Long-Term Validation of Wave Height Measurements from Altimeters

Queffeulou, P.

doi:10.1080/01490410490883478

Cited by 179 publications

(137 citation statements)

References 7 publications

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“…The coefficients for TOPEX in Table 2 are consistent with our earlier estimates (Ray and Beckley, 2003) within their error limits (which were previously ±0.014 on β 1 , not 0.0014 as stated by Queffeulou, 2004). Our new results for Jason-1 are not consistent with our previous results, but, as noted above, these were for IGDR data (and for a very small sample size of 368).…”

Section: Buoy-altimeter Statisticssupporting

confidence: 76%

“…Several aspects of Figure 12 where H s began drifting markedly, increasing by more than 30 cm in two years (e.g., Queffeulou, 2004). The sharp discontinuity in February 1999 was the result of switching to a second redundant altimeter aboard TOPEX.…”

Section: Buoy-altimeter Differences In Timementioning

confidence: 99%

“…At this writing, however, the full dataset has not been retracked, so only the MGDR-B data are used here. For the buoy-altimeter statistical comparisons below, the TOPEX data for part of 1997-1999 (repeat cycles 160-236) are not used because those wave data are known to have drifted markedly (e.g., Queffeulou, 2004).…”

Section: Datamentioning

confidence: 99%

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Calibration of Ocean Wave Measurements by the TOPEX, Jason-1, and Jason-2 Satellites

Ray

Beckley

2012

Marine Geodesy

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The calibration and validation of ocean wave height measurements by the TOPEX, Jason-1, and Jason-2 satellite altimeters is addressed by comparing the measurements internally among themselves and against independent wave measurements at moored buoys. The two six-month verification campaigns, when two of the satellites made near-simultaneous measurements along the same ground track, are invaluable for such work and reveal subtle aspects that otherwise might go undetected.The two Jason satellites are remarkably consistent; Topex reports waves generally 1-2% larger. External calibration is complicated by some systematic errors in the buoy data. We confirm a recent report by Durrant et al. that Canadian buoys underestimate significant wave heights by about 10% relative to U.S. buoys. Wave heights from all three altimetric satellites require scaling upwards by 5-6% to be consistent with U.S. buoys.

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Section: Buoy-altimeter Statisticssupporting

confidence: 76%

Section: Buoy-altimeter Differences In Timementioning

confidence: 99%

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Calibration of Ocean Wave Measurements by the TOPEX, Jason-1, and Jason-2 Satellites

Ray

Beckley

2012

Marine Geodesy

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“…As for Woolf et al, the calibration procedures used to correct the nominal altimeter derived wave heights to derive the climatology used in this study are described by Cotton (1998), Challenor and Cotton (2002) and Queffeulou (2004), and have been validated against the Australian waverider buoys by Hemer et al (2007). Table I summarizes the calibration equations and the periods for which each satellite provides a validated climatology (Note that Woolf et al (2002) Sporadic gaps in the climatology occur for a few grid squares in occasional months due to the sparse sampling by the altimeter.…”

mentioning

confidence: 99%

Variability and trends in the directional wave climate of the Southern Hemisphere

