Abstract:A study of the relationship between tropical disturbance and distant rainstorm events in the region of 0°-50°N,90°-150°E during May to September in the period 2006-2011 was performed,while typical cases were selected for statistical analysis and numerical simulation.The results are as follows:(1)Under the background of favorable atmospheric conditions,a tropical disturbancewhose intensity is lower than a tropical depressioncan also cause distant heavy rainfall combining with the effect of mid-latitude systems.The statistics suggest that 21 events can be divided into three categories according to the type of moisture channel on 850 hPa:"S" pattern moisture channel,double moisture channel and northwestward moisture channel.The distant heavy rainfall events with "S" pattern moisture channel occur most frequently and the distant heavy rainfall events occur most frequently in July.The composite analysis of the three types shows that the formation of the remote heavy rainfall is closely related to the atmospheric circulation formed by the mid-latitude systems,tropical disturbance and subtropical high.The mid-latitude systems provide a favorable background of atmospheric circulation and the distant heavy rainfall occurs in the area with high moisture flux,which indicates the importance of moisture transportation.(2)The composite analysis of low-level jet of having or not having distant heavy rainfall shows that the southerly low-level jet located in the east of the tropical disturbance plays an important role in the formation of the distant heavy rainfall and is the key to make a connection between the low-latitude and mid-latitude systems regardless of the tropical disturbance intensity.The diagnosis and numerical study of a case with "S" pattern moisture channel further indicates that the southerly low-level jet is the main channel of transporting moisture to the mid-latitude rainstorm area and its intensity is one of the main factors affecting the distant rainstorm intensity.(3)The diagnosis of a case with "S" pattern moisture channel also indicates that the low-level jet between the tropical disturbance and subtropical high is the main energy channel that transports abundant energy to the distant rainstorm area.So the low-level jet not only contributes to the northward moisture transport but also the energy transport to the distant rainstorm area.(4)Sensitivity experiments show that the tropical disturbance can also induce the propagation of Rossby wave energy towards the northeast,the intensity of which is proportional to the intensity of the tropical disturbance,thus affecting the distant rainfall distribution.Wave trains can not form after removing the tropical disturbance,which is not beneficial to the dispersion of wave energy and the development of the distant rainfall.