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35 Results Found

  • Article
  • Open Access
14 Citations
3,082 Views
16 Pages

20 June 2021

The interferometric imaging radar altimeter (InIRA) aboard the Chinese Tiangong-2 space laboratory is the first spaceborne imaging radar working at low incidence angles. This study focuses on the retrieval of significant wave heights (SWHs) from InIR...

  • Article
  • Open Access
20 Citations
2,609 Views
27 Pages

Significant Wave Height Retrieval Using XGBoost from Polarimetric Gaofen-3 SAR and Feature Importance Analysis

  • Tianran Song,
  • Qiushuang Yan,
  • Chenqing Fan,
  • Junmin Meng,
  • Yuqi Wu and
  • Jie Zhang

27 December 2022

Empirical algorithms have become the mainstream of significant wave height (SWH) retrieval from synthetic aperture radar (SAR). But the plentiful features from multi-polarizations make the selection of input for the empirical model a problem. Therefo...

  • Article
  • Open Access
11 Citations
2,089 Views
19 Pages

Evaluation of Multi-Incidence Angle Polarimetric Gaofen-3 SAR Wave Mode Data for Significant Wave Height Retrieval

  • Chenqing Fan,
  • Tianran Song,
  • Qiushuang Yan,
  • Junmin Meng,
  • Yuqi Wu and
  • Jie Zhang

31 October 2022

Significant wave height (SWH) is one of the most important descriptors for ocean wave fields. The polynomial regression (PolR) and Gaussian process regression (GPR) models are implemented to explore the effects of polarization and incidence angles on...

  • Article
  • Open Access
4 Citations
2,419 Views
18 Pages

16 April 2022

The interferometric imaging radar altimeter (InIRA) adopts a short baseline along with small incidence angles to acquire interferometric signals from the sea surface with high accuracy, thus the wide-swath sea surface height (SSH) and backscattering...

  • Article
  • Open Access
3 Citations
1,347 Views
21 Pages

22 December 2024

The retrieval of global significant wave height (SWH) data is crucial for maritime navigation, aquaculture safety, and oceanographic research. Leveraging the high temporal resolution and spatial coverage of Cyclone Global Navigation Satellite System...

  • Article
  • Open Access
3 Citations
1,719 Views
22 Pages

18 September 2024

Significant Wave Height (SWH) is a crucial parameter in oceanographic research, essential for understanding various marine and atmospheric processes. Traditional methods for obtaining SWH, such as ship-based and buoy measurements, face limitations li...

  • Article
  • Open Access
18 Citations
6,340 Views
17 Pages

8 December 2014

Nowadays, spaceborne Synthetic Aperture Radar (SAR) has become a powerful tool for providing significant wave height (SWH). Traditionally, validation of SAR derived SWH has been carried out against buoy measurements or model outputs, which only yield...

  • Article
  • Open Access
21 Citations
3,371 Views
19 Pages

30 July 2022

In this study, we investigate sea state estimation from spaceborne GNSS-R. Due to the complex scattering of electromagnetic waves on the rough sea surface, the neural network approach is adopted to develop an algorithm to derive significant wave heig...

  • Article
  • Open Access
36 Citations
6,112 Views
14 Pages

30 September 2015

An ocean surface wave retrieval algorithm, Parameterized First-guess Spectrum Method (PFSM), which was initially developed for C-band Synthetic Aperture Radar (SAR), is modified to extract wave parameters from X-band TerraSAR-X (TS-X) images. Wave pa...

  • Technical Note
  • Open Access
19 Citations
3,970 Views
10 Pages

26 November 2021

This study proposes a significant wave height (SWH) retrieval method based on multi-satellite observations using Global Navigation Satellite System Reflectometry (GNSS-R). The algorithm obtains the signal-to-noise ratio (SNR) through delay-Doppler ma...

  • Article
  • Open Access
6 Citations
2,880 Views
19 Pages

Ocean Wave Inversion Based on a Ku/Ka Dual-Band Airborne Interferometric Imaging Radar Altimeter

  • Chunyong Ma,
  • Lichao Pan,
  • Zhiwei Qiu,
  • Da Liang,
  • Ge Chen,
  • Fangjie Yu,
  • Hanwei Sun,
  • Daozhong Sun and
  • Weifeng Wu

26 July 2022

Ocean wave parameters (OWPs), including wave propagation direction (WPD), significant wave height (SWH), and main wave wavelength (MWW) can be typically retrieved using an interferometric imaging radar altimeter (InIRA). However, the inversion accura...

  • Article
  • Open Access
70 Citations
6,894 Views
13 Pages

25 July 2017

The Chinese Gaofen-3 (GF-3) synthetic aperture radar (SAR) launched by the China Academy of Space Technology (CAST) has operated at C-band since September 2016. To date, we have collected 16/42 images in vertical-vertical (VV)/horizontal-horizontal (...

