Abstract: By using the summer torrential rain days data in Ningxia, the Yinchuan sounding data and the NCEP/NCAR reanalyzed data, the evolutional characteristics and the cause of torrential rain days in Ningxia were analyzed under the background of climate warming. The results show that both annual torrential rain days and annual mean temperature displayed consistent increasing trends. Further analysis results indicate that atmospheric potential instability has grown in the daytime in both July and August and in the nighttime in July, but weakened in the nighttime in August after the climate warming of Ningxia. Therefore, the climate warming not only caused more distinctive diurnal variation of the vertical distribution of atmospheric temperatures in Yinchuan, but also resulted in the increase of torrential rain days and in more obvious diurnal variation of the torrential rain in Ningxia.

Key words: climate change, torrential rain days, atmospheric circulation, formation mechanism, Ningxia