An Experiment on the Air Flow Structure in a Meso- βHail System Using a Single New Generation Weather Radar

Based on data from the China new-generation weather radar (CINRAD), a comprehensive study of a meso-βhail system occurring in central Gansu on 30 May 2005 is performed as regards the evolution of reflectivity intensity and radial velocity as well as variations in the retrieved horizontal wind structure and height of echo zone base. The following results are that: 1) the hail system has a lifecycle of 3.5 h,experiencing the genesis of new cells and decay of old ones, together with the merging of multiple cells, and each cell has its own flow field and the connection of such elds favors the merging and intensi cation of cells, and cells 4 and 8 are responsible for hailfall; 2) the hail system is produced in a large-scale background consisting of a NWW environmental wind, low-level warm, and high-level cold advection, with the hail system depending on joint e ects of northwest, northeast, easterly, and southeast winds for its evolution, and the flow field is marked by cyclonic convergence at low, jets at middle, and anticyclonic divergence at higher levels; and 3) the horizontal resolution is 2 km during the retrieval experiment with horizontal winds, which is unable for us to investigate the flow structure of a cell inside the system but successful analysis is made of formation causes, dynamic structure, and behaviors of the hail system.