Technical note: Impacts of collocation window on the accuracy of altimeter/buoy wind-speed comparison-a simulation study

Chen, Ge; Lin, Hui

doi:10.1080/014311601750038839

Cited by 11 publications

(4 citation statements)

References 11 publications

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“…For comparisons between the buoy and satellite, a space domain of 0 to 150 km and a time domain of 0 to 1.5 h are typically acceptable under normal circumstances [1,3,32,33]. A relatively larger space window is chosen in the present study to avoid an insufficient number of data pairs.…”

Section: Buoy Observationsmentioning

confidence: 99%

Calibration Experiments of CFOSAT Wavelength in the Southern South China Sea by Artificial Neural Networks

Liu

et al. 2022

Remote Sensing

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The wave data measured by CFOSAT (China France Oceanography Satellite) have been validated mainly based on numerical model outputs and altimetry products on a global scale. It is still necessary to further calibrate the data for specific regions, e.g., the southern South China Sea. This study analyses the practicability of calibrating the dominant wavelength by using artificial neural networks and mean impact value analysis based on two sets of buoy data with a 2-year observation period and contemporaneous ERA5 reanalysis data. The artificial neural network modeling experiments are repeated 1000 times randomly by Monte Carlo methods to avoid sampling uncertainty. Both experimental results based on the random sampling method and chronological sampling method are performed. Independent buoy observations are used to validate the calibration model. The results show that although there are obvious differences between the CFOSAT wavelength data and the field observations, the parameters observed by the satellite itself can effectively calibrate the data. In addition to the wavelength, nadir significant wave height, nadir wind speed, and the distance between the calibration point and satellite observation point are the most important parameters for the calibration. Accurate data from other sources, such as ERA5, would be helpful to further improve the calibration results. The variable contributing the most to the calibration effect is the mean wave period, which virtually provides relatively accurate wavelength information for the calibration network. These results verify the possibility of synchronous self-calibration for the CFOSAT wavelength data and provide a reference for the further calibration of the satellite products in other regions.

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Section: Buoy Observationsmentioning

confidence: 99%

Calibration Experiments of CFOSAT Wavelength in the Southern South China Sea by Artificial Neural Networks

Liu

et al. 2022

Remote Sensing

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“…Some studies take 25 km as a spatial criterion [30]. Under normal circumstances, a space domain ranging from 0 to 150 km and a time domain varying from 0 to 1.5 h are also widely accepted for comparison between the buoy and satellite [31][32][33].…”

Section: Matching Methods Of Cfosat Data and In Situ Observationsmentioning

confidence: 99%

Evaluation of CFOSAT Wave Height Data with In Situ Observations in the South China Sea

Tang

et al. 2023

Remote Sensing

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The wave spectrometer operated by the China–France Oceanography Satellite (CFOSAT) can provide global ocean wave observation data. Although a lot of work on calibration and verification has been carried out in the open oceans dominated by swells, the quality of the data in the relatively enclosed sea area with complex terrain still lacks sufficient examination. The objective of this study is to assess the performance of the significant wave height data of the CFOSAT in the South China Sea (SCS), a unique sea area characterized by semi-enclosed basin and multi-reef terrain, and to recognize the environmental factors affecting the data quality. Compared against the long-term observations from five mooring or buoy sites, we find that the data is well performed in the relatively open and deep areas of the SCS, with an average correlation coefficient as high as 0.87, and a low average root-mean-square error of 0.47 m. However, the combined effects of complex topography, monsoons, and swell proportion variation will affect the performance of data. In the southern deep areas, the waves may be affected by a large number of dotted reefs, leading to wave deformations and energy dissipation in different seasons. In the northern nearshore areas, waves tend to be sheltered by the land or distorted by the shallow topography effects. These processes make it difficult for the swell to fully develop as in the open oceans. The low proportion of swell is a disadvantage for the CFOSAT to correctly observe the wave data and may lead to possible errors. Our results emphasize the importance of more verification when applying the CFOSAT data in certain local seas, and the necessity to adjust the algorithm of inverting wave spectra according to specific environmental factors.

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“…The OSCAT vector winds were collocated with the buoy wind data in both space and time. OSCAT wind vector cells within 25 km of buoy locations and within 30 minutes of buoy observations were collocated (Chen and Lin 2001). RAMA buoys measure winds at 4 m height, whereas TRITON buoys measure winds at 3.5 m height above the sea surface.…”

Section: Methodsmentioning

confidence: 99%

Comparison of Oceansat-2 scatterometer winds with buoy observations over the Indian Ocean and the Pacific Ocean

Sudha

Rao

2012

Remote Sensing Letters

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Technical note: Impacts of collocation window on the accuracy of altimeter/buoy wind-speed comparison-a simulation study

Cited by 11 publications

References 11 publications

Calibration Experiments of CFOSAT Wavelength in the Southern South China Sea by Artificial Neural Networks

Calibration Experiments of CFOSAT Wavelength in the Southern South China Sea by Artificial Neural Networks

Evaluation of CFOSAT Wave Height Data with In Situ Observations in the South China Sea

Comparison of Oceansat-2 scatterometer winds with buoy observations over the Indian Ocean and the Pacific Ocean

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