Japan Geoscience Union Meeting 2023

Presentation information

Poster

O (Public ) » Public

[O-06] Poster presentations by senior high school students

Sun. May 21, 2023 1:45 PM - 3:15 PM Poster (Exhibition Hall 8, Makuhari Messe)

convener:Tatsuhiko Hara(International Institute of Seismology and Earthquake Engineering, Building Research Institute), Katsuyoshi Michibayashi(Department of Earth and Planetary Sciences, Nagoya University), Miwa Kuri(Japan Meteorological Agency), Keiko Konya(Japan Agency for Marine-Earth Science and Technology)

On-site poster schedule (2023/5/21 13:45-15:15)

1:45 PM - 3:15 PM

[O06-P88] Review of the experimental model directed at deep water circulation elucidate

*Ryu Mantani1, *Haruki Yoneda1, Kazumi Igawa1 (1. Zushi Kaisei Senior High School in Kanagawa)

Keywords:Sea


Deep water circulation is the ocean currents that flow over a period of two thousand years from the northern Atlantic, through the Indian Ocean, and to the Pacific Ocean. Due to their scale and lengthy circulation period, deep water circulation is believed to be influenced by global, long-term environmental changes on earth.

Deep water circulation is also believed to be responsible for transporting heat on Earth. In recent years, global warming has been a concern, but by clarifying the deep water circulation, it is believed that we can contribute to maintaining the Earth's environment from a new perspective. In this research, we aim to visualize and analyze water flow in a water tank to study the unexplained part of deep water circulation, the "upwelling", and ultimately understand the mechanism of upwelling.

There is a report from Professor Toshiyuki Hibiya, Professor Emeritus of the University of Tokyo and Visiting Professor of Tokyo University of Marine Science and Technology, there are reports that the tidal currents generated by the moon in deep circulation have an impact.Turbulence is generated in the water by the tidal current hitting seamounts, which conveys heat from the surface to the deep water and causes the deep water to rise due to buoyancy. To verify this hypothesis, experiments have been conducted at our school by focusing on the turbulence generated by tidal currents in the sea, modeling seamounts and oceans using plastic plates and water tanks, analyzing temperature changes, visualizing flows, driving seamounts, and confirming that the temperature difference between upper and lower layers is small. In addition, we have confirmed the existence of vertical upward heat transport turbulence by releasing vitamin B2 into the water tank and visually confirming the generation of turbulence. We have been actively studying deep-sea currents at our school for this purpose.

We took over the research from our seniors in January of this year. The purpose of this study is to clarify the mechanism of "upwelling" and approach the research goal based on the insights of our seniors regarding the improvements of the first experiment and the past research achievements of our school. We aim to confirm whether the "layered structure of the ocean" can be reproduced in the water tank, and then reconsider the experimental method and determine the future research direction.

In the first experiment, we observed the behavior of the water without including underwater mountains. We tried to reproduce the sinking of deep water circulation by cooling the water with ice and visualizing the water mass using the fluorescence of vitamin B2. We also tried to observe the temperature changes using thermometers, but due to the fact that it was our first deep ocean current experiment, the thermometers were not properly placed and ended up being installed in positions closer to the ice-cooled water. Additionally, we took measurements from several locations with the thermometers, but all of them showed a decrease in temperature and there was no noticeable difference in the temperature changes among them. Therefore, we speculated that although we were able to reproduce the sinking of deep water circulation in the first experiment, we may not have been able to reproduce the layer structure of the ocean, or perhaps the improper placement of the thermometers prevented us from obtaining accurate results and discovering the layer structure of the ocean. To address this, we plan to use tape to secure the thermometers and measure the temperature more accurately in the current experiment. We also plan to install three thermometers at equally spaced positions in the upper and lower 5cm points and in the central column.