Brief description of the rain mitigation operations during Beijing 2008 Olympic opening ceremony

Abstract: Supported by the Beijing Municipal Science & Technology commission key project “Research on the hail suppression, rain mitigation operation during Olympic period”, the technology of the rain mitigation operations during Beijing 2008 Olympic opening and closing ceremony was studied since 2002. The rain mitigation technological scheme and the working flow were made on the base of the study. 18 rain mitigation operation areas were designed according to the weather characteristics and cloud moving direction during August and September in Beijing area, and the prophase experiment results were also analyzed. Weather characteristics, seeding operation and the evaluation of the seeding effect on 8th August were mainly analyzed in the paper. It shows that the intensity of radar echo is weakened , the height of the radar echo is lowered and the area of intense radar echo is decreased dramatically after the rain mitigation operations. Especially, a gap obviously appeared in the radar echo after the seeding operation between 21:45-22:00. In addition, the area of the strong echo was diminished gradually, while the area of the weak echo was increased. The cloud top height and the cloud effective particle radius retrieved from the satellite information over the seeding and control areas show also the effect of the seeding operations.