Dhote et al. (2025) Unveiling the First Impressions of the Wide‐Swath Altimetry SWOT Mission Over the Ganga River, India

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Geophysical Research Letters
• Year: 2025
• Date: 2025-10-06
• Authors: Pankaj R. Dhote, Ankit Agarwal, Adrien Paris, Gaurish Singhal, Praveen K. Thakur, Hind Oubanas, Daniel Medeiros Moreira, Laëtitia Gal, Vaibhav Garg, Pramod Kumar, Raghavendra Pratap Singh, Stéphane Calmant
• DOI: 10.1029/2025gl115402

Research Groups

Not specified in the abstract.

Short Summary

This study evaluates the performance of Surface Water and Ocean Topography (SWOT) mission's node and raster products for river hydrodynamics over a 210 km stretch of the Ganga River, finding varying accuracies for water surface elevation and slope, with node products generally more accurate for WSE but raster products providing better spatial detail.

Objective

• To evaluate the performance of Surface Water and Ocean Topography (SWOT) mission's node and raster products for river hydrodynamics, specifically water surface elevation (WSE) and water surface slope (WSS), across a complex riverine environment.

Study Configuration

• Spatial Scale: Approximately 210 km stretch of the Ganga River, India.
• Temporal Scale: During the fast-sampling phase of the SWOT mission.

Methodology and Data

• Models used: Not applicable; the study evaluates satellite products rather than using a hydrological model.
• Data sources: SWOT node and raster products, GNSS-based continuous measurements, two in situ stations, and four altimetry virtual stations.

Main Results

• SWOT node products showed slightly better water surface elevation (WSE) accuracy than raster products, with root mean square errors (RMSEs) of 0.19 m (compared to GNSS), 0.09 m (compared to in situ station, Varanasi), and 0.88 m (compared to virtual stations).
• Quality filters applied to node products reduced their temporal resolution.
• Raster data effectively captured 2D WSE variability, thereby enhancing spatial sampling in wide river cross-sections.
• SWOT-derived water surface slopes (WSS) yielded mixed results across SWORD reaches, with an RMSE of 0.0254 m/km.
• Strong backscatter from the main river channel waters (mean +13.34 dB) was beneficial for river width retrieval.

Contributions

• This study provides a novel evaluation of SWOT node and raster products for river hydrodynamic applications over a significant and complex riverine environment (Ganga River, India).
• It quantifies the accuracy of SWOT-derived WSE and WSS using a comprehensive set of ground-truth data, including GNSS, in situ stations, and altimetry virtual stations.
• The analysis highlights the distinct advantages and limitations of node versus raster products, particularly regarding WSE accuracy, spatial sampling, and temporal resolution, contributing to a better understanding of SWOT's potential and challenges in varied river morphologies.

Funding

Not specified in the abstract.

Citation

@article{Dhote2025Unveiling,
  author = {Dhote, Pankaj R. and Agarwal, Ankit and Paris, Adrien and Singhal, Gaurish and Thakur, Praveen K. and Oubanas, Hind and Moreira, Daniel Medeiros and Gal, Laëtitia and Garg, Vaibhav and Kumar, Pramod and Singh, Raghavendra Pratap and Calmant, Stéphane},
  title = {Unveiling the First Impressions of the Wide‐Swath Altimetry SWOT Mission Over the Ganga River, India},
  journal = {Geophysical Research Letters},
  year = {2025},
  doi = {10.1029/2025gl115402},
  url = {https://doi.org/10.1029/2025gl115402}
}