PRECIPITATION MECHANISMS OF CLOUD SYSTEMS DEVELOPED IN A SEMIARID AREA OF PINGLIANG, CHINA - VIDEOSONDE OBSERVATION

Precipitation mechanisms were investigated in summer rainfall in the s emi-arid region of Pingliang, China as part of the Heihe River Field E xperiment (HEIFE). Evolution of precipitation particles was investigat ed using videosonde images. Radar, surface electric field and balloon ascent rates were also referred for the study. The most noteworthy res ult was finding two completely different rain systems in the area, one in locally developed thunderstorms and the other in rain systems asso ciated with the Baiu front. In the electrically active local thunderst orms, rain is formed through graupel formation. Snowflakes are the pri mary precipitation particles in Baiu frontal cloud systems. The concep t of generation cell involvement in rain formation may not be applicab le in Baiu frontal systems.