The Surface Water and Ocean Topography Mission: A Breakthrough in Radar Remote Sensing of the Ocean and Land Surface Water

Fu, Lee‐Lueng; Pavelsky, Tamlin; Cretaux, Jean‐Francois; Morrow, Rosemary; Farrar, J. Thomas; Vaze, Parag; Sengenes, Pierre; Vinogradova‐Shiffer, Nadya; Sylvestre‐Baron, Annick; Picot, Nicolas; Dibarboure, Gerald

doi:10.1029/2023gl107652

Cited by 36 publications

(7 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Arrival of early data from the SWOT mission has shown that the SSH variability observed by the satellite exceeds mission requirements in the submesoscale band at wavelengths below 25 km (Figure 1 in [3]). Special attention in SWOT calibration has focused on removing systematic errors caused by the uncertainties in the geometry and orientation of the on-board interferometer, which provides the largest contribution to the SWOT error budget [7].…”

Section: Summary and Discussionmentioning

confidence: 99%

“…However, it still keeps its superior skill in retrieving the true state at a significantly better (2 times) level (Figure 6). It is noteworthy that such situations (large background errors at small scales) are unlikely in the open ocean, because both modeling [39] and the latest SWOT observations [3] indicate that the SSH spectrum falls steeply with the wavenumber so that respective background errors should barely exceed 5 cm at scales below 5 km.…”

Section: Computational Efficiencymentioning

confidence: 99%

“…The Surface Water and Ocean Topography (SWOT [1][2][3]), the Coastal and Ocean Measurement with Precise and Innovative Radar Altimeter (COMPIRA [4]), and the Guanlan [5] missions were designed to deliver high-resolution maps of ocean surface topography using radar interferometry. The SWOT satellite was launched on 16 December 2022, initially into a fast (1-day repeat cycle) sampling orbit for calibration, which later (on 21 July 2023) transitioned to an operational (science) orbit having a longer (21-day) repeat cycle.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Block-Circulant Approximation of the Precision Matrix for Assimilating SWOT Altimetry Data

Yaremchuk,

Beattie,

Panteleev

et al. 2024

Remote Sensing

View full text Add to dashboard Cite

The recently deployed Surface Water and Ocean Topography (SWOT) mission for the first time has observed the ocean surface at a spatial resolution of 1 km, thus giving an opportunity to directly monitor submesoscale sea surface height (SSH) variations that have a typical magnitude of a few centimeters. This progress comes at the expense of the necessity to take into account numerous uncertainties in calibration of the quality-controlled altimeter data. Of particular importance is the proper filtering of spatially correlated errors caused by the uncertainties in geometry and orientation of the on-board interferometer. These “systematic” errors dominate the SWOT error budget and are likely to have a notable signature in the SSH products available to the oceanographic community. In this study, we explore the utility of the block-circulant (BC) approximation of the SWOT precision matrix developed by the Jet Propulsion Laboratory for assessment of a mission’s accuracy, including the possible impact of the systematic errors on the assimilation of the wide-swath altimeter data into numerical models. It is found that BC approximation of the precision matrix has sufficient (90–99%) accuracy for a wide range of significant wave heights of the ocean surface, and, therefore, could potentially serve as an efficient preconditioner for data assimilation problems involving altimetry observations by space-borne interferometers. An extensive set of variational data assimilation (DA) experiments demonstrates that BC approximation provides more accurate SSH retrievals compared to approximations, assuming a spatially uncorrelated observation error field as is currently adopted in operational DA systems.

show abstract

Section: Summary and Discussionmentioning

confidence: 99%

Section: Computational Efficiencymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Block-Circulant Approximation of the Precision Matrix for Assimilating SWOT Altimetry Data

Yaremchuk,

Beattie,

Panteleev

et al. 2024

Remote Sensing

View full text Add to dashboard Cite

show abstract

“…The Surface Water and Ocean Topography (SWOT) satellite mission was designed to resolve SSHA at wavelengths down to ~15 km [4,5]. A recent study shows that SWOT's 2 km 2 data product appears to achieve about three times better resolution [6]. The 2 km data product is derived from 250 m native grid data.…”

Section: Introductionmentioning

confidence: 99%

Sea Surface Height Wavenumber Spectrum from Airborne Interferometric Radar Altimeter

