Analysis of Sentinel-3 SAR altimetry waveform retracking algorithms for deriving temporally consistent water levels over ice-covered lakes

Shu, Song; Liu, Hongxing; Beck, Richard; Frappart, Frédéric; Korhonen, Johanna; Xu, Min; Yang, Bo; Hinkel, Kenneth M.; Huang, Yan; Yu, Bo

doi:10.1016/j.rse.2020.111643

Cited by 52 publications

(60 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another possibility is the analysis of the radar altimetry waveform to detect the signature of open water and ice in the radar altimeter footprint. In a recent study, the signature of ice was detected in the waveforms from Sentinel-3A, a recently launched altimetry mission operating in Synthetic Aperture Radar (SAR) mode, with the presence of a secondary maximum [49].…”

Section: Discussionmentioning

confidence: 99%

“…Sentinel-3A and 3B have been operating in SAR mode with greater along-track spatial resolution. They already demonstrated very strong capabilities for better discriminating the surface states of the lakes [49]. Due to the coarse spatial coverage of altimetry ground-tracks, even at high latitudes, the monitoring of the subarctic lakes water levels would benefit the combination of the data from the different altimetry missions operating simultaneously, not only from the 10 (Topex/Poseidon, Jason-1/2/3), 27 (Sentinel-3A and B) and 35 (ERS-1/2, ENVISAT, SARAL) -day repeat orbits, but also from Cryosat-2, first mission to operate in LRM, SAR, and SAR interferometry (SARin) modes, long-term (369 days) repeat orbit and from the lidar altimetry missions ICESat and ICESat-2.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Improving the Estimation of Water Level over Freshwater Ice Cover using Altimetry Satellite Active and Passive Observations

et al. 2020

Self Cite

View full text Add to dashboard Cite

Owing to its temporal resolution of 10-day and its polar orbit allowing several crossings over large lakes, the US National Aeronautics and Space Administration (NASA) and the French Centre National d’Etudes Spatiales (CNES) missions including Topex/Poseidon, Jason-1/2/3 demonstrated strong capabilities for the continuous and long-term monitoring (starting in 1992) of large and medium-sized water bodies. However, the presence of heterogeneous targets in the altimeter footprint, such as ice cover in boreal areas, remains a major issue to obtain estimates of water level over subarctic lakes of similar accuracy as over other inland water bodies using satellite altimetry (i.e., R ≥ 0.9 and RMSE ≤ 10 to 20 cm when compared to in-situ water stages). In this study, we aim to automatically identify the Jason-2 altimetry measurements corresponding to open water, ice and transition (water-ice) to improve the estimations of water level during freeze and thaw periods using only the point measurements of open water. Four Canadian lakes were selected to analyze active (waveform parameters) and passive (brightness temperature) microwave data acquired by the Jason-2 radar altimetry mission: Great Slave Lake, Lake Athabasca, Lake Winnipeg, and Lake of the Woods. To determine lake surface states, backscattering coefficient and peakiness at Ku-band derived from the radar altimeter waveform and brightness temperature at 18.7 and 37 GHz measured by the microwave radiometer contained in the geophysical data records (GDR) of Jason-2 were used in two different unsupervised classification techniques to define the thresholds of discrimination between open water and ice measurements. K-means technique provided better results than hierarchical clustering based upon silhouette criteria and the Calinski-Harabz index. Thresholds of discrimination between ice and water were validated with the Normalized Difference Snow Index (NDSI) snow cover products of the MODIS satellite. The use of open water threshold resulted in improved water level estimation compared to in situ water stages, especially in the presence of ice. For the four lakes, the Pearson coefficient (r) increased on average from about 0.8 without the use of the thresholds to more than 0.90. The unbiased RMSE were generally lower than 20 cm when the threshold of open water was used and more than 22 cm over smaller lakes, without using the thresholds.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Improving the Estimation of Water Level over Freshwater Ice Cover using Altimetry Satellite Active and Passive Observations

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…Cretaux et al (2018) evaluated Sentinel-3 and Jason-3 over Lake Issykkul ( 6236 km 2 ), and found that both missions achieved a very low RMSE of 3 cm with the Ocean retracker. Shu et al (2020) assessed the performance of the Sentinel-3 SAR retrackers over fifteen lakes, and they reported that the SAR Altimetry Mode Studies and Applications -3 (SAMOSA-3) retracker has the lowest mean RMSE of 8.08 cm.…”

