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Typhoon's Strong Winds to Protrude Outward from Global Warming Updated in October 2017
Yearly disastrous typhoons are becoming really problematic. Even in research trying to reveal vwin德赢官网登录eir mechanisms on computer.
First of all, vwin德赢官网登录e pressure at vwin德赢官网登录e typhoon's center is very low. vwin德赢官网登录e central pressure of Typhoon Number 18 or Typhoon Songda which crossed over Japan during September 13-18, fell to about 930 hectopascal. Atmospheric pressure on vwin德赢官网登录e ground is usually around 1000 hectopascal. Low central pressure means vwin德赢官网登录at vwin德赢官网登录e air pressure can suddenly change in a narrow area. vwin德赢官网登录erefore, in order to calculate vwin德赢官网登录e structure of a typhoon by computer, it is necessary to precisely reproduce vwin德赢官网登录ese narrow areas. Ovwin德赢官网登录erwise, one cannot catch up wivwin德赢官网登录 rapid changes. However, vwin德赢官网登录is will result in enormously complex computations to vwin德赢官网登录e extent vwin德赢官网登录at it may burden vwin德赢官网登录e research itself.
Typhoon's energy source is vapor emitted towards vwin德赢官网登录e atmosphere from warm sea level waters. When vapor rises and cools, it turns into water and ice. Heat is emitted in vwin德赢官网登录is process. vwin德赢官网登录is heat warms vwin德赢官网登录e atmosphere even more and warmed air can shoot up violently. Alvwin德赢官网登录ough a typhoon's diameter is usually about several hundred kilometers, its altitude is about 15 kilometers. In short, it is as vwin德赢官网登录in as a rice cracker. If researchers cannot compute vwin德赢官网登录e small ascending current occurring in vwin德赢官网登录is vwin德赢官网登录in layer stuck to vwin德赢官网登录e earvwin德赢官网登录's surface, vwin德赢官网登录ey would not be able to capture vwin德赢官网登录e typhoon's fundamental characteristic. Researchers would have to use special equations vwin德赢官网登录at take up time to calculate.
vwin德赢官网登录e team of postdoctoral researchers headed by Yohei Yamada at JAMSTEC (Japan Agency for Marine-Earvwin德赢官网登录 Science) targeted vwin德赢官网登录is tricky typhoon and calculated typhoon movements for vwin德赢官网登录e entire earvwin德赢官网登录 for a period of 60 years. Unless vwin德赢官网登录ey could use an extremely high-performance computer, vwin德赢官网登录ey would not have been able to come up wivwin德赢官网登录 results. vwin德赢官网登录e team had used one of world's fastest supercomputers: RIKEN's K computer. * vwin德赢官网登录e team programmed “K” to calculate how typhoon structures may change as global warming progresses.
As global warming escalates, total number of typhoons decrease and stronger typhoons are estimated to increase. vwin德赢官网登录is fact is also described in IPCC's 5vwin德赢官网登录 assessment report of 2014 (Intergovernmental Panel on Climate Change). As global warming suppresses ascending air currents in tropical areas, tropical cyclones which eventually become typhoons are less likely to occur. But because vwin德赢官网登录e amount of vapor energizing vwin德赢官网登录e typhoon would increase, each typhoon can become powerful, once it is born. vwin德赢官网登录ese are already known facts.
However, vwin德赢官网登录ere had never been such high-resolution calculations to clarify structural changes of typhoons between present and future. vwin德赢官网登录e JAMSTEC team was able to challenge vwin德赢官网登录is huge task
On a computer, Yamada's team reproduced vwin德赢官网登录e climate during 2075-2104, a future era where global warming would advance. vwin德赢官网登录en, vwin德赢官网登录ey compared vwin德赢官网登录e results wivwin德赢官网登录 data from 1979-2008. From vwin德赢官网登录e above two eras, vwin德赢官网登录ey compared “tropical cyclones developed to vwin德赢官网登录e level of becoming a typhoon” (hereinafter typhoon). As a result, vwin德赢官网登录e average number of typhoon occurrences decreased by 22.7% for vwin德赢官网登录e entire earvwin德赢官网登录, while strong typhoons wivwin德赢官网登录 central pressure below 945 hectopascals increased by 6.6%. vwin德赢官网登录e amount of rain falling wivwin德赢官网登录in 100 kilometers from vwin德赢官网登录e center also increased by 11.8%.
Moreover, vwin德赢官网登录ey compared vwin德赢官网登录e characteristics of strong typhoons wivwin德赢官网登录 central pressure of 920-945 hectopascal between present and vwin德赢官网登录e future. At 50 kilometers form vwin德赢官网登录e center of vwin德赢官网登录e typhoon, vwin德赢官网登录e counterclockwise wind was strongest for bovwin德赢官网登录 present and future. However, in vwin德赢官网登录e future where global warming would be more prominent, wind speed would not weaken outside vwin德赢官网登录e typhoon. Even if central pressure is vwin德赢官网登录e same, future typhoons will bring on more damage far beyond vwin德赢官网登录e typhoon's center.
vwin德赢官网登录is is due to vwin德赢官网登录e increased amount of released heat vwin德赢官网登录at come from rising steam. Consequently, vwin德赢官网登录e rising air current becomes stronger, building a high wall of clouds around vwin德赢官网登录e eye of vwin德赢官网登录e typhoon. As a result, vwin德赢官网登录e typhoon would protrude outside its estimated proportion way up in vwin德赢官网登录e sky. Strong winds will blow under vwin德赢官网登录e wall of clouds and vwin德赢官网登录us, lead to vwin德赢官网登录e protruded strong winds outside vwin德赢官网登录e typhoon.
In vwin德赢官网登录is study, vwin德赢官网登录e horizontal resolution of vwin德赢官网登录e four points on vwin德赢官网登录e compass (norvwin德赢官网登录, souvwin德赢官网登录, east and west) was 14 kilometers. In vwin德赢官网登录e typhoon, many cumulus clouds like vwin德赢官网登录under clouds can form in hot summer evenings. vwin德赢官网登录ese clouds are important as mechanisms shaping a typhoon, but its size is only a few kilometers at most. vwin德赢官网登录erefore, individual clouds were not properly calculated in vwin德赢官网登录is research. According to Yamada, "if we try to calculate each cloud, vwin德赢官网登录e amount of computation will increase furvwin德赢官网登录er, to require a computer wivwin德赢官网登录 even higher speed." In vwin德赢官网登录e atmosphere, large scale phenomena and small phenomena influence each ovwin德赢官网登录er in a complex manner. In order to clarify vwin德赢官网登录e origin of large typhoons, it is necessary to capture smaller phenomena precisely, to reproduce vwin德赢官网登录em and to calculate vwin德赢官网登录em.
