As a result of analyzing the changes in the way of rain around Japan over the past 40 years with artificial intelligence etc., "abnormal rain" where the amount of rain is extremely heavy or the range of rain is very wide is mainly in western Japan. It has increased and it has become clear that the main cause is global warming associated with human activities.
The frequency of "abnormal rain" is expected to increase nationwide in the future, and experts point out the need to prepare for it regardless of past experience.
NOAA = National Oceanic and Atmospheric Administration, Hiroyuki Murakami's group of Geophysical Fluid Dynamics Research Institute investigates the relationship between recent changes in rain and global warming by simulation with AI = artificial intelligence and supercomputer. I did.
“Abnormal rain” increased significantly in western Japan
First, we let artificial intelligence learn the precipitation data of Japan for 38 years from 1977 to 2015, and the cases where the amount of rain is extremely large or the range is very wide are usually significantly different. Was extracted as.
As a result, the frequency of "abnormal rain" nationwide doubled from 6.1 days in 1977 to 12.3 days in 2015.
It increased remarkably in the Chugoku region, Shikoku, Kyushu, Amami, and western Japan of Okinawa, and increased from 2.7 days to 7.3 days, which was about three times higher.
In particular, when the Baiu front is stagnant, typhoons send in moist air, and there are relatively many patterns of heavy rain.
Global warming due to human activities in the background will increase nationwide in the future
Furthermore, it was found that this increase in "abnormal rain" is due to the global warming that accompanies human activities.
When a supercomputer was used to reproduce in detail natural fluctuations such as atmospheric conditions and changes in seawater temperature such as the "El Nino phenomenon," this increase in "abnormal rain" would occur without global warming associated with human activities. It means that it wasn't.
In the future, "abnormal rain" is expected to increase nationwide, and the frequency is predicted to be about 19 days a year in 2050, which is about three times that of 1977.
It is expected that the number of people approaching Japan will increase while the typhoon is strong, and it is expected that heavy rainfall will increase due to the typhoon and the Baiu front at the end of the Baiu season.
Researcher Murakami said, "There has never been an experiment to separate natural and artificial climate change inside the earth with respect to abnormal rain. In the future, there is a possibility that rain that has never occurred will increase nationwide. We need to be prepared for disasters regardless of past experience. "