Since the 2000 s,extratropical extremes have been more frequent,which are closely related to anomalies of planetary-scale and synoptic-scale systems.This study focuses on a key synoptic system,the extratropical cyclon...Since the 2000 s,extratropical extremes have been more frequent,which are closely related to anomalies of planetary-scale and synoptic-scale systems.This study focuses on a key synoptic system,the extratropical cyclonic vortex(ECV)over land,to investigate its relations with extreme precipitation.It was found that ECVs have been more active post-2000,which has induced more extreme precipitation,and such variation is projected to persist along with increasing temperature within 1.5℃of global warming.An enhanced quasi-stationary vortex(QSV)primarily contributes to the ECV,rather than inactive synoptic-scale transient eddies(STEs).Inactive STEs respond to a decline in baroclinicity due to the tendency of the homogeneous temperature gradient.However,such conditions are helpful to widening the westerly jet belt,favoring strong dynamic processes of quasi-resonant amplification and interaction of STEs with the quasi-stationary wave,and the result favors an increasing frequency and persistence of QSVs,contributing to extreme precipitation.展开更多
The dynamics of eastward shifting cyclonic vortices are investigated in terms of a barotropic primitive equation model, and six experiments are performed. Both the interaction of a cyclonic vortex with vorticity lumps...The dynamics of eastward shifting cyclonic vortices are investigated in terms of a barotropic primitive equation model, and six experiments are performed. Both the interaction of a cyclonic vortex with vorticity lumps and the interaction of the vortex with the shearing basic flow may induce the strengthening of the vortex in a short period, however, the vortex intensity still shows a general decreasing tendency over the whole integration time period. The interaction among the shearing basic flow, cyclonic vortex, and multiple vorticity lumps can change the tendency. The merging of the cyclonic vortex with vorticity lumps in the shearing basic flow of positive vorticity is directly responsible for the maintenance and development of the cyclonic vortex.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.41975083)。
文摘Since the 2000 s,extratropical extremes have been more frequent,which are closely related to anomalies of planetary-scale and synoptic-scale systems.This study focuses on a key synoptic system,the extratropical cyclonic vortex(ECV)over land,to investigate its relations with extreme precipitation.It was found that ECVs have been more active post-2000,which has induced more extreme precipitation,and such variation is projected to persist along with increasing temperature within 1.5℃of global warming.An enhanced quasi-stationary vortex(QSV)primarily contributes to the ECV,rather than inactive synoptic-scale transient eddies(STEs).Inactive STEs respond to a decline in baroclinicity due to the tendency of the homogeneous temperature gradient.However,such conditions are helpful to widening the westerly jet belt,favoring strong dynamic processes of quasi-resonant amplification and interaction of STEs with the quasi-stationary wave,and the result favors an increasing frequency and persistence of QSVs,contributing to extreme precipitation.
基金the National Natural Science Foundation under Grant No.49775263the project of the Tibetan Plateau Experiment(TIPEX)of Atmospheric Science and the 973 Project onheavy rain in China.
文摘The dynamics of eastward shifting cyclonic vortices are investigated in terms of a barotropic primitive equation model, and six experiments are performed. Both the interaction of a cyclonic vortex with vorticity lumps and the interaction of the vortex with the shearing basic flow may induce the strengthening of the vortex in a short period, however, the vortex intensity still shows a general decreasing tendency over the whole integration time period. The interaction among the shearing basic flow, cyclonic vortex, and multiple vorticity lumps can change the tendency. The merging of the cyclonic vortex with vorticity lumps in the shearing basic flow of positive vorticity is directly responsible for the maintenance and development of the cyclonic vortex.
