Recent years have highlighted that the necessity of ocean data in time and space for the predictions of environmental changes on Earth. As one method of acquiring data, we propose a virtual mooring system using an underwater glider. Using our developed and re-modified prototype vehicle "BOOMERANG", oceanographic observations were made in the west sea-area of Japan's Kami-Goto islands in July, 2015 and in the East China Sea in July, 2016. Details of the observations are presented herein.
In recent years, predictions of environmental changes on Earth and studies of ecodevelopment have become increasingly important. Such predictions necessitate the continuous collection of ocean data in time and space. However, construction of a conventional mooring system requires many labor hours and great expense. Profiling floats such as Argo floats (Roemmich et al., 2009) cannot remain at a specific point where continuous and long-term observations are needed because they float in the current. To solve these problems and to collect the necessary data, we propose a virtual mooring system using an underwater glider and a test-bed vehicle constructed at the Research Institute for Applied Mechanics (RIAM), Kyushu University (Nakamura et al., 2009). Results of a field experiment conducted in March 2010 were satisfactory. Therefore, construction of a prototype vehicle "BOOMERANG" for practical use was begun in April 2010. To improve reliability and to enable prolonged use, the performance of various pieces of loading apparatus of the vehicle was improved (Koterayama et al., 2012). Although the prototype vehicle was completed after in a fashion in 2013, improvements were made after reflecting results of field experiments, and the first formal oceanographic observations were conducted in 2015.
Details of oceanographic observations conducted at the west sea area of the Kami-Goto islands in Nagasaki Prefecture in July, 2015 and those conducted in the East China Sea in July, 2016 are presented in this paper.