资源环境科技发展态势分析平台

The properties of initial leaders (ILs) of 1,056 flashes in two thunderstorms in Guangzhou, China, are analyzed. The median values of IL properties are 11.1 ms for duration, 2.2 km for vertical distance, 2.7 km for 3-D distance, 1.9 x 10(5) m/s for vertical displacement speed, 2.4 x 10(5) m/s for 3-D displacement speed, 28 degrees for angle between the IL's displacement direction and the vertical direction, 1.1 per ms for pulse rate, 179 m for vertical step length, and 224 m for 3-D step length. All the IL properties follow lognormal distributions. Strong monotonic relationships of IL duration with speed and pulse rate and pulse rate with speed and step length are revealed. With increasing initiation altitude, IL duration and step length tend to increase, and IL speed and pulse rate tend to decrease. The ILs initiated at approximately the -20 degrees C isotherm are more vertically orientated on average than those initiated at lower or higher levels. The ILs initiated in the strong kinematic areas generally had a greater speed and pulse rate but smaller duration, distance, and step length relative to those initiated in the weak kinematic areas. The possible impacts of the charge distribution patterns and density on the IL properties in different types of thunderstorms or thunderstorm areas are discussed.