  • Article
  • Open Access
61 Citations
6,246 Views
17 Pages

29 June 2020

This study validated wind speed (WS) and significant wave height (SWH) retrievals from the Sentinel-3A/3B and Jason-3 altimeters for the period of data beginning 31 October 2019 (to 18 September 2019 for Jason-3) using moored buoy data and satellite...

  • Article
  • Open Access
13 Citations
3,902 Views
19 Pages

5 July 2018

Improved significant wave heights (SWHs) along the east coast of Australia have been estimated using the parameters resolved by a Brown-peaky (BP) retracker through reprocessing of three years of Jason-1 altimetric waveforms. The BP-estimated SWHs ar...

  • Article
  • Open Access
3 Citations
1,660 Views
25 Pages

14 November 2023

The shadow statistical method (SSM) used for extracting the significant wave height (SWH) from X-band marine radar images was further investigated because of its advantage of not requiring an external reference for calibration. Currently, a fixed sha...

  • Feature Paper
  • Article
  • Open Access
16 Citations
6,260 Views
14 Pages

11 July 2017

In this study, we proposed an empirical algorithm for significant wave height (SWH) retrieval from TerraSAR-X/TanDEM (TS-X/TD-X) X-band synthetic aperture radar (SAR) co-polarization (vertical-vertical (VV) and horizontal-horizontal (HH)) images. As...

  • Article
  • Open Access
1 Citations
1,511 Views
25 Pages

22 November 2023

In order to investigate the impact of utilizing multiple pieces of polarization information on the performance of significant wave height (SWH) estimation from Gaofen-3 SAR data, the extreme gradient boosting (XGBoost) models were developed, validate...

  • Article
  • Open Access
7 Citations
3,135 Views
24 Pages

Validation of the Ocean Wave Spectrum from the Remote Sensing Data of the Chinese–French Oceanography Satellite

  • Songlin Li,
  • Huaming Yu,
  • Kejian Wu,
  • Xunqiang Yin,
  • Shuyan Lang and
  • Jiacheng Ye

8 August 2023

Since the launch of CFOSAT on 29 October 2018, more than three years of observational data of ocean wave spectra with a frequency range of 0.02–0.26 Hz and a horizontal resolution of 70–90 km have been obtained. This study compares wave s...

  • Article
  • Open Access
13 Citations
7,398 Views
14 Pages

A Promising Method of Typhoon Wave Retrieval from Gaofen-3 Synthetic Aperture Radar Image in VV-Polarization

  • Qiyan Ji,
  • Weizeng Shao,
  • Yexin Sheng,
  • Xinzhe Yuan,
  • Jian Sun,
  • Wei Zhou and
  • Juncheng Zuo

28 June 2018

The motivation of this work is to explore the possibility of typhoon wave retrieval (the main parameter is significant wave height (SWH)) for C-band Gaofen (GF-3) synthetic aperture radar (SAR) with a wide swath coverage (>400 km). We aim to estab...

  • Article
  • Open Access
12 Citations
3,029 Views
29 Pages

25 May 2023

In this paper, a method for joint sea surface rainfall intensity (RI), wind speed, and wave height retrieval based on spaceborne global navigation satellite system reflectometry (GNSS-R) data is proposed, which especially considers the effects betwee...

  • Article
  • Open Access
26 Citations
4,824 Views
17 Pages

28 August 2018

In this study, an empirical algorithm is proposed to retrieve significant wave height (SWH) from dual-polarization Sentinel-1 (S-1) synthetic aperture radar (SAR) imagery collected under cyclonic conditions. The retrieval scheme is based on the well-...

  • Article
  • Open Access
3 Citations
2,647 Views
17 Pages

5 May 2024

This study introduces a new machine learning-based algorithm for the retrieving significant wave height (SWH) using synthetic aperture radar (SAR) images. This algorithm is based on the azimuthal cut-off wavelength and was developed in quad-polarized...

  • Feature Paper
  • Article
  • Open Access
14 Citations
3,298 Views
35 Pages

4 November 2020

The skills of CODAR SeaSonde coastal high-frequency radars (HFR) located in the West Iberian Peninsula on measuring wave parameters are compared to in situ (buoy) and satellite altimeters (SA) wave observations. Significant wave heights (SWH), wave p...

  • Article
  • Open Access
12 Citations
2,144 Views
19 Pages

7 September 2023

The Chinese-French Oceanography SATellite (CFOSAT) jointly developed by the Chinese National Space Agency (CNSA) and the Centre National d’Etudes Spatiales (CNES) of France carries a wave spectrometer (Surface Waves Investigation and Monitoring...

  • Article
  • Open Access
14 Citations
4,368 Views
26 Pages

Evaluation of Sentinel-6 Altimetry Data over Ocean

  • Maofei Jiang,
  • Ke Xu and
  • Jiaming Wang

21 December 2022

The Sentinel-6 Michael Freilich (S6-MF) satellite was launched on 21st November 2020. Poseidon-4, the main payload onboard S6-MF, is the first synthetic aperture radar (SAR) altimeter operating in an interleaved open burst mode. In this study, the se...

