Velocity Measurement of Internal Waves in the South China Sea by Multi-Temporal and Multi-Sensor Satellite Images

Title
Velocity Measurement of Internal Waves in the South China Sea by Multi-Temporal and Multi-Sensor Satellite Images
Author(s)
홍단비; 양찬수; Kazuo
KIOST Author(s)
Yang, Chan Su(양찬수)
Publication Year
2013-12-02
Abstract
Oceanic internal waves are generated at the boundary of stratified water layers of different densities associated with salinity and/or temperature. They are often generated by the interaction between the bottom topography and tidal currents. As internal waves propagate the water particles are pushed upward and pulled downward by the stratified boundary, yielding varying surface currents, and these currents move in phase with the internal waves. The varying surface currents produce rough and smooth zones of sea surface, and these differences in surface roughness can be detected by optical imagers and synthetic aperture radars (SARs). In this study, MODIS/Terra and ENVISAT/ASAR were used to obtain sequential images of internal waves in the South China Sea for estimating the propagation properties of internal waves. Most of internal waves in the South China Sea were propagating westward due to strong currents of the Kuroshio. The phase velocities of these internal waves were measured by two methods using 1) multi-temporal and multi-sensor images acquired in a very short time interval, 2) several packets of internal waves associated with semidiurnal tidal period in a single image. The internal wave velocities estimated by the method 1 ranged from 0.84 m/s to 1.91 m/s depending on the water depth, while those by the method 2 were from 0.37 m/s to 0.59 m/s.. As internal waves propagate the water particles are pushed upward and pulled downward by the stratified boundary, yielding varying surface currents, and these currents move in phase with the internal waves. The varying surface currents produce rough and smooth zones of sea surface, and these differences in surface roughness can be detected by optical imagers and synthetic aperture radars (SARs). In this study, MODIS/Terra and ENVISAT/ASAR were used to obtain sequential images of internal waves in the South China Sea for estimating the propagation properties of internal waves. Most of internal waves in the South China Sea were propagating westward due to strong currents of the Kuroshio. The phase velocities of these internal waves were measured by two methods using 1) multi-temporal and multi-sensor images acquired in a very short time interval, 2) several packets of internal waves associated with semidiurnal tidal period in a single image. The internal wave velocities estimated by the method 1 ranged from 0.84 m/s to 1.91 m/s depending on the water depth, while those by the method 2 were from 0.37 m/s to 0.59 m/s.
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/26487
Bibliographic Citation
IEICE Technical Report / ICSANE2013, pp.81 - 85, 2013
Publisher
The
Type
Conference
Language
English
Publisher
The
Related Researcher
Research Interests

Satellite Oceanography,Marine Safety & Security,Remote Sensing,위성해양학,해양 안전 및 보안,원격탐사

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