English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Satellite altimetry has revolutionized river monitoring, particularly for hydrologists working on river flow monitoring in sparsely or ungauged areas. Despite this, there&#x0027;s a lack of a comprehensive evaluation of radar and lidar altimeters with varying sensor specifications for river water level retrieval, seasonal change characterization, and water surface slope (WSS) using gauged long-term water level and global navigation satellite system (GNSS) data. This study addresses this gap by combined evaluation of radar (ENVISAT to Sentinel-3) and lidar (ICESat-1, ICESat-2) altimeters along the Ganga River, from Prayagraj to Varanasi. We found that, all the radar altimetry missions showed better accuracy for water level retrievals (R2 &gt; &#x003D; 0.8; RMSE 0.11 to 1.16 m) and water level change quantification (RMSE 0.59 m). However, Sentinel-3 with SAR acquisition mode outperformed (RMSE 0.11 to 0.14 m) all the radar missions having low resolution mode. Despite lidar missions' high vertical accuracy, they show relatively lower accuracy in water level time series generation due to non-repeating characteristics. In contrary, ICESat-2 demonstrates potential in capturing spatial and seasonal variability of WSS, enhancing the accuracy of SWOT discharge products when combined with SWOT River database (SWORD). This study provides a comprehensive baseline for end-users interested in utilizing radar and lidar missions for various hydrological applications, including river discharge estimation. Moreover, the studied river reach shares the SWOT calibration orbit, allowing the utilization of generated satellite and in-situ databases for the effective evaluation of SWOT measurements.

ieee journal of selected topics in applied earth observations and remote sensing

River Water Level and Water Surface Slope Measurement from Spaceborne Radar and Lidar Altimetry: Evaluation and Implications for Hydrological Studies in the Ganga River