  • Article
  • Open Access
4 Citations
2,693 Views
19 Pages

11 July 2023

The HISEA-1 synthetic aperture radar (SAR) minisatellite has been orbiting for over two years since its launch in 2020, acquiring numerous high-resolution images independent of weather and daylight. A typical and important application is the observat...

  • Article
  • Open Access
56 Citations
5,733 Views
23 Pages

Empirical Algorithm for Significant Wave Height Retrieval from Wave Mode Data Provided by the Chinese Satellite Gaofen-3

  • He Wang,
  • Jing Wang,
  • Jingsong Yang,
  • Lin Ren,
  • Jianhua Zhu,
  • Xinzhe Yuan and
  • Chunhua Xie

26 February 2018

Gaofen-3 (GF-3), the first Chinese civil C-band synthetic aperture radar (SAR), was successfully launched by the China Academy of Space Technology on 10 August 2016. Among its 12 imaging modes, wave mode is designed to monitor the ocean surface waves...

  • Technical Note
  • Open Access
27 Citations
5,722 Views
13 Pages

8 July 2016

A conceptually simple formulation is proposed for a new empirical sea state bias (SSB) model using information retrieved entirely from altimetric data. Nonparametric regression techniques are used, based on penalized smoothing splines adjusted to eac...

  • Article
  • Open Access
8 Citations
2,907 Views
18 Pages

Analysis of Wave Breaking on Gaofen-3 and TerraSAR-X SAR Image and Its Effect on Wave Retrieval

  • Ruozhu Zhong,
  • Weizeng Shao,
  • Chi Zhao,
  • Xingwei Jiang and
  • Juncheng Zuo

18 January 2023

The main purpose of our work is to investigate the performance of wave breaking and its effect on wave retrieval in data acquired from the Chinese Gaofen-3 (GF-3) synthetic aperture radar (SAR) at C-band and the German TerraSAR-X (TS-X) at X-band. Th...

  • Project Report
  • Open Access
3 Citations
4,339 Views
26 Pages

Results of the Dragon 4 Project on New Ocean Remote Sensing Data for Operational Applications

  • Ferran Gibert,
  • Jacqueline Boutin,
  • Wolfgang Dierking,
  • Alba Granados,
  • Yan Li,
  • Eduard Makhoul,
  • Junmin Meng,
  • Alexandre Supply,
  • Ester Vendrell and
  • Jean-Luc Vergely
  • + 5 authors

20 July 2021

This paper provides an overview of the Dragon 4 project dealing with operational monitoring of sea ice and sea surface salinity (SSS) and new product developments for altimetry data. To improve sea ice thickness retrieval, a new method was developed...

  • Article
  • Open Access
1 Citations
2,800 Views
16 Pages

18 March 2022

In this study, sea surface wind speed was retrieved using the Global Precipitation Measurement (GPM) dual-frequency precipitation radar (DPR) Ka-band data. In order to establish the Ka-band model at low incidence angles, the dependence of the DPR Ka-...

  • Article
  • Open Access
12 Citations
4,131 Views
20 Pages

A Real-Time GNSS-R System for Monitoring Sea Surface Wind Speed and Significant Wave Height

  • Jin Xing,
  • Baoguo Yu,
  • Dongkai Yang,
  • Jie Li,
  • Zhejia Shi,
  • Guodong Zhang and
  • Feng Wang

17 May 2022

This paper presents a monitoring system based on Global Navigation Satellite System (GNSS) reflected signals to provide real-time observations of sea conditions. Instead of a computer, the system uses a custom-built hardware platform that incorporate...

  • Article
  • Open Access
26 Citations
4,932 Views
26 Pages

18 January 2023

Spaceborne Global Navigation Satellite System Reflectometry (GNSS-R) is a new remote sensing technology that uses GNSS signals reflected from the Earth’s surface to estimate geophysical parameters. Because of its unique advantages such as high...

  • Article
  • Open Access
13 Citations
3,508 Views
17 Pages

29 May 2019

Waveforms of radar altimeters are often corrupted due to heterogeneous sea surface roughness within footprints, such as slicks. In past studies, subwaveform retrackers such as the adaptive leading edge subwaveform retracker (ALES) which use only a se...

  • Article
  • Open Access
1,313 Views
26 Pages

Retrieval of Wave Parameters from GNSS Buoy Measurements Using Spectrum Analysis: A Case Study in the Huanghai Sea

  • Jin Wang,
  • Xiaohang Chang,
  • Rui Tu,
  • Shiwei Yan,
  • Shengli Wang and
  • Pengfei Zhang

18 August 2025

Global Navigation Satellite System (GNSS) buoys are widely used to retrieve wave parameters such as significant wave heights (SWHs) and dominant wave periods. In addition to the statistical methods employed to estimate wave parameters, spectral-analy...