Assessment of the offshore wind resource in Japan with the ASCAT microwave scatterometer

Takeyama, Yuko; Ohsawa, Teruo; Shimada, Shinichi; Kozai, Katsutoshi; Kawaguchi, Koji; Kogaki, Tetsuya

doi:10.1080/01431161.2018.1524588

Cited by 9 publications

(10 citation statements)

References 16 publications

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“…In this study, all types of minor flag were ignored because removing wind related to specific atmospheric and oceanographic conditions could result in an inaccurate frequency distribution of wind speed and direction. Instead of using land flags, which were considered minor flags, only the ASCAT wind field for open ocean—that is, where the distance from the coastline is more than 25 km—was used, because our previous study showed that the interference from the land does not appear at this distance even if these minor flags were ignored 15 …”

Section: Methodsmentioning

confidence: 99%

“…For the accuracy of the wind speeds simulated by the WRF, annual wind biases of 0.01 to 0.62 m/s at 100 m above MSL and −0.35 to −0.10 m/s at 90 m above MSL have been reported for the South Baltic Sea, 13 and annual wind biases of less than 3.2% have been reported at around 100 m above MSL in the North Sea 14 . In a previous study that compared accuracies of surface wind speeds obtained from ASCAT and the WRF model over the Pacific Ocean near Japan, ASCAT was shown to estimate the offshore wind speed more accurately than the WRF model 15 . However, it has also been shown that the WRF model can be used to estimate offshore wind speed at a much higher spatial resolution than ASCAT, with a finest resolution of 12.5 km.…”

Section: Introductionmentioning

confidence: 97%

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A comparison between Advanced Scatterometer and Weather Research and Forecasting wind speeds for the Japanese offshore wind resource map

Takeyama

Ohsawa

Tanemoto³

et al. 2020

Wind Energy

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This paper investigates the validity of the method used in the Japanese offshore wind map (NeoWins) to seamlessly connecting satellite-derived wind speed for open oceans to mesoscale model-simulated wind speed for coastal waters. In the Neo-Wins, the former was obtained from the satellite-borne Advanced Scatterometer (ASCAT), and the latter was obtained from numerical simulations using the Weather Research and Forecasting (WRF) model. In this study, the consistency of the ASCAT and WRF 10-m height wind speeds is examined in their overwrapping areas. The comparison between ASCAT and WRF model reveals that their differences in annual mean wind speed are mostly within ±5% and that the ASCAT annual mean wind speed is, as a whole, slightly higher than the WRF annual mean wind speed. The results indicate that there are no large wind speed gaps between WRF and ASCAT in most parts of the Japanese offshore areas. It is moreover found that the discrepancies between the two wind speeds are due to two factors: one is the existence of winter sea ice in the ASCAT observation in the Sea of Okhotsk in ASCAT observation and the other is that the accuracy of the WRF wind speed depends on atmospheric stability. K E Y W O R D SASCAT, NeoWins, offshore wind, WRF | INTRODUCTIONOffshore wind resource maps have been developed worldwide using various methods, including satellite observations, numerical simulations, and the interpolation/extrapolation of in situ observations. A recent offshore wind resource map for Japan developed by the New Energy and Industrial Technology Development Organization (NEDO), called "offshore wind information system" (NeoWins), 1 employed both a satellite-borne microwave scatterometer and a mesoscale model-simulated wind speeds with spatial resolutions of approximately 10 km and 500 m, respectively; the two types of wind field were connected horizontally at around 30 km from the coastline.Data from satellite-borne microwave scatterometers can be used to construct reliable offshore wind resource maps, especially for open oceans. For example, wind fields obtained from the Advanced Scatterometer (ASCAT) 2 -a microwave scatterometer carried onboard to European Space Agency's MetOp satellites-have been used to develop an offshore wind atlas project. 3 A microwave scatterometer measures backscattering strengths from the earth's surface. An empirical relationship has been derived between the backscattering strength and the wind speed and

