-3 s-1; during the tornado maintenance period, the average maximum shear value of mesocyclone reached 51×10-3 s-1. (3) The main characteristics of the dual polarization parameters of the bottom layer of the Gaotang tornado vortex were large horizontal polarization reflectivity factor, small or even negative ZDR and small CC; the temporal and spatial characteristics of TDS were that the bottom CC was less than 0.7, the area of the low CC value area increased significantly with time after the tornado formation, and the bottom CC value was the minimum, increased gradually with height; the area of the low-value area of CC was larger in the lower and top layers, and smaller in the middle layer; the maximum height of TDS gradually increased with time after the tornado formation, and the maximum height of TDS reached 4.8 km when the tornado was strongest, and then decreased gradually; after the tornado dissipating, the TDS characteristics above 1.5° disappeared quickly, and the TDS characteristics at 0.5° elevation continued to maintain for about 11 minutes."/>