Nonlinear internal waves generated and trapped upstream of islands in the Kuroshio

Nonlinear internal waves (NIWs) induce strong surface currents which are observable in synthetic aperture radar (SAR) images. SAR images of the Kuroshio show parabolic features around Japan's Izu Islands implying possible NIWs. Most images were taken during the summer when the Kuroshio approach...

Full description

Saved in:
Bibliographic Details
Published in:Geophysical research letters 2014-07, Vol.41 (14), p.5091-5098
Main Authors: Kodaira, T., Waseda, T., Miyazawa, Y.
Format: Article
Language:English
Subjects:
Geophysics
Internal waves
Islands
Marine
Mathematical models
nonlinear internal waves
Nonlinearity
Ocean currents
Ocean-atmosphere interaction
Summer
Synthetic aperture radar
the Kuroshio
Upstream
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Nonlinear internal waves (NIWs) induce strong surface currents which are observable in synthetic aperture radar (SAR) images. SAR images of the Kuroshio show parabolic features around Japan's Izu Islands implying possible NIWs. Most images were taken during the summer when the Kuroshio approached the islands, and the winds were relatively weak. Nonhydrostatic numerical simulations revealed that around the islands, mode 1 internal waves are not trapped but higher modes, with lower propagation speeds, are trapped. The surface convergence field predicted by the model reproduces prominent, parabolic features observed in the SAR images. Based on this agreement, we suggest that the NIWs are generated around the Izu Islands by the Kuroshio and the parabolic features detected by SAR are surface manifestations of these NIWs. Specific atmospheric and oceanic conditions which are conducive for NIW detection by SAR are defined. Key Points The Kuroshio generates multiple modes of NIWs upstream of the Izu Islands Mode 1 internal waves are not trapped, but the higher modes are trapped Relatively weak winds and stratification in summer promoted SAR to detect NIWs
ISSN:0094-8276
1944-8007
DOI:10.1002/2014GL060113