Technical Proposal on Possible Control of a Forced Geostrophic Eddy

 

Project Summary:       

 

The objective of this exploratory project is to quantitatively determine the conditions under which the geostrophic eddy in Lake Biwa reverses its direction, from clockwise to counterclockwise or from counterclockwise to clockwise, through field work and numerical modeling. Once successful, such understanding will form a basis for a future follow-on project in which we will investigate how we might control such eddies, or to harvest the power of the eddies as electricity. The desired outcome of the follow-on research effort would be to acquire fundamental information necessary to develop the technology to control a forced geostrophic eddy, which may lead to a patent application.

 

There exist various sizes of eddies in both air and water, but the most energetic ones are geostrophic eddies. Typical eddies containing high energy are typhoons, which can have the energy of 10¹⁸ to 10²⁰ J. Geostrophic eddies are balanced by a pressure gradient and the Coriolis force on Earth. These eddies have horizontal scales of 100-1000 km in air and 1-10 km in water. Most geostrophic eddies are caused by free convection in open areas and it is not easy to control them. However, eddies formed in Lake Biwa, the largest lake in Japan, are called forced geostrophic eddies in a closed area and are excited by solar radiation and wind[1]. Our long-term goal is to find how to control these eddies or to harvest their power. Our short-term goal for this exploratory project is to gain quantitative physical understanding of the dynamics of eddies through field work and numerical modeling.

 

We have studied eddies (“gyres”) of Lake Biwa during the past few decades since 1993 starting with the BITEX93 (BIwako Transport EXperiment) project[2], under normal conditions as well as under extreme weather events (e.g., typhoons)[3]. We have found that they are getting stronger as the global warming proceeds. This tendency is very similar to the development of typhoons in the North Pacific Ocean. If we can control forced eddies, we may apply this for many purposes, such as coast protection, energy extraction, fishery control and even typhoon control in the future. Our proposed study is novel, and we think that a study to control the forced geostrophic eddy in Lake Biwa is critically important for ONR and future generations because of the possible benefits listed above. We will coordinate the study with Dr. Hidekatsu Yamazaki at the Tokyo University of Science and Technology, Dr. Joshua Viers at the University of California, Merced in USA and Dr. Richard Robarts at the World Water and Climate Foundation (WWCF) in Canada.

 

Principle Investigator:       Dr. Michio Kumagai

World Water and Climate Foundation, Japan

5-10 Tsukinowa, Otsu 520-2152, Japan

 

Administrative POC:         Ms. Ayaka Tawada

                                          Manager

World Water and Climate Foundation, Japan

7-1 Yanagasaki, Otsu 525-0022, Japan

 

email: wwcf_japan@nifty.com