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Research on artificial rainfall and snowfall : Planned weather modification

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@Recently, 100 or more operational artificial rainmaking projects have been conducted every year in about 40 countries all over the world, including the Asian nations of China, Thailand, Indonesia, South Korea and so on. Aggravation of water shortages continues to be predicted due to population growth and changes in precipitation distribution resulting from climate change. Even in Japan, water shortages arise once every few years in densely populated areas.

@From 1994 to 2003, MRI and the Tone River Dams Integrated Control Office conducted joint research on the feasibility of precipitation augmentation as part of a policy to help ensure a stable supply of water in the Kanto district.

@Since FY 2006, MRI had conducted a five-year research project called Japanese Cloud Seeding Experiments for Precipitation Augmentation in cooperation with several other research organizations under the program of Special Coordination Funds for Promoting Science and Technology funded by Japan's Ministry of Education, Culture, Sports, Science and Technology. The program had two main goals. The first was to promote the development of sophisticated weather modification technology for orographic snow clouds based on the improvement of monitoring techniques for quantitative evaluation of seedable clouds and methods for physical/statistical evaluation of seeding effects. The second was to support investigation of the feasibility of enhancing rainfall amounts through hygroscopic seeding (using hygroscopic flares and salt micro-powder) during warm seasons based on laboratory/numerical experimental study of giant CCN activation processes, development of monitoring techniques for clouds with high seedability, and field (airborne) and numerical seeding experiments. The effects of cloud seeding on drought mitigation and water resource management are also assessed using a combination of NHM and hydrological model.

@Since October 2011, MRI has been involved in a collaborative research project on weather modification with the Tokyo Metropolitan Government. In order to renew ground-based AgI generators (which are more than 40 years old) around the Ogouchi Dam 50 km west of Tokyo, the Institute is investigating optimal seeding methods (including the ground-based AgI seeding) to help secure water resources. It is also monitoring the frequency with which seedable clouds appear and evaluating the effects of seeding all year around. To these ends, research is performed using experimental, observational and numerical simulation techniques.

@Information on the physics of clouds and precipitation obtained from this research also contributes significantly to the improvement of high-resolution non-hydrostatic models.

The Joint Research Project for a Renewal of ground-Based AgI generator at Ogouchi Dam (conducted by Bureau of Water Work, Tokyo Metropolitan Government and Meteorological Research Institute)

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Observation site at Ogouchi

The Program of Special Coordination Funds for Promoting Science and Technology "the Japanese Cloud Seeding Experiments for Precipitation Augmentation (JCSEPA)" funded by the Ministry of Education, Culture, Sports, Science and Technology, Japan

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Project Concept
Project Concept
Observation sites
Observation sites in winter
Observation sites
Observation sites in summer

The Joint Project of the Orographic Snow Cloud Modification by Seeding (conducted by Tone River Dams Integrated Control Office and Meteorological Research Institute)

@We have had the problems of water shortage every two or three years.

@In the central part of Japan, where large portions of water resources rely on the snow-melt water from mountain areas, little snowfall in winter and subsequent little rainfall in Baiu season (rainy season) cause a serious problem of water shortage.

@To investigate the possibilities for snowpack augmentation by cloud seeding over the catchment of Tone River Dams, which are the main water supplies to Kanto district, MRI and Tone River Dams Integrated Control Office had carried out the orographic snow cloud modification research project from 1994 to 2003.

@During phase I (1994 ~ 1997), we investigated microphysical structures of natural orographic snow clouds and their seedability by using hydrometeor videosonde (HYVIS), rawinsonde, microwave radiometers, Doppler radar and so on.

@During phase II (1997 ~ 2000), we introduced an instrumented aircraft (B200) to do small-scale cloud seeding with dry-ice pellets and in-situ measurements of snow clouds before and after cloud seeding.

@During phase III (2000 ~ 2003), we introduced another aircraft (C404) in order to carry out repeated, but still small-scale cloud seeding experiments.

Project Concept
Project Concept
Observation sites
Observation sites : MINAMI-UONUMA
Observation sites
Observation sites