An artificial rainfall experiment was conducted using an aircraft to seed liquid carbon dioxide (LCD) under particular weather and topographic conditions near the northern area of Saijo, Ehime, with the climatic type of the Inland Sea of Japan on Dec. 27, 2013. Following the seeding, a convective cloud developed quickly above Saijo between 11:30 and 11:50, and rain fell within a short time. A high cumulus cloud was dissipated by the rain, and the cloud over a mountainous area had rapidly and almost completely disappeared by around 12:30, approximately one hour after seeding. The rain at 5 mm/h was observed for 5−6 minutes at around 11:50 at the Saijo City office area, and 0.5 mm of rain was observed up until 13:00 at the Saijo Fire Station. This rainfall was believed to be artificial, and it was significant in the southern mountainous area of Niihama and could be clearly observed visually throughout the area from the aircraft at around 12:10. The artificial rainfall was expected to be observed at amounts of 0.5 mm and 4.0 mm at Ohjoin and Besshiyama of Niihama Fire Station, respectively, and at 0.5 mm during the period from 11:50−12:00 at AMeDAS Tomisato located south of Shikokuchuo. Rainfalls of 0.5 mm from 14:20−14:30 at AMeDAS Ikeda, 2.0 mm from 13:30−15:00 at AMeDAS Kyojo, and 1.0 mm from 13:00−15:00 in the areas of Miyoshi, Tokushima, and Ohtoyo, Kochi, were thought to be artificial considering the seeding time, seeding position, wind direction, and wind speed. The main line of the rainfall area was Saijo− Besshiyama−Kyojo, and the effect of the artificial rainfall expanded up to 70 km of the lee side. The amount of rain was estimated at roughly 1.3 million tons in the areas of Saijo, Ikeda, Sugeo, and Kurotakigawa. Thus, the artificial rainfall experiment conducted through the seeding of LCD at Saijo was clearly successful.
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