45
Study on the Estimation of Tidal Front at Coastal Sea Area
based on the NOAA Image Analysis
Yukio AKAMATSU, Naoki SHIRAI (Kokusai Kogyo Co., Ltd.)
Tadashi ASAI, Kazuo MURAKAMI
(Port and Harbour Research Institute, the Ministry of Transport)
1. Introduction
It is required for the conservation of oceanic environment and safe navigation of vessels to
grasp the distribution of floating garbage for effective garbage collection. Since the floating
garbages are incessantly changing their positions under the influence of oceanic and
meteorological conditions, it is necessary to develop the method to extract the area of the
floating garbage distribution at real time. The floating garbage has a nature to concentrate along
the tidal front, so it shows the possibility to estimate the area of floating garbage distribution by
identifying the location of the tidal front.
From the above point of view, the authors developed the tidal front estimation model based
on the NOAA image analysis and applied this model to Osaka Bay, Japan. This study has been
done for the purpose to find out the analysis method of NOAA image suitable for identifying
the location of tidal front.
2. Tidal front estimation model based on automatic processing
The goal of this study is to estimate the location
of tidal front through the image processing,
eventually automatize the estimation by adding
the information of time serial changes, and
construct the system which can be put to
practical use. Figure 1 shows the research plan of
the model development.
In this study,as one of the methods to estimate
the location of tidal front by automatic processing,
we discussed the method to extract the tidal front
through the satellite image processing. Fig. 1: Research plan of the model development
3. Study area and Data used for analysis
We decided the whole area of Osaka Bay as the
study area for analysis. Figure 2 shows the scope of
study area.
The data used for the analysis are the visible,near
infrared and atmospheric correction added sea
surface temperature data (MCSST) of artificial
satellite NOAA data from 1991 to 1992.These
pixel size is about 1.5km.We established the
following selection guideline to discuss the
possibility of identifying the location of tidal front.
Fig. 2: Study area for analysis
Estimation of tidal front
location by image processing
Consideration on time serial change
Automatization
Practical system