Assessment of Clouds Suitable for Summertime Precipitation Augmentation over Shikoku Island

抄録

The appearance frequency and types of clouds suitable for cloud seeding in summer were investigated using operationally available data, such as Multi-functional Transport Satellite and radar-AMeDAS precipitation data. This survey was conducted in Shikoku, Japan, as part of a preparation phase for a weather modification project.
From the viewpoint of drought-prevention measures (i.e., to secure water resources), the appearance frequencies of probably seedable clouds in the warm season (May through September) did not differ greatly between wet or dry months (17-18%). ‘Warm clouds’ suitable for hygroscopic seeding and ‘cold clouds’ suitable for glaciogenic seeding appeared almost equally in the warm season.
During drought periods in mid-summer, the appearance frequency of probably seedable clouds that formed due to local circulation induced by solar radiation tended to be high in late afternoon. Seeding these clouds could be an instantaneously effective way to mitigate drought damage.