Hemer

Church

Hunter

2009

Intl Journal of Climatology

245

206

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The effect of interannual climate variability and change on the historic, directional wave climate of the Southern Hemisphere is presented. Owing to a lack of in situ wave observations, wave climate in the Southern Hemisphere is determined from satellite altimetry and global ocean wave models. Altimeter data span the period 1985 to present, with the exception of a 2‐year gap in 1989–1991. Interannual variability and trends in the significant wave height are determined from the satellite altimeter record (1991 to present), and the dominant modes of variability are identified using an empirical orthogonal function (EOF) analysis. Significant wave heights in the Southern Ocean are observed to show a strong positive correlation with the Southern Annular Mode (SAM), particularly during Austral autumn and winter months. Correlation between altimeter derived significant wave heights and the Southern Oscillation Index is observed in the Pacific basin, which is consistent with several previous studies. Variability and trends of the directional wave climate are determined using the ERA‐40 Waves Re‐analysis for the period 1980–2001. Significant wave height, mean wave period and mean wave direction data are used to describe the climate of the wave energy flux vector. An EOF analysis of the wave energy flux vector is carried out to determine the dominant modes of variability of the directional seasonal wave energy flux climate. The dominant mode of variability during autumn and winter months is strongly correlated to the SAM. There is an anti‐clockwise rotation of wave direction with the southward intensification of the Southern Ocean storm belt associated with the SAM. Clockwise rotation of flux vectors is observed in the Western Pacific Ocean during El‐Nino events. Directional variability of the wave energy flux in the Western Pacific Ocean has previously been shown to be of importance to sand transport along the south‐eastern Australian margin, and the New Zealand region. The directional variability of the wave energy flux of the Southern Ocean associated with the SAM is expected to be of importance to the wave‐driven currents responsible for the transport of sand along coastal margins in the Southern Hemisphere, in particular those on the Southern and Western coastal margins of the Australian continent. Copyright © 2009 Royal Meteorological Society

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“…Ocean (Gower, 1996). SWH estimates from the recent Jason-1 and Envisat altimeter missions had been tested using buoy and cross altimeter comparisons (Queffeulou, 2004). In the Gulf of Mexico,42,035 matchups between Topex/Poseidon and buoys showed RMS errors of 0.15-0.18 m, bias error on the order of 0.05 m, and correlation coefficients of 0.96 and 0.94 for Ku-band and C-band, respectively (Hwang et al, 1998).…”

mentioning

confidence: 99%

Validation of Significant Wave Height from Satellite Altimeter in the Seas around Korea and Error Characteristics

Park¹,

Woo²,

Lee³

et al. 2013

Korean Journal of Remote Sensing

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Oceanic surface waves are generated by winds blowing over the oceanic surface of which the strength depends on how strong, how long, and how far the winds blow (Kinsman, 1965;Knauss, 1996). Since the waves can travel far from their origin of propagation to over thousands of kilometers as swell, they can have remarkable influences on non-local remote coastal regions. Therefore, the waves at local coastal stations Abstract : Significant Wave Height (SWH) data measured by satellite altimeters (Topex/Poseidon, Jason-1, Envisat, and Jason-2) were validated in the seas around Korea by comparison with wave height measurements from marine meteorological buoy stations of Korea Meteorological Administration (KMA). A total of 1,070 collocation matchups between Ku-band satellite altimeter data and buoy data were obtained for the periods of the four satellites from 1992 to the present. In the case of C-band and S-band observations, 1,086 matchups were obtained and used to assess the accuracy of satellite SWH. Root-Mean-Square (RMS) errors of satellite SWH measured with Ku-band were evaluated to roughly 0.2 _ 2.1 m. Comparisons of the RMS errors and bias errors between different frequency bands revealed that SWH observed with Ku-band was much more accurate than other frequencies, such as C-band or S-band. The differences between satellite SWH and buoy wave height, satellite minus buoy, revealed some dependence on the magnitude of the wave height. Satellite SWH tended to be overestimated at a range of low wave height of less than 1 m, and underestimated for high wave height of greater than 2 m. Such regional characteristics imply that satellite SWH should be carefully used when employed for diverse purposes such as validating wave model results or data assimilation procedures. Thus, this study confirmed that satellite SWH products should be continuously validated for regional applications.Key Words : significant wave height, satellite altimeter, Ku-band, validation Korean Journal of Remote Sensing, Vol.29, No.6, 2013, pp.631~644 http://dx.doi.org/10.7780/kjrs.2013 -6 31 -

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Long-Term Validation of Wave Height Measurements from Altimeters

Cited by 179 publications

References 7 publications

Calibration of Ocean Wave Measurements by the TOPEX, Jason-1, and Jason-2 Satellites

Calibration of Ocean Wave Measurements by the TOPEX, Jason-1, and Jason-2 Satellites

Variability and trends in the directional wave climate of the Southern Hemisphere

Validation of Significant Wave Height from Satellite Altimeter in the Seas around Korea and Error Characteristics

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