YAMASHITA Akifumi

Examination of the grasp technique of the outbreak situation of the rip current in the Ajirohama shore

INUKAI Naoyuki

In this study, I grasped the outbreak situation of the rip current by performing a field work at the Ajirohama shore which was adjacent in Niigata Donggang. And consider the factor that speed and outbreak distance of the rip current depend on, and it is a purpose to grasp speed and an outbreak interval of the rip current quantitatively even if surge or topography condition changes.
I carried out the field work at the Ajirohama shore, Seiromachi, Kitakanbara-gun, Niigata on December 9, 2015. I spray sea surface coloring agent on the local shore to visualize the rip current, observed rip current from the sky in UAV. For the grasp of condition of the sea at the time of the investigation, I used surge data observed at Niigata offing observatory of Ministry of Land, Infrastructure and Transport Port Authority located in west 10km from the Ajirohama shore which was an investigation place.
Using an estimation type NISHI for a guess of the speed of the rip current, I used an estimation type of Uda and Sasaki for the guess of the outbreak interval between the rip current.
I was able to grasp the speed of size and the rip current of the circulation by visualizing a circulation by the field work of this study, and observing it. And made a necessary investigation item at the time of field work clear than a comparison between observation numerical value and guess numerical value. Because I can suppose speed and an outbreak interval of the rip current to occur if I know the surge condition at the shore grasping bottom of the sea incline when I use speed and the estimation type used it in this study of the outbreak interval, it is thought that can make use for accident prevention.

Please use "previous botton" to return the previous page