Section: Introductionmentioning

confidence: 99%

“…Hertta operated by Finnish Environment Institute (SYKE) (http://www.syke.fi/fi-FI/Avoin_tieto/Ymparistotietojarjestelmat), the SMHI (Swedish Meteorological and Hydrological Institute) website (http://vattenwebb.smhi.se/station/), the Canada Real-time Hydrometric Data Website (https://wateroffice.ec.gc.ca/ mainmenu/real_time_data_index_e.html), and the Center for Operational Oceanographic Products and Services (https://tidesandcurrents.noaa.gov/) operated by NOAA. These gauge stations measure the water-equivalent lake levels when the lake is ice-covered (Shu et al, 2020). Note that the gauge data are referenced to different datums.…”

Section: Introductionmentioning

confidence: 99%

“…The SRAL works primarily on the Synthetic Aperture Radar (SAR) mode with the Low Resolution Mode (LRM) as a back-up (Sentinel-3-Team, 2017). Four retrackers are used in the SAR mode to produce elevation measurements, including SAR Altimetry Mode Studies and Applications -3 (SAMOSA-3), Offset Center of Gravity (OCOG), Sea-Ice, and Ice-Sheet (Shu et al, 2020). The OCOG (also known as Ice1)…”

mentioning

confidence: 99%

See 1 more Smart Citation

Evaluation of Historic and Operational Satellite Radar Altimetry Missions for Constructing Consistent Long-term Lake Water Level Records

Song¹,

Liu²,

Beck³

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. Thirteen satellite missions have been launched since 1985, with different types of radar altimeters onboard. This study intends to make a comprehensive evaluation of historic and currently operational satellite radar altimetry missions for lake water level retrieval over the same set of lakes and to develop a strategy for constructing consistent long-term water level records for inland lakes at global scale. The lake water level estimates produced by different retracking algorithms (retrackers) of the satellite missions were compared with the gauge measurements over twelve lakes in four countries. The performance of each retracker was assessed in terms of the data missing rate, the correlation coefficient r, the bias, and the Root Mean Square Error (RMSE) between the altimetry-derived lake water level estimates and the concurrent gauge measurements. The results show that the model-free retrackers (e.g. OCOG/Ice-1/Ice) outperform the model-based retrackers for all missions, particularly over small lakes. Among the satellite altimetry missions, Sentinel-3 gave the best results, followed by SARAL. ENVISat has slightly better lake water level estimates than Jason-1 and -2, but its data missing rate is higher. For small lakes, ERS-1 and ERS-2 missions provided more accurate lake water level estimates than Topex/Poseidon mission. In contrast, for large lakes Topex/Poseidon is a better option due to its lower data missing rate and shorter repeat cycle. GeoSat and GeoSat Follow-On (GFO) both have extremely high data missing rate. Although several contemporary radar altimetry missions provide more accurate lake level estimates than GFO, GeoSat was the sole radar altimetry mission between 1985 and 1990 that provided the lake water level estimates. With a full consideration of the performance and the operational duration, the best strategy for constructing long-term lake water level records should be a two-step bias correction and normalization procedure. In the first step, use Jason-2 as the initial reference to estimate the systematic biases with Topex/Poseidon, Jason-1 and Jason-3 and then normalize them to form a consistent Topex/Poseidon-Jason series. Then, use Topex/Poseidon-Jason series as the reference to estimate and remove systematic biases with other radar altimetry missions to construct consistent long-term lake water level series for ungauged lakes.

show abstract

Inland Waters Unveiled: Exploring Water Surface Elevation in Peninsular Malaysia Using Satellite Sentinel-3 SRAL Altimeter

Abdul Majid,

Idris,

Md Reba

et al. 2024

Springer Proceedings in Physics

View full text Add to dashboard Cite

Analysis of Sentinel-3 SAR altimetry waveform retracking algorithms for deriving temporally consistent water levels over ice-covered lakes

Cited by 52 publications

References 56 publications

Improving the Estimation of Water Level over Freshwater Ice Cover using Altimetry Satellite Active and Passive Observations

Improving the Estimation of Water Level over Freshwater Ice Cover using Altimetry Satellite Active and Passive Observations

Evaluation of Historic and Operational Satellite Radar Altimetry Missions for Constructing Consistent Long-term Lake Water Level Records

Inland Waters Unveiled: Exploring Water Surface Elevation in Peninsular Malaysia Using Satellite Sentinel-3 SRAL Altimeter

Contact Info

Product

Resources

About