Along-Track Interferometry TanDEM-X Satellite Data for Modelling Sea Surface Level Change and Sea Surface Current Velocity

Author(s):  
Maged Marghany ◽  
Nurimah Samnat
Author(s):  
Andreas P. Wijaya

One important parameter in reconstructing and predicting the sea surface elevation from radar images is the surface current. The common method to derive the current is based on 3DFFT with which the (absolute) frequency is derived from a series of images and is fitted to the encounter dispersion relation that consist of the intrinsic exact dispersion relation for linear waves with an additional term that contains the current velocity to be found. The derived dispersion relation will be inaccurate because the images contain many inaccuracies from noise, shadowing, and other radar effects. This paper proposes an alternative method to determine the surface current. Following the method of the Dynamic Averaging and Evolution Scenario (DAES) as presented in [1], the idea is to choose the current velocity that minimizes the difference between an image at a previous time that has been evolved to the time of another image. In order to reduce inaccuracies, an averaging procedure over various images is applied. The method is tested on synthetic data to quantify the accuracy of the results. The robustness of the method will be investigated for several cases of different current parameters (speed and direction) for ensembles of seas with different peak frequency of characteristic sea states.


Author(s):  
Nobuo Kumagae ◽  
Kazuo Kawamura ◽  
Kenji Tatsumi ◽  
Masatada Furuhata ◽  
Masayoshi Tsuchida ◽  
...  

2020 ◽  
Vol 56 (2) ◽  
pp. 249-263 ◽  
Author(s):  
Hee-Young Kim ◽  
Kyung-Ae Park ◽  
Hee-Ae Kim ◽  
Sung-Rae Chung ◽  
Seong-Hoon Cheong

2021 ◽  
Vol 13 (20) ◽  
pp. 4088
Author(s):  
He Yan ◽  
Qianru Hou ◽  
Guodong Jin ◽  
Xing Xu ◽  
Gong Zhang ◽  
...  

Velocity estimation of ocean surface currents is of great significance in the fields of the fishery, shipping, sewage discharge, and military affairs. Over the last decade, along-track interferometric synthetic aperture radar (along-track InSAR) has been demonstrated to be one of the important instruments for large-area and high-resolution ocean surface current velocity estimation. The calculation method of the traditional ocean surface current velocity, as influenced by the large-scale wave orbital velocity and the Bragg wave phase velocity, cannot easily separate the current velocity, characterized by large error and low efficiency. In this paper, a novel velocity estimation method of ocean surface currents is proposed based on Conditional Generative Adversarial Networks (CGANs). The main processing steps are as follows: firstly, the known ocean surface current field diagrams and their corresponding interferometric phase diagrams are constructed as the training dataset; secondly, the estimation model of the ocean surface current field is constructed based on the pix2pix algorithm and trained by the training dataset; finally, the interferometric phase diagrams in the test dataset are input into the trained model. In the simulation experiment, processing results of the proposed method are compared with those of traditional ocean surface current velocity estimation methods, which demonstrate the efficiency and effectiveness of the novel method.


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