Study of the mesoscale -wind field structure of a strong squall line in the Xinjiang Uygur Autonomous Region based on the dual-Doppler radar observations

A process of strong squall line (SSL) occurred near Urumqi in the Xinjiang Uygur Autonomous Region on June 26, 2005 is analysed using the dual-Doppler radar simultaneous observation data from the radars at Urumqi and Wujiaqu and the retrieval technology with a variety of meteorological data (including the automatic meteorological observation station data of one minute interval and sounding data, as well as the NCEP reanalysis data) integrated. The flow field of the process is characterized by the obvious convergence line lying in the lowlevels, convergence in the meddle-level and divergence in a higher level. It would be the main factors for the development of the SSL to generate successively new echos owing to the convergence in the lower levels and merge with the old one at a certain distance right to the old echo (on the southwestern side), and the convergence line between the convection cells will even promote them to combine. The combination among convection cells starts from the middle-level and then extends to the lowlevels. The SSL shows an obvious convergence line after combining with the convection cells in the lowlevels, and the intlow zone, zone of intense echo grads and the zone of feeble echo section are very distinct. In the meantime, every developing phase show a different wind configuration from each other, with the updraft in the multi cell-storm concurrent with the downdraft. Only the strong convection cell lies in the front of the SSL, without stratiform cloud precipitation followed. From the autonomous meteorological observation stations, dual-Doppler radars as well as the retrieval wind field, the occurrence, development and erupting processes of the SSL are well revealed and the spatial structures of the echos and their corresponding wind fields are brought to light as well.