青藏高原低涡群发性与10～30天大气低频振荡关系的初步研究  

Preliminary Study on Relationship between Clustering Activity of Tibetan Plateau Vortex and 10～30 day Low-Frequency Oscillations

作　　者：张鹏飞[1] 李国平[1] 王旻燕[2] 白爱娟[1] 

机构地区：[1]成都信息工程学院大气科学学院/高原大气与环境四川省重点实验室,四川成都610225 [2]中国气象局国家气象信息中心,北京100081

出　　处：《高原气象》2010年第5期1102-1110,共9页Plateau Meteorology

基　　金：国家自然科学基金项目(40875023;40701112);成都信息工程学院校选项目(CRF201001)共同资助

摘　　要：通过统计1998年和2003年5-9月500 hPa高原低涡出现的时空位置和频数,确定出1998年和2003年的低涡群发期,着重讨论1998年夏季500 hPa相对涡度场、射出长波辐射（OLR）的10-30天低频振荡特征。结果表明：高原低涡的发生具有群发性特点,低涡群发期的出现具有周期性特征。低涡群发期与10-30天大气低频振荡有密切联系,尤其是10-30天振荡对低涡的群发具有重要影响。绝大多数高原低涡出现在10-30天大气低频振荡的正位相（气旋性）位相期和对流扰动的负位相（对流性）位相期,高原低涡群发期几乎都对应相对涡度10-30天振荡的气旋性位相期。10-30天大尺度正涡度的扰动为高原低涡的发生和维持提供了气旋性旋转的动力条件,促使高原低涡在扰动正位相期频繁发生,大气相对涡度的10-30天振荡对高原低涡的群发性具有重要的调制作用。青藏高原地区对流活动10-30天振荡的对流性位相是以低涡的群发为主要特征,高原低涡在对流位相期反复、连续地发生、发展,促使对流扰动活跃发展。The temporal-spatial locations and frequencis of Tibetan Plateau（TP） Vortex occurred from May to September 1998 and 2003 are statistically analyzed,the clustering activity periods of TP Vortex in 1998 and 2003 have been determined,500 hPa relative vorticity and 10～30 day low-frequency oscillation（LFO） of OLR are discussed also.The results show that the occurrence of TP Vortex is of clustering activity feature and periodicity.The nine active periods of TP Vortex are closly associated with 10～30 day and 30～60 day LFOs.The most of TP Vortex developed in the positive phase（cyclone） of 10-30 day LFO and negative phase（convection） of convective disturbance.All nine active periods of TP Vortex are corresponding to the cyclonic phase of 10～30 day oscillations.The 10～30 day positive vorticity turbulence provided the cyclonic vortictiy dynamics condition for development and maintenance of TP Vortex to make for the frequently development of TP vortex in positive phase of turbulence.It is found that the 10～30 day oscillations of relative vorticity of atmosphere are of improtant modulation action for clustering activity of TP Vortex.The convective phase of 10～30 day oscillations of convective activity in TP is to take the clustering activity of TP Vortex as main character.TP Vortex repeatedly and continuously develops in convective phase to make for the active development of convective disturbance.

关 键 词：青藏高原 低涡群发期 10-30天振荡 相对涡度 OLR 

分 类 号：P433[天文地球—大气科学及气象学]