The Relationship Between The East Asian Up-tropopheric Jet Stream In Summer And Climatic Characters Of Synoptic-scale Disturbance

Using the NCEP/NCAR daily data (1979-2003), the relationship between the East Asian up-tropospheric jet stream in summer and climatic characters of synoptic-scale disturbance is analyzed. We examined the relationship between the jet stream and activity of synoptic-scale disturbance Q, which depicts intensity of synoptic-scale disturbance in a period of time, and the relationship between the jet stream and transient eddy heat flux. The results show that in the climatological sense, activity of synoptic-scale disturbance is much stronger in June and August, which is corresponding with the variation of jet stream. Stronger activity of synoptic-scale disturbance is associated with stronger jet stream, and vice versa. The transient eddy heat flux show similar features of activity of synoptic-scale disturbance. On the interannual time scale, there exists significant positive correlation between the transient heat flux and the strength of jet stream in summer (JJA mean), June, July, August, respectively. Composite analysis shows that corresponding to southward displacement of transient eddy heat flux, the strength of jet stream is stronger and vice versa. All results show that climatologically and on the interannual time scale, the East Asian up-tropopheric jet stream in summer and climatic characters of synoptic-scale disturbance are closely connected.