1:45 PM - 3:15 PM
[O08-P107] Research the mysterious fire phenomenon called Shiranui 6 ~New perspectives from simulation to contemporary observation~
Keywords:mirage, refraction, observation, simulation, reproduction, optics
The Shiranui phenomenon is a mysterious fire phenomenon observed in the Shiranui Sea facing Kumamoto Prefecture. We have studied Shiranui for six years from three perspectives: observation, simulation, and reproduction. This year, we took on the challenge of understanding the actual situation of Shiranui and conducting experiments to reproduce it, based on the three questions listed below.
Question 1: "Current situation - Can we see Shiranui now?" The results of 23 overnight field observations over six years revealed that Shiranui could not be observed even once and that "Shiranui has not been seen in recent years". However, we were able to confirm a mysterious phenomenon in which the number of visible light sources changed over time from 0 to 1 to 2.
Question 2: "Principle - What is the principle of the mysterious phenomenon we observed?" The simulation scientifically explains that the mysterious phenomenon observed at the time of Hassaku is an inferior mirage at night caused by a large tidal change in the Shiranui Sea. In addition, from our interviews, we learned that there are no fishing fires in the Shiranui Sea because of the modern fishing ban, and that if there were them in the present day, Shiranui may occur and be observable at the observation site.
Question 3: "Reproduction - Can we reproduce Shiranui? ~We attempted to reproduce it by using heaters and fans. We were able to reproduce the lateral mirage by adjusting the position of the camera and the shiranui phenomenon, in which the light from the source expands and contracts horizontally, by blowing a slight breeze in the direction of the line of sight. This is the world's first clear record of this phenomenon.
As a summary of the research, we found that the conditions for occurrence and observation (1) temperature difference between the sea surface and air temperature, (2) cold rivers and vast mudflats, (3) light wind in the direction of the line of sight, and (4) height of the observation point are related, and that although it has been difficult to observe Shiranui in recent years, it may be possible to generate and observe them by using fishing fires. This year, we plan to send a fishing boat to observe Shiranui at night in Hassaku.
Question 1: "Current situation - Can we see Shiranui now?" The results of 23 overnight field observations over six years revealed that Shiranui could not be observed even once and that "Shiranui has not been seen in recent years". However, we were able to confirm a mysterious phenomenon in which the number of visible light sources changed over time from 0 to 1 to 2.
Question 2: "Principle - What is the principle of the mysterious phenomenon we observed?" The simulation scientifically explains that the mysterious phenomenon observed at the time of Hassaku is an inferior mirage at night caused by a large tidal change in the Shiranui Sea. In addition, from our interviews, we learned that there are no fishing fires in the Shiranui Sea because of the modern fishing ban, and that if there were them in the present day, Shiranui may occur and be observable at the observation site.
Question 3: "Reproduction - Can we reproduce Shiranui? ~We attempted to reproduce it by using heaters and fans. We were able to reproduce the lateral mirage by adjusting the position of the camera and the shiranui phenomenon, in which the light from the source expands and contracts horizontally, by blowing a slight breeze in the direction of the line of sight. This is the world's first clear record of this phenomenon.
As a summary of the research, we found that the conditions for occurrence and observation (1) temperature difference between the sea surface and air temperature, (2) cold rivers and vast mudflats, (3) light wind in the direction of the line of sight, and (4) height of the observation point are related, and that although it has been difficult to observe Shiranui in recent years, it may be possible to generate and observe them by using fishing fires. This year, we plan to send a fishing boat to observe Shiranui at night in Hassaku.