Numerical study on structure of meso-β scale rainstorm system during IOP523 of HUAMEX

One of the scientific goals of HUAMEX (Torrential Rainfall Experiment over Both Sides of the Taiwan Strait and Adjacent Area), a special project in the National "863" Scientific Project, is to reveal meso-β scale structure of heavy rainfall. However, limited by the observational instruments, the resolution of the data attained from the outfield scientific observation network cannot reveal the meso-β scale structure. A 36-h numerical simulation of heavy rainfall case from May 23 to May 24, 1998 during IOP523 of HUAMEX was performed by the mesoscale numerical model of PSU/NCAR MM5, and the meso-p scale structure of con-vective system was examined based on the model output in this note. The results point out that the meso-β scale features of the heavy rainfall are clear considerably at low, middle and upper levels, respectively. There is a strong ageostrophic feature between the geopotential height field and the wind field on the upper level. The vertical cross sections of 54 km coarse grid and 18 km fin