He,

Xu,

Sun

et al. 2024

Remote Sensing

View full text Add to dashboard Cite

The proposed “Guanlan” ocean science satellite, led by China’s Laoshan Laboratory, includes an interferometric radar altimeter (IRA) as a key payload. As an integral part of its development, an airborne IRA experiment was conducted on 6 November 2021, with a flight path of approximately 90 km in the South China Sea. This study investigates the IRA’s ability to observe ocean sea surface height (SSH) across scales ranging from meters to mesoscale. The sea surface height anomaly (SSHA) of the IRA is aligned with the SSHA of the AVISO at scales greater than 30 km, but also demonstrates the ability to capture small-scale SSHA changes in two dimensions. We analyzed wavenumber spectra of SSHA obtained from the airborne IRA, ICESat-2, and SARAL/AltiKa satellite for this region. The results show a good agreement in power spectral density (PSD) levels between ICESat-2, SARAL/AltiKa and IRA at scales larger than 30 km. Within the submesoscale range of 1–10 km, the IRA SSHA spectrum exhibits a distinctly negative slope and the lowest energy level. The minimum PSD level of the IRA fell in the range of 10−4–10−3 m2/cycle/km, at scales around 1 km, which is more than an order of magnitude lower than that of ICESat-2, forming a spectral gap that is in agreement with the theoretical expectation. Furthermore, IRA-derived wave direction and significant wave height matched well with the MFWAM wave data. The results of this study underscore the considerable potential of airborne IRA in capturing SSHA across a range of scales, from oceanic waves to submesoscale.

show abstract

“…The SWOT mission was launched in December 2022 to measure the high-resolution, 2-dimensional sea surface height (SSH) field based on the Ka-band radar interferometer (KaRIn) instrument (Fu et al, 2024;Morrow et al, 2019). Compared to the ∼50-km noise floor achieved by the conventional nadir altimeters, KaRIn has an order-of-magnitude lower noise floor at 5-km wavelength and, averaged globally, its rms noise level is estimated to be around 0.25 cm on a 1 km-by-1 km grid posting (Fu et al, 2024).…”

Section: Introductionmentioning

confidence: 99%

Seasonal and Fortnight Variations in Internal Solitary Waves in the Indonesian Seas From the SWOT Measurements

Qiu,

Chen,

Wang

et al. 2024

JGR Oceans

Self Cite

View full text Add to dashboard Cite

Using the wide‐swath sea surface height (SSH) data from the 1‐day repeat calibration/validation phase of the Surface Water and Ocean Topography (SWOT) mission, we explored fine‐scale evolution of nonlinear internal solitary waves (ISWs) in the Banda/Molucca Seas in the Indonesian Archipelagos. Generated in the Ombai Strait and Lifamatola Passage through semidiurnal tide‐topography interaction, respectively, ISWs in the Banda/Molucca Seas have a SSH amplitude of 10–20 cm and exhibit multiple wave packets with the leading wave crest followed by a series of rank‐ordered secondary wave crests. Due to nonlinearity, the ISWs are observed to propagate northward at a speed faster than the regional mode‐1 internal gravity waves and their amplitudes are modulated fortnightly following the regional spring‐neap tidal cycle. On longer timescale, the observed ISW amplitudes are controlled by seasonal upper ocean stratification changes with a weaker stratification favoring a larger amplitude. By converting the SWOT‐measured SSH data to the interior ocean pressure signals, we quantified the depth‐integrated energy flux associated with the northward‐propagating ISWs to be 5 and 2 kW m−1 in the central Banda and Molucca Seas, respectively. Comparisons with past studies indicate that the ISWs contribute to close to 100% and 40% of the tidally‐induced, northward energy fluxes, respectively, across the Banda and Molucca Seas.

show abstract

The Surface Water and Ocean Topography Mission: A Breakthrough in Radar Remote Sensing of the Ocean and Land Surface Water

Cited by 36 publications

References 41 publications

Block-Circulant Approximation of the Precision Matrix for Assimilating SWOT Altimetry Data

Block-Circulant Approximation of the Precision Matrix for Assimilating SWOT Altimetry Data

Sea Surface Height Wavenumber Spectrum from Airborne Interferometric Radar Altimeter

Seasonal and Fortnight Variations in Internal Solitary Waves in the Indonesian Seas From the SWOT Measurements

Contact Info

Product

Resources

About