1:45 PM - 3:15 PM
[O08-P106] What? The island is floating!?
~Conditions for the occurrence and observation of floating island and the scientific principles~
Keywords:lower mirage, refraction, temperature difference, reproduction device, Observation point height
[Background and Purpose]The following three objectives were set for this study. 1 To confirm the occurrence and observational conditions of floating islands by our observation, 2 To confirm the conditions of floating islands by reproducing experiments, 3 To visualize the light path of floating islands observed in the field by simulation and explain how floating islands can be seen scientifically.
[A. Field Observation]Observations were made from Eino to Oshima in Shiranui Town, Uki City, at the coast and a viewing site. We compared the following four factors:1 the difference between summer and winter, 2 the difference between morning and afternoon, 3 the difference between the coast and the viewing site, and 4 the difference in distance. The observations revealed that the conditions for the occurrence and observation of floating islands are 1 early morning in winter (December and January), 2 close to the sea surface (on the coast at high tide), and about 10 km from the target.
[B. Floating-island generation and observation conditions]A floating island reproduction device was created using a silicon rubber heater and a camera temperature controller to reproduce the floating island phenomenon indoors. The experiment was conducted by changing 1 the temperature of the heater and 2 the height of the observation point. It was found that 1 the higher the heater temperature, the more the island appeared to float, and 2 the lower the height of the observation point, the more the island appeared to float. However, even if the heater temperature was high, if the height of the observation point was high, the object did not appear to float very much. This indicates that the height of the observation point has a significant effect, and we were able to confirm this in actual observations.
[C Principle of floating island generation]The vertical distribution of air temperature over the heater as a function of heater temperature was measured up to a height of 1 meter. As the heater temperature increased, the thickness of the air layer became thicker. The light is refracted due to the density difference caused by the temperature change, resulting in a mirage.
[D Explanation by simulation] To reproduce the situation observed, a temperature profile was created and an original simulation was used to calculate the light path. The results showed that the appearance differs depending on the height of the viewer and that the lower the height of the observation point, the larger the vanishing and inverted areas become, and the more the islands appear to float.
[E Verification The range in which light is refracted]
The floating condition was examined by changing the position of the heater and the height of the observation point with the device. From the experiment, we found that 1 the temperature difference near the object is important for observing a lower mirage, and 2 the location where light is refracted moves closer to the object as the height of the observation point increases.
[Summary]We confirmed the correctness of the following three conditions for the occurrence and observation of floating islands, which were identified through field observations, indoor replication experiments, and simulations. 1 There is a temperature difference between air and seawater temperatures...early morning in December or January, 2 The height of the observation point is low...on the coast at high tide, and 3 There is an appropriate distance...about 10km away.
[A. Field Observation]Observations were made from Eino to Oshima in Shiranui Town, Uki City, at the coast and a viewing site. We compared the following four factors:1 the difference between summer and winter, 2 the difference between morning and afternoon, 3 the difference between the coast and the viewing site, and 4 the difference in distance. The observations revealed that the conditions for the occurrence and observation of floating islands are 1 early morning in winter (December and January), 2 close to the sea surface (on the coast at high tide), and about 10 km from the target.
[B. Floating-island generation and observation conditions]A floating island reproduction device was created using a silicon rubber heater and a camera temperature controller to reproduce the floating island phenomenon indoors. The experiment was conducted by changing 1 the temperature of the heater and 2 the height of the observation point. It was found that 1 the higher the heater temperature, the more the island appeared to float, and 2 the lower the height of the observation point, the more the island appeared to float. However, even if the heater temperature was high, if the height of the observation point was high, the object did not appear to float very much. This indicates that the height of the observation point has a significant effect, and we were able to confirm this in actual observations.
[C Principle of floating island generation]The vertical distribution of air temperature over the heater as a function of heater temperature was measured up to a height of 1 meter. As the heater temperature increased, the thickness of the air layer became thicker. The light is refracted due to the density difference caused by the temperature change, resulting in a mirage.
[D Explanation by simulation] To reproduce the situation observed, a temperature profile was created and an original simulation was used to calculate the light path. The results showed that the appearance differs depending on the height of the viewer and that the lower the height of the observation point, the larger the vanishing and inverted areas become, and the more the islands appear to float.
[E Verification The range in which light is refracted]
The floating condition was examined by changing the position of the heater and the height of the observation point with the device. From the experiment, we found that 1 the temperature difference near the object is important for observing a lower mirage, and 2 the location where light is refracted moves closer to the object as the height of the observation point increases.
[Summary]We confirmed the correctness of the following three conditions for the occurrence and observation of floating islands, which were identified through field observations, indoor replication experiments, and simulations. 1 There is a temperature difference between air and seawater temperatures...early morning in December or January, 2 The height of the observation point is low...on the coast at high tide, and 3 There is an appropriate distance...about 10km away.