center moves eastward in the strong low-frequency oscillation years. In meridional propagation, the Tibetan Plateau is influenced by low-frequency oscillation centers from high latitude, and it moves southward. In the process of phase evolution, the low frequency westerly and easterly winds alternate over the Tibetan Plateau. its direction of movement is similar to the zonal and meridional propagation.
keywords:The Tibetan Plateau, Low-frequency Oscillation, Zonal wind, 10-30 day
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