Evaluation of Coastal Sea Level Offshore Hong Kong from Jason-2 Altimetry

Xu, Xiangde; Birol, Florence; Cazenave, Anny

doi:10.3390/rs10020282

Cited by 27 publications

(18 citation statements)

References 32 publications

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“…Both the missions provide valid performance due to our numerical test and the agreement is slightly better for in situ/SARAL than for in situ/HY-2A. We also calculated the correlation coefficients for the tide gauge sites used for validation in the recent published studies [28,29]. Four UHSLC sites (Los Angeles, CA; Cape May, NJ; Ko Lak; Hong Kong) with required data series were selected due to the time-scope repetition with HY-2A and SARAL.…”

Section: Validation With Tide Gauge Measurementsmentioning

confidence: 86%

HY-2A Altimeter Data Initial Assessment and Corresponding Two-Pass Waveform Retracker

Zhang

Jin

et al. 2018

Remote Sensing

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The accuracy and resolution of the marine gravity field derived from multisatellite altimeter data sets mainly depend on the corresponding range precision and spatial distribution. Here, we preliminarily investigate the performance of HY-2A altimeter data by analyzing cross-mission sea surface height discrepancies with SARAL/AltiKa and calculating correlation coefficients with respect to tide gauge measurements. We also explore the improved range precision that can be achieved using a two-pass weighted least squares retracker which was proposed for the purpose of optimal gravity field recovery. Firstly, both the exact repetitive mission and the geodetic mission for HY-2A provide new track orientations and different data coverage for recovering the marine gravity field, and these dense geographical distributions are more greatly attributed to the geodetic mission in recent years. Secondly, HY-2A provides reliable sea surface height measurements based on exterior verifications by SARAL/AltiKa geophysical data records and tide gauge measurements, although the accuracy level is slightly lower than SARAL/AltiKa. Another more exciting finding is that the statistics of along-track sea surface heights in one-second intervals show that the two-pass retracking does further improve the range precision by a factor of 1.6 with respect to 20 Hz retracked results in sensor data records. In conclusion, the HY-2A mission can substantially improve the global accuracy and resolution of the marine gravity field and will reveal new tectonic features such as microplates, abyssal hill fabric, and new uncharted seamounts on the ocean floor.

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Section: Validation With Tide Gauge Measurementsmentioning

confidence: 86%

HY-2A Altimeter Data Initial Assessment and Corresponding Two-Pass Waveform Retracker

Zhang

Jin

et al. 2018

Remote Sensing

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“…Some results are reported here, in which the sea level for a certain cycle is the average of all the valid measurements within ≤10 distance from the coast. Interested readers can refer to [41] for more details.…”

Section: Resultsmentioning

confidence: 99%

“…In the Hong Kong offshore case study, we find that the coastal sea level trend is about twice as much as the one observed further offshore (which can be inferred as +2.7 mm/yr. from the ESA Sl_CCI product [41]). It suggests that in the Hong Kong region, the short-term sea level trend significantly increases when approaching the coast.…”

Section: Conclusion and Prospectivementioning

confidence: 99%

Coastal Altimetry: A Promising Technology for the Coastal Oceanography Community

Xu¹,

Ke²,

Xu³

et al. 2020

Estuaries and Coastal Zones - Dynamics and Response to Environmental Changes

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Satellite altimetry has been one of the most important implements for physical oceanographers. The conventional altimeter is best performed over open ocean surface, yet there are many attempts to exploit the potential of altimetry in coastal zone in the last decade. To achieve a high performance for coastal altimetry is a multi-fold effort: the more sophisticated instrument concepts, the smarter onboard trackers, the more expert data editing criteria, the more specific retracking algorithms, the more advanced error correction methods, etc. In this chapter, each of the above aspects is described in detail, and some representative works in the altimetry community are reviewed. Particularly, the coastal altimetry offshore Hong Kong is addressed as a case study to demonstrate the potential of the new technology. In the conclusive session, some prospects for the coastal oceanography community are presented.

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“…A table is published in Cipollini et al (2017) and a regularly updated version is available at http://www.coastalt.eu/#datasets. Several studies compared these data sets with independent measurements (e.g., Gómez-Enri et al, 2016;Vu et al, 2018;Xu et al, 2018). Quality assessments for Sentinel-3A and CryoSat-2 (Bonnefond et al, 2018a;Fenoglio et al, 2019) and AltiKa data (Bonnefond et al, 2018b) have also been performed.…”

Section: Level 3 Altimetry Datasetsmentioning

confidence: 99%

Requirements for a Coastal Hazards Observing System

et al. 2019

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Coastal zones are highly dynamical systems affected by a variety of natural and anthropogenic forcing factors that include sea level rise, extreme events, local oceanic and atmospheric processes, ground subsidence, etc. However, so far, they remain poorly monitored on a global scale. To better understand changes affecting world coastal zones and to provide crucial information to decision-makers involved in adaptation to and mitigation of environmental risks, coastal observations of various types need to be collected and analyzed. In this white paper, we first discuss the main forcing agents acting on coastal regions (e.g., sea level, winds, waves and currents, river runoff, sediment supply and transport, vertical land motions, land use) and the induced coastal response (e.g., shoreline position, estuaries morphology, land topography at Frontiers in Marine Science | www.frontiersin.org 1 July 2019 | Volume 6 | Article 348Benveniste et al.Requirements for a Coastal Zone Observing System the land-sea interface and coastal bathymetry). We identify a number of space-based observational needs that have to be addressed in the near future to understand coastal zone evolution. Among these, improved monitoring of coastal sea level by satellite altimetry techniques is recognized as high priority. Classical altimeter data in the coastal zone are adversely affected by land contamination with degraded range and geophysical corrections. However, recent progress in coastal altimetry data processing and multisensor data synergy, offers new perspective to measure sea level change very close to the coast. This issue is discussed in much detail in this paper, including the development of a global coastal sea-level and sea state climate record with mission consistent coastal processing and products dedicated to coastal regimes. Finally, we present a new promising technology based on the use of Signals of Opportunity (SoOp), i.e., communication satellite transmissions that are reutilized as illumination sources in a bistatic radar configuration, for measuring coastal sea level. Since SoOp technology requires only receiver technology to be placed in orbit, small satellite platforms could be used, enabling a constellation to achieve high spatio-temporal resolutions of sea level in coastal zones.

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Evaluation of Coastal Sea Level Offshore Hong Kong from Jason-2 Altimetry

Cited by 27 publications

References 32 publications

HY-2A Altimeter Data Initial Assessment and Corresponding Two-Pass Waveform Retracker

HY-2A Altimeter Data Initial Assessment and Corresponding Two-Pass Waveform Retracker

Coastal Altimetry: A Promising Technology for the Coastal Oceanography Community

Requirements for a Coastal Hazards Observing System

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