Estimation of Contamination of ERS-2 and POSEIDON Satellite Radar Altimetry Close to the Coasts of Australia

Deng, Xiaoli; Featherstone, Will; Hwang, Cheinway; Berry, P. A. M.

doi:10.1080/01490410214990

Cited by 105 publications

(63 citation statements)

References 19 publications

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“…This is more challenging than using geodetic-only techniques because of interannual and decadal sea level variability due to a strong El Nino Southern Oscillation signal along the Western Australian coast [e.g., Amin, 1993;Nidheesh et al, 2013], and additional uncertainty of radar altimetry close to the coasts [e.g., Deng et al, 2002].…”

Section: Differential Rlr and Altimetrymentioning

confidence: 99%

Nonlinear subsidence at Fremantle, a long‐recording tide gauge in the Southern Hemisphere

et al. 2015

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A combination of independent evidence (continuous GPS, repeat geodetic leveling, groundwater abstraction, satellite altimetry, and tide gauge (TG) records) shows that the long‐recording Fremantle TG has been subsiding in a nonlinear way since the mid‐1970s due to time‐variable groundwater abstraction. The vertical land motion (VLM) rates vary from approximately −2 to −4 mm/yr (i.e., subsidence), thus producing a small apparent acceleration in mean sea level computed from the Fremantle TG records. We exemplify that GPS‐derived VLM must be geodetically connected to the TG to eliminate the commonly used assumption that there is no differential VLM when the GPS is not colocated with the TG. In the Perth Basin, we show that groundwater abstraction can be used as a diagnostic tool for identifying nonlinear VLM that is not evident in GPS time series alone.

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Section: Differential Rlr and Altimetrymentioning

confidence: 99%

Nonlinear subsidence at Fremantle, a long‐recording tide gauge in the Southern Hemisphere

et al. 2015

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“…To reduce the effect of low-amplitude samples in front of the leading edge, the squares of the sample values are used in the computation. The equations used to compute A, W and COG are given in Deng et al [2002].…”

Section: A2 Threshold Retrackingmentioning

confidence: 99%

“…Deng et al, 2002] around the Australian coast have been categorized, which is needed to choose the appropriate retracking algorithm. A detailed example of typical waveform categorization is given here from one ascending ground track 21636 off the northwest Australian coast (Figure 6).…”

Section: Waveform Classificationmentioning

confidence: 99%

“…The middle-gate along-track footprint for 20 Hz measurements varies from 8.5 km to 15 km for ERS-2 depending on the presence of surface roughness [cf. Chelton et al, 2001, p. 36;Deng et al, 2002]. As this footprint gets closer to the coastline, the slant range to reflectively higher land may be shorter than that from the nadir ocean surface.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, ERS-2 altimeter SSHs can be contaminated by these factors up to a maximum distance of $22 km offshore the Australian coast [Deng et al, 2002]. As such, many scientists avoid the use of SSHs in coastal regions [e.g., Nerem, 1995], typically beyond 20-50 km of the coast [Strub and James, 1997].…”

Section: Introductionmentioning

confidence: 99%

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A coastal retracking system for satellite radar altimeter waveforms: Application to ERS‐2 around Australia

2006

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[1] Satellite radar altimeter-derived sea surface heights (SSH) are in error in coastal regions due, in part, to the complex nature of echoes returned from rapidly varying land and sea surfaces. This paper presents improved altimeter-derived SSH results in Australian coastal regions using the waveform retracking technique, which reprocesses the waveform data through a ''coastal retracking system''. The system, based upon a systematic analysis of satellite radar altimeter waveforms around Australia, improves SSH data from several retrackers depending on the waveforms' characteristics. Central to the system is the use of two techniques: the least squares fitting and the threshold retracking algorithms. To overcome the problem of fading noise, the fitting algorithm has been developed to include a weighted iterative scheme. The retrackers include five fitting models and the threshold method with varying threshold levels. A waveform classification procedure has also been developed, which enables the waveforms to be sorted and then retracked by an appropriate retracker. Two cycles of 20-Hz waveform data from ERS-2 have been reprocessed using this system to obtain the improved SSH estimates. Using the AUSGeoid98 gravimetric geoid model as a quasi-independent reference, the system improves SSH estimates from beyond $22 km to beyond $5 km from the coastline.Citation: Deng, X., and W. E. Featherstone (2006), A coastal retracking system for satellite radar altimeter waveforms: Application

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Satellite Altimetry: Principles and Applications in Earth Sciences

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Blumstein

Cazenave

et al. 2017

Wiley Encyclopedia of Electrical and Electronics Engineering

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Satellite altimetry is a radar technique measuring the topography of the Earth surface. It was initially designed for the measuring of the topography of the sea surface with reference to an ellipsoid and for the determination of the marine geoid. It also provided valuable information on the ocean circulation. With the improvement of the orbit accuracy from the meter to the centimeter level, satellite altimetry has become a key measurement to estimate sea level variations from regional to global scales. Satellite altimetry is mostly used over the ocean to measure the surface geostrophic currents, eddy structures, wave heights, and the propagation of oceanic Kelvin and Rossby waves. Altimetry has also demonstrated a strong potential for ice and hydrology studies and is now commonly used for the monitoring of the Arctic and Antarctic ice sheets topography and of terrestrial surface water levels.

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Estimation of Contamination of ERS-2 and POSEIDON Satellite Radar Altimetry Close to the Coasts of Australia

Cited by 105 publications

References 19 publications

Nonlinear subsidence at Fremantle, a long‐recording tide gauge in the Southern Hemisphere

Nonlinear subsidence at Fremantle, a long‐recording tide gauge in the Southern Hemisphere

A coastal retracking system for satellite radar altimeter waveforms: Application to ERS‐2 around Australia

Satellite Altimetry: Principles and Applications in Earth Sciences

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