Table 1.
Detailed information of the observation datasets.
Fig 1.
Location on the map of each wind observation station.
The color scale represents the Perkins Skill Score for each location. The wind frequency distribution of the stations marked with a red square symbol is shown in Fig 5.
Table 2.
General technical specification for GW154/6700.
Fig 2.
Wind speed box plots at observation stations (red) and ERA5 cells (green) at heights of 10m and 100m, respectively.
The boundary of the boxes represents the positions of the 25th and 75th percentiles, and the middle line represents the 50th percentile. The upper whisker is a maximum value, while the lower whisker is a minimum value, and cycle indicates the outliers exceeding three times the standard deviation.
Table 3.
Wind speed statistical evaluation between observation stations and ERA5 data at heights of 10m.
Table 4.
Wind speed statistical evaluation between observation stations and ERA5 data at heights of 100m.
Fig 3.
Comparison hourly means of wind speeds from 19 wind observation stations with ERA5 reanalysis wind data in the China’s offshore water.
The diagonal line indicates a perfect fit.
Fig 4.
The normalized Taylor plots of wind observations and ERA5 reanalysis compared the hourly (red dots), 6-hour (green dots), and 24-hour (pink dots) data of each station during the measurement period.
The Pearson correlation coefficient between ERA5 and observation is given by the azimuthal position, and the standard deviation ratio between the ERA5 and the observed values is represented by the radial distance from the origin. The reanalyzed CRMSE is represented as the radial distance from the position of the observation (green semicircle). In this case, when the point is closer to the observation σ = 1, R = 1, and CRMSE = 0, reanalysis will represent better observed data. Stations marked with squares and symbols represent the stations with the highest scores, while stations marked with crosses and triangles represent the stations with the lowest scores.
Fig 5.
Frequency distribution of the hourly ERA5 reanalysis vs observations illustrating the best score (a: W02 station and b: W11 station) and the poorest score (c: W18 station and b: W19 station).
The location of each station can be seen marked with station ID in Fig 1.
Fig 6.
Comparison of wind roses between ERA5 reanalysis and in-situ measured data. a: W03 station, b: W08 station, c: W13 station and d: W19 station.
The location of station is marked in Fig 1 with station ID.
Fig 7.
Scatter plot matrix of wind parameters for hourly wind speed observations data at each location: score, CV (coefficient of variation), frequency of values above the Cut-out (25 m/s) and under the Cut-in (3 m/s) rates.
Upper panels show the Pearson’s correlation for each variable pairs and lower panels show scatter plots. Grayscale indicates ranges of score from lower to higher scores.