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

A comparison between Advanced Scatterometer and Weather Research and Forecasting wind speeds for the Japanese offshore wind resource map

Takeyama

Ohsawa

Tanemoto³

et al. 2020

Wind Energy

Self Cite

View full text Add to dashboard Cite

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“…The model takes into account two steady-state operations of this system: excitation (both transistors on) and generation (both transistors off). In the excited state, the phase voltage describes the relationship (10), and in the generation state (11).…”

Section: Mathematical Model Of the Generatormentioning

confidence: 99%

“…Development in a given location is determined mainly by wind conditions [1][2][3][4][5][6][7][8][9][10]. Most wind farms are built in coastal areas and on continental shelves [10][11][12][13][14][15][16][17][18]. Inland, wind conditions, being determined by various topographical and other factors, vary greatly [1,11,[19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

“…Most wind farms are built in coastal areas and on continental shelves [10][11][12][13][14][15][16][17][18]. Inland, wind conditions, being determined by various topographical and other factors, vary greatly [1,11,[19][20][21][22]. Therefore, the construction of wind farms in such locations should be preceded by studies of annual wind distribution in these locations.…”

Section: Introductionmentioning

confidence: 99%

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Optimization of a Small Wind Power Plant for Annual Wind Speed Distribution

et al. 2021

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This article presents a method to adjust the elements of a small wind power plant to the wind speed characterized by the highest annual level of energy. Tests were carried out on the basis of annual wind distributions at three locations. The standard range of wind speeds was reduced to that resulting from the annual wind speed distributions in these locations. The construction of the generators and the method of their excitation were adapted to the characteristics of the turbines. The results obtained for the designed power plants were compared with those obtained for a power plant with a commercial turbine adapted to a wind speed of 10 mps. The generator structure and control method were optimized using a genetic algorithm in the MATLAB program (Mathworks, Natick, MA, USA); magnetostatic calculations were carried out using the FEMM program; the simulations were conducted using a proprietary simulation program. The simulation results were verified by measurement for a switched reluctance machine of the same voltage, power, and design. Finally, the yields of the designed generators in various locations were determined.

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Validation of near‐shore wind measurements using a dual scanning light detection and ranging system

et al. 2022

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This paper reports results from a 2-month validation campaign of near-shore wind measurements taken by a dual scanning light detection and ranging (LiDAR) system at a coastal site in Japan. A meteorological mast and a vertical profiling LiDAR device were deployed at an offshore research station approximately 1.5 km from the coast.Offshore winds at heights of 66, 120, and 180 m above sea level were observed by the scanning LiDAR system. Comparisons with a sonic anemometer found that the radial velocities had a coefficient of determination of more than 0.99 without unreasonable bias. The accuracy of 10-min mean wind speeds and directions was then evaluated. The 10-min values from the dual scanning LiDAR system were accurate enough to satisfy the acceptance criteria used for floating LiDAR systems. In addition, the vertical velocity and direction profiles from the dual scanning LiDAR system were compared with those from a vertical profiling LiDAR device. The performance of turbulence intensity (TI) measurements was also evaluated. Although the TIs from the dual scanning LiDAR system were slightly lower than those from the sonic anemometer, they were equivalent to those from the cup anemometers. This investigation concluded that the near-shore wind measurements using the dual scanning LiDAR system are beneficial for reducing near-shore wind measurement costs, because the system can measure not only 10-min wind speed and direction, but also parameters associated with assessing site-specific conditions without installing offshore meteorological masts.

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Assessment of the offshore wind resource in Japan with the ASCAT microwave scatterometer

Cited by 9 publications

References 16 publications

A comparison between Advanced Scatterometer and Weather Research and Forecasting wind speeds for the Japanese offshore wind resource map

A comparison between Advanced Scatterometer and Weather Research and Forecasting wind speeds for the Japanese offshore wind resource map

Optimization of a Small Wind Power Plant for Annual Wind Speed Distribution

Validation of near‐shore wind measurements using a dual scanning light detection and ranging system

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