Sentinel-1 Noise Suppression Algorithm for High-Wind-Speed Retrieval in Tropical Cyclones

Sentinel-1 cross-polarization (cross-pol) SAR data, known for their unsaturated backscattering characteristics, hold strong potential for high-wind-speed retrieval in tropical cyclones (TCs). However, significant inherent noise in cross-pol data limits retrieval accuracy, especially under moderate-t...

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Main Authors: Dechen Ge, Lihua Wang, Weiwei Sun, Hongmei Wang, Wenjing Jiang, Tian Feng
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Remote Sensing
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Online Access:https://www.mdpi.com/2072-4292/17/11/1827
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author Dechen Ge
Lihua Wang
Weiwei Sun
Hongmei Wang
Wenjing Jiang
Tian Feng
author_facet Dechen Ge
Lihua Wang
Weiwei Sun
Hongmei Wang
Wenjing Jiang
Tian Feng
author_sort Dechen Ge
collection DOAJ
description Sentinel-1 cross-polarization (cross-pol) SAR data, known for their unsaturated backscattering characteristics, hold strong potential for high-wind-speed retrieval in tropical cyclones (TCs). However, significant inherent noise in cross-pol data limits retrieval accuracy, especially under moderate-to-high wind conditions. Existing noise suppression methods remain insufficient due to their limited consideration of spatially varying noise characteristics within different TC structural regions. To address these challenges, this study proposes an enhanced two-dimensional noise field reconstruction framework based on Bayesian estimation, tailored to the structural features of TCs. The method begins by statistically characterizing cross-pol SAR backscatter to differentiate structural regions within TCs. Noise-scaling coefficients are then calculated to suppress scalloping artifacts, followed by the computation of power balance coefficients in sub-swath transition zones to mitigate abrupt inter-strip power variations through signal power equalization. Comparative assessments against the European Space Agency (ESA) noise vectors show that the proposed approach achieves an average signal-to-noise ratio (SNR) improvement of 2.54 dB. Subsequent sea surface wind speed retrievals using the denoised cross-pol data exhibit significant improvements: wind speed bias is reduced from −2.69 m/s to 0.65 m/s, accuracy is improved by 2.04 m/s, and the coefficient of determination (R<sup>2</sup>) increases to 0.88. These findings confirm the effectiveness of the proposed method in enhancing SAR-based wind speed retrieval under complex marine conditions associated with tropical cyclones.
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spelling doaj-art-e84d66015f4d49b8a8f50193ba76a30b2025-08-20T03:11:22ZengMDPI AGRemote Sensing2072-42922025-05-011711182710.3390/rs17111827Sentinel-1 Noise Suppression Algorithm for High-Wind-Speed Retrieval in Tropical CyclonesDechen Ge0Lihua Wang1Weiwei Sun2Hongmei Wang3Wenjing Jiang4Tian Feng5Department of Geography and Spatial Information Techniques, Zhejiang Collaborative Innovation Center for Land and Marine Spatial Utilization and Governance Research, Ningbo University, Ningbo 315211, ChinaDepartment of Geography and Spatial Information Techniques, Zhejiang Collaborative Innovation Center for Land and Marine Spatial Utilization and Governance Research, Ningbo University, Ningbo 315211, ChinaDepartment of Geography and Spatial Information Techniques, Zhejiang Collaborative Innovation Center for Land and Marine Spatial Utilization and Governance Research, Ningbo University, Ningbo 315211, ChinaDepartment of Geography and Spatial Information Techniques, Zhejiang Collaborative Innovation Center for Land and Marine Spatial Utilization and Governance Research, Ningbo University, Ningbo 315211, ChinaDepartment of Geography and Spatial Information Techniques, Zhejiang Collaborative Innovation Center for Land and Marine Spatial Utilization and Governance Research, Ningbo University, Ningbo 315211, ChinaDepartment of Geography and Spatial Information Techniques, Zhejiang Collaborative Innovation Center for Land and Marine Spatial Utilization and Governance Research, Ningbo University, Ningbo 315211, ChinaSentinel-1 cross-polarization (cross-pol) SAR data, known for their unsaturated backscattering characteristics, hold strong potential for high-wind-speed retrieval in tropical cyclones (TCs). However, significant inherent noise in cross-pol data limits retrieval accuracy, especially under moderate-to-high wind conditions. Existing noise suppression methods remain insufficient due to their limited consideration of spatially varying noise characteristics within different TC structural regions. To address these challenges, this study proposes an enhanced two-dimensional noise field reconstruction framework based on Bayesian estimation, tailored to the structural features of TCs. The method begins by statistically characterizing cross-pol SAR backscatter to differentiate structural regions within TCs. Noise-scaling coefficients are then calculated to suppress scalloping artifacts, followed by the computation of power balance coefficients in sub-swath transition zones to mitigate abrupt inter-strip power variations through signal power equalization. Comparative assessments against the European Space Agency (ESA) noise vectors show that the proposed approach achieves an average signal-to-noise ratio (SNR) improvement of 2.54 dB. Subsequent sea surface wind speed retrievals using the denoised cross-pol data exhibit significant improvements: wind speed bias is reduced from −2.69 m/s to 0.65 m/s, accuracy is improved by 2.04 m/s, and the coefficient of determination (R<sup>2</sup>) increases to 0.88. These findings confirm the effectiveness of the proposed method in enhancing SAR-based wind speed retrieval under complex marine conditions associated with tropical cyclones.https://www.mdpi.com/2072-4292/17/11/1827SARSentinel-1cross-polarizationdenoisingwind speedtropical cyclone (TC)
spellingShingle Dechen Ge
Lihua Wang
Weiwei Sun
Hongmei Wang
Wenjing Jiang
Tian Feng
Sentinel-1 Noise Suppression Algorithm for High-Wind-Speed Retrieval in Tropical Cyclones
Remote Sensing
SAR
Sentinel-1
cross-polarization
denoising
wind speed
tropical cyclone (TC)
title Sentinel-1 Noise Suppression Algorithm for High-Wind-Speed Retrieval in Tropical Cyclones
title_full Sentinel-1 Noise Suppression Algorithm for High-Wind-Speed Retrieval in Tropical Cyclones
title_fullStr Sentinel-1 Noise Suppression Algorithm for High-Wind-Speed Retrieval in Tropical Cyclones
title_full_unstemmed Sentinel-1 Noise Suppression Algorithm for High-Wind-Speed Retrieval in Tropical Cyclones
title_short Sentinel-1 Noise Suppression Algorithm for High-Wind-Speed Retrieval in Tropical Cyclones
title_sort sentinel 1 noise suppression algorithm for high wind speed retrieval in tropical cyclones
topic SAR
Sentinel-1
cross-polarization
denoising
wind speed
tropical cyclone (TC)
url https://www.mdpi.com/2072-4292/17/11/1827
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AT lihuawang sentinel1noisesuppressionalgorithmforhighwindspeedretrievalintropicalcyclones
AT weiweisun sentinel1noisesuppressionalgorithmforhighwindspeedretrievalintropicalcyclones
AT hongmeiwang sentinel1noisesuppressionalgorithmforhighwindspeedretrievalintropicalcyclones
AT wenjingjiang sentinel1noisesuppressionalgorithmforhighwindspeedretrievalintropicalcyclones
AT tianfeng sentinel1noisesuppressionalgorithmforhighwindspeedretrievalintropicalcyclones