GIS and Remote Sensing in Hydrology, Water Resources and Environment (Proceedings of ICGRHWE held at the Three Gorges Dam, China, September 2003). IAHS Publ. 289, 2004,122-131

1 Department of Environmental and Mathematical Sciences, Faculty of Environmental Science and Technology, Okayama University, 1-1, Naka 3-chome, Tsushima, Okayama 700-8530, Japan

2 The Graduate School of Natural Science and Technology, Okayama University, 1-1, Naka 3-chome, Tsushima, Okayama 700-8530, Japan

Abstract An experimental and numerical method to incorporate measurements obtained through a global positioning system (GPS) into analysis of a flow in the water environment is described. In previous studies, experiments were conducted to investigate unsteady flows generated in Kojima Lake using a float equipped with a GPS unit, which we call the GPS-float. A finite element method was applied to equations governing their dynamics to analyse the unsteady flows numerically. The results of the finite element analysis were introduced into computational analysis of the momentum equation of the GPS-float to simulate its motion. Those numerical results are presented, and the similarity and the difference between those numerical results and the experimental results were examined. A result of depth measurement to update data associated with the nodes in a finite element mesh is also introduced. Those techniques are illustrated with examples.

Key words finite element method; global positioning system; Kojima Lake; water environment