Interpolation of the surface winds at 10m is affected by the changes to:
- the land sea-mask processing
- the default interpolation method
- the distance computation and selection of nearest points
- the handling of the interpolation at the polar latitudes
HRES - O1280
The 10u and 10v components of wind have been interpolated from the O1280 octahedral reduced Gaussian target grid to regular lat-lon grids at different target resolutions using EMOSLIB and MIR.
- Large differences are seen for the values at the polar latitude line (90N and 90S).
- Neglecting the differences at the polar latitudes, differences between MIR and EMOSLIB generally lie between +/- 4.0m/s
- In general, more than 98.5% points differ by less than +/- 0.1m/s
- The largest differences occur close to the coasts and in areas where the gradient of the fields changes most rapidly
The plots show the differences with the contours chosen on a logarithmic scale to enhance the smaller differences. Differences smaller than 0.1% of the field range are not shown. Grid points where the absolute difference is greater than 25% of the maximum absolute difference are indicated with red (EMOSLIB greater than MIR) and blue (EMOSLIB less than MIR) filled circles. The line of slightly larger differences visible in all plots to the north west of the United Kingdom and Ireland is due to a stationary front with a strong south-westerly flow to the south east.
Target resolution | Parameter | Statistics of differences (excluding 90N and 90S) | Histogram of differences (excluding 90N and 90S) | Global | Europe |
---|---|---|---|---|---|
0.1x0.1 | 10u | Maximum difference = 2.655655 Percentage of points with absolute difference < 0.10 = 98.578% | -3.5 : -3.0 - 3 ( 0.000046%) | ||
10v | Maximum difference = 2.242844 Percentage of points with absolute difference < 0.10 = 98.638% | -4.0 : -3.5 - 2 ( 0.000031%) | |||
0.125x0.125 | 10u | Maximum difference = 2.742874 Percentage of points with absolute difference < 0.10 = 98.599% | -4.0 : -3.5 - 1 ( 0.000024%) | ||
10v | Maximum difference = 2.211929 Percentage of points with absolute difference < 0.10 = 98.662% | -4.5 : -4.0 - 1 ( 0.000024%) | |||
0.25x0.25 | 10u | Maximum difference = 2.006119 Percentage of points with absolute difference < 0.10 = 98.533% | -4.0 : -3.5 - 1 ( 0.000096%) | ||
10v | Maximum difference = 1.868179 Percentage of points with absolute difference < 0.10 = 98.594% | -2.5 : -2.0 - 2 ( 0.000193%) | |||
0.5x0.5 | 10u | Maximum difference = 2.465591 Percentage of points with absolute difference < 0.10 = 98.207% | -2.5 : -2.0 - 3 ( 0.001154%) | ||
10v | Maximum difference = 1.750687 Percentage of points with absolute difference < 0.10 = 98.289% | -2.0 : -1.5 - 2 ( 0.000769%) | |||
1.0x1.0 | 10u | Maximum difference = 2.465393 Percentage of points with absolute difference < 0.10 = 98.171% | -2.5 : -2.0 - 2 ( 0.003069%) | ||
10v | Maximum difference = 1.342804 Percentage of points with absolute difference < 0.10 = 98.194% | -2.0 : -1.5 - 1 ( 0.001535%) |