Validation of ocean wind and wave data using triple collocation

Caires, S.; Sterl, Andreas

doi:10.1029/2002jc001491

Cited by 180 publications

(172 citation statements)

References 21 publications

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“…With the improvising of satellite altimeters, the respective blunder for the satellite altimeter has been downsized if compared with the ground-truth buoy, thus the linear-regression method is used for inter-comparison purposes (Durrant et al, 1987). Based on the previous study has concluded the relative error between the satellite altimeter and the ground-truth buoy are relatively equal (Caires and Sterl, 2003). The Ground-truth buoy can be used as a bench-mark for quality control upon the instrument errors and for the affirmation part (Zhoa el al., 2012).…”

Section: Resultsmentioning

confidence: 99%

Reliability of Wind Speed Data From Satellite Altimeter to Support Wind Turbine Energy

Uti

Din

Omar

2017

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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ABSTRACT:Satellite altimeter has proven itself to be one of the important tool to provide good quality information in oceanographic study. Nowadays, most countries in the world have begun in implementation the wind energy as one of their renewable energy for electric power generation. Many wind speed studies conducted in Malaysia using conventional method and scientific technique such as anemometer and volunteer observing ships (VOS) in order to obtain the wind speed data to support the development of renewable energy. However, there are some limitations regarding to this conventional method such as less coverage for both spatial and temporal and less continuity in data sharing by VOS members. Thus, the aim of this research is to determine the reliability of wind speed data by using multi-mission satellite altimeter to support wind energy potential in Malaysia seas. Therefore, the wind speed data are derived from nine types of satellite altimeter starting from year 1993 until 2016. Then, to validate the reliability of wind speed data from satellite altimeter, a comparison of wind speed data form ground-truth buoy that located at Sabah and Sarawak is conducted. The validation is carried out in terms of the correlation, the root mean square error (RMSE) calculation and satellite track analysis. As a result, both techniques showing a good correlation with value positive 0.7976 and 0.6148 for point located at Sabah and Sarawak Sea, respectively. It can be concluded that a step towards the reliability of wind speed data by using multi-mission satellite altimeter can be achieved to support renewable energy.

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Section: Resultsmentioning

confidence: 99%

Reliability of Wind Speed Data From Satellite Altimeter to Support Wind Turbine Energy

Uti

Din

Omar

2017

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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“…Comparisons of the NCEPR and ERA40 near-surface winds with satellite, buoy, research-vessel and land station winds showed that reanalysis near-surface winds were biased low, particularly in tropical latitudes and for high wind speeds (Swail and Cox, 2000;Smith et al, 2001;Kubota et al, 2002;Caires and Sterl, 2003;Goswami and Sengupta, 2003;Wu and Xie, 2003;Yuan, 2004;Jiang et al, 2005).…”

Section: Ncep-ncar and Ecmwf Reanalysis (Ncepr And Era40) Windsmentioning

confidence: 99%

Trends in ship wind speeds adjusted for observation method and height

Thomas

Kent

Swail

et al. 2007

Intl Journal of Climatology

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Globally averaged wind speeds from archived ship reports show an increasing trend since the 1940s, which previous studies attributed to the gradual shift from visually estimated to anemometer-measured winds, and an increase in mean anemometer height. To test this hypothesis, adjustments to account for these changes were applied to individual ship wind observations in the International Comprehensive Ocean-Atmosphere Data Set (ICOADS). Annual means calculated from adjusted reports were compared to reanalysis near-surface winds in consistently well-sampled regions for the period 1958-2002.The adjustments to individual ship wind reports for known biases improve the homogeneity over the entire period and remove trends, prior to the early 1980s. However, for the 21-year period 1982-2002, trends remain in the annual mean spatially averaged adjusted winds, of 0.4 ms −1 decade −1 (6% decade −1 ) for estimated speeds, and of 0.2 ms −1 decade −1 (3% decade −1 ) for measured speeds. In contrast, co-located reanalysis near-surface wind speeds show little change, 1% decade −1 or less. Anemometers were installed on increasing numbers of ships during the period of study, even as many of these ships continued to report estimated winds. Part of the trend in estimated wind speeds is probably spurious, most likely a result of observers being increasingly influenced by readings from anemometers located well above 10-m. This influence is indicated by the gradual reduction in the tendency to underestimate nighttime marine winds. Results confirm earlier findings that reanalysis near-surface winds were biased low. The paper summarizes methods that could be employed to account for remaining inhomogeneities and thereby improve the quality of the marine wind climate record.

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“…In fact, the appropriate fitting method depends on the relative magnitudes of the measurement errors, or at least their ratio (Cheng and Van Ness, 1999), and orthogonal regression is warranted only if this ratio is near unity, thus treating both variables symmetrically-an approach that appears more justified for the altimeter-altimeter fits of Section 3. Nonetheless, several studies employing triple-collocation analyses (Caires and Sterl, 2003;Abdalla et al, 2011) Jason-2 data RMA yields a slope β 1 = 1.0519 versus 1.0528 for orthogonal regression, a difference of little consequence and less than the standard error ( Table 2). …”

Section: Buoy-altimeter Statisticsmentioning

confidence: 99%

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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Validation of ocean wind and wave data using triple collocation

Cited by 180 publications

References 21 publications

Reliability of Wind Speed Data From Satellite Altimeter to Support Wind Turbine Energy

Reliability of Wind Speed Data From Satellite Altimeter to Support Wind Turbine Energy

Trends in ship wind speeds adjusted for observation method and height

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

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