Invited Lecture（Toshio Koike）
In Asia, we have a lot of water-related issues; flood and drought problem, landslidesproblem, the water scarcity from rapid increase of the population, water pollution andthe ecosystem degradation due to the human activity. Under these vulnerable conditions,the climate change impact on the water cycle is one of the most serious problems in thisregion.
By using the satellite, we can identify the cloud system in Eastern Asia which caused
this heavy rainfall. Next, we can also identify the flow of the water vapor by the mixingof various systems; cyclonic system, anti-cyclonic system and the water vapor seam orsource from the Arabian Sea and Bay of Bengal. The convergence of the water vapor
flow leads to Japan. To reduce the flood damage of a river in Japan, we need to consider
and improve our understanding of this system including our prediction ability of thissystem. It can be used not only in Japan, but also in all of the Asian countries. Theinteresting question is how to generate this system?
The system in Asia can be explained as follow. In spring from March to April, a verystrong sunshine and a very thin air mass are over the Tibetan Plateau and very effective
atmospheric heating happens. In the Indian Ocean, a cold air mass exists and thedifference of the air temperature is called this Monsoon Circulation. From the Arabian
Sea and the Bay of Bengal, a lot of water vapor is released and there is the orthographic
effect of the Himalayan Mountains. The very big cloud system is generated and hugeenergy is also released. Then, this Monsoon system is enforced and maintained. Thissystem provides a lot of rain in this region and for some reason, some weakness of theheating over the Asian continent causes the weak Monsoon and causes drought. So thisentire operation is also very important. This is a natural variation of the water cycle inAsia.
We predicted this phenomenon of a change in the water cycle associated with global
warming at the end of the 1980’s by using a super computer. In the middle of the 1990’s
our super computing power is much improved and annum variation of the rainfall canbe predicted. In case of South India, the average of the rainfall increases. This is a very
good signal for India but at the same time, the variation of the annual variation also
becomes bigger. It means that India will face heavy flood and drought more often. Thiskind of bigger annual variation makes water resource management more difficult.
Nowadays we have an earth simulator. This is one of the highest performances of thecomputing system developed by Japan. It can simulate the past 100 years from 1900 andpredict up to 2100. However, we need a cooperation framework and people who work

together. I have been developing the down scale system from the global model output tothe local water cycle information by combining satellite observation or with a numerical
weather prediction model. Next, the prediction ability of the heavy rainfall is improved.
That output is passed to the river runoff model and optimization scheme can reduce theflood in downstream. By using the improved rainfall prediction, we developed the DamOperation Optimization System for reduction of the flood peak and to keep the water
for water use. We applied this system to the Tone River basin in cooperation with theMinistry of Land Infrastructure and Transport. By using this system, we can predict theheavy rainfall. Then, before the flood event, we release the water and the dam storage
decreases due to the flood. Finally, the downstream flood peak can be reduced very
effectively.
In 1998, I proposed the Coordinated Enhanced Observation period known as CEO, theframework of the world climate research program this is sponsored by UNESCO andthe World Meteorological Organization a United Nations organization and ICSUInternational Council of Sciences.
From July 2001 to December 2004, I proposed the integration of the data set of theglobal water cycle and we got three unique capabilities through this project. We
organized 35 science communities who are now implementing the field observation in
the world. They can cover almost all varieties of the climate of this earth. In cooperation
with space agencies, the Japan Aerospace and Exploration Agency, NASA, NOR, ISA,
and the other space agencies are all providing satellites for that.
I’m very happy that political leaders recognize the importance of this kind of functionalso, based on the discussion at (1) the World Summit for Sustainable Development in
Johannesburg, September 2002, (2) the G-8 summit in France in June 2003, (3) Tokyo,February 2005. The 10 years implementation plan and the Global Earth Observation
System (GEOS) were established in Tokyo. The 91 countries, 45 national organizations
gathered together in this framework. The vision of GEOS is to realize a future wherein
decisions and actions for the benefit of human kind are informed by coordinated andcomprehensive and sustained Earth observations and information. We established theinternational framework. Then, to address the water issue in Asia to promote integrated
water resources management by making usable information from GEOS, I proposed at
the Asian Water Cycle Initiative to my colleagues in Asia.