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 resolutionParameterStatistics of differences (excluding 90N and 90S)Histogram of differences (excluding 90N and 90S)GlobalEurope
0.1x0.110u

Maximum difference = 2.655655
Minimum difference = -3.279892
Mean absolute difference = 0.010699
Median absolute difference = 0.002548
Standard deviation = 0.036172
RMS of differences = 0.036173

Percentage of points with absolute difference

        < 0.10 = 98.578%
        < 0.25 = 99.663%
        < 0.50 = 99.917%
        < 1.00 = 99.989%

-3.5 : -3.0 -          3 (  0.000046%)
-3.0 : -2.5 -          3 (  0.000046%)
-2.5 : -2.0 -         21 (  0.000324%)
-2.0 : -1.5 -         66 (  0.001018%)
-1.5 : -1.0 -        312 (  0.004812%)
-1.0 : -0.5 -       2603 (  0.040147%)
-0.5 : 0.0 -    3093830 ( 47.717780%)
  0.0 : 0.5 -    3384416 ( 52.199642%)
  0.5 : 1.0 -       2056 (  0.031711%)
  1.0 : 1.5 -        236 (  0.003640%)
  1.5 : 2.0 -         41 (  0.000632%)
  2.0 : 2.5 -         11 (  0.000170%)
  2.5 : 3.0 -          2 (  0.000031%)
  3.0 : 3.5 -          0 (  0.000000%)

10v

Maximum difference = 2.242844
Minimum difference = -3.879227
Mean absolute difference = 0.010432
Median absolute difference = 0.002609
Standard deviation = 0.035247
RMS of differences = 0.035247

Percentage of points with absolute difference

        < 0.10 = 98.638%
        < 0.25 = 99.673%
        < 0.50 = 99.915%
        < 1.00 = 99.991%

-4.0 : -3.5 -          2 (  0.000031%)
-3.5 : -3.0 -          0 (  0.000000%)
 -3.0 : -2.5 -          1 (  0.000015%)
 -2.5 : -2.0 -          3 (  0.000046%)
 -2.0 : -1.5 -         27 (  0.000416%)
 -1.5 : -1.0 -        269 (  0.004149%)
 -1.0 : -0.5 -       2393 (  0.036909%)
 -0.5 : 0.0 -    3468253 ( 53.492705%)
   0.0 : 0.5 -    3009813 ( 46.421942%)
   0.5 : 1.0 -       2569 (  0.039623%)
   1.0 : 1.5 -        244 (  0.003763%)
   1.5 : 2.0 -         24 (  0.000370%)
   2.0 : 2.5 -          2 (  0.000031%)
   2.5 : 3.0 -          0 (  0.000000%)
   3.0 : 3.5 -          0 (  0.000000%)
   3.5 : 4.0 -          0 (  0.000000%)

0.125x0.12510u

Maximum difference = 2.742874
Minimum difference = -3.841110
Mean absolute difference = 0.010641
Median absolute difference = 0.002640
Standard deviation = 0.035974
RMS of differences = 0.035975

Percentage of points with absolute difference

        < 0.10 = 98.599%
        < 0.25 = 99.663%
        < 0.50 = 99.918%
        < 1.00 = 99.990%

-4.0 : -3.5 -          1 (  0.000024%)
-3.5 : -3.0 -          3 (  0.000072%)
-3.0 : -2.5 -          7 (  0.000169%)
-2.5 : -2.0 -          8 (  0.000193%)
-2.0 : -1.5 -         31 (  0.000747%)
-1.5 : -1.0 -        198 (  0.004771%)
-1.0 : -0.5 -       1668 (  0.040192%)
-0.5 : 0.0 -    2236285 ( 53.885347%)
  0.0 : 0.5 -    1910412 ( 46.033137%)
  0.5 : 1.0 -       1280 (  0.030843%)
  1.0 : 1.5 -        153 (  0.003687%)
  1.5 : 2.0 -         24 (  0.000578%)
  2.0 : 2.5 -          8 (  0.000193%)
  2.5 : 3.0 -          2 (  0.000048%)
  3.0 : 3.5 -          0 (  0.000000%)
  3.5 : 4.0 -          0 (  0.000000%)

10v

Maximum difference = 2.211929
Minimum difference = -4.150375
Mean absolute difference = 0.010332
Median absolute difference = 0.002914
Standard deviation = 0.035219
RMS of differences = 0.035219

Percentage of points with absolute difference

        < 0.10 = 98.662%
        < 0.25 = 99.674%
        < 0.50 = 99.915%
        < 1.00 = 99.991%

-4.5 : -4.0 -          1 (  0.000024%)
-4.0 : -3.5 -          1 (  0.000024%)
-3.5 : -3.0 -          0 (  0.000000%)
-3.0 : -2.5 -          1 (  0.000024%)
-2.5 : -2.0 -          2 (  0.000048%)
-2.0 : -1.5 -         17 (  0.000410%)
-1.5 : -1.0 -        176 (  0.004241%)
-1.0 : -0.5 -       1507 (  0.036313%)
-0.5 : 0.0 -    1688708 ( 40.690975%)
  0.0 : 0.5 -    2457843 ( 59.223991%)
  0.5 : 1.0 -       1642 (  0.039566%)
  1.0 : 1.5 -        168 (  0.004048%)
  1.5 : 2.0 -         12 (  0.000289%)
  2.0 : 2.5 -          2 (  0.000048%)
  2.5 : 3.0 -          0 (  0.000000%)
  3.0 : 3.5 -          0 (  0.000000%)
  3.5 : 4.0 -          0 (  0.000000%)
  4.0 : 4.5 -          0 (  0.000000%)

0.25x0.2510u

Maximum difference = 2.006119
Minimum difference = -3.840561
Mean absolute difference = 0.010868
Median absolute difference = 0.002670
Standard deviation = 0.038290
RMS of differences = 0.038291

Percentage of points with absolute difference

        < 0.10 = 98.533%
        < 0.25 = 99.614%
        < 0.50 = 99.899%
        < 1.00 = 99.986%

-4.0 : -3.5 -          1 (  0.000096%)
-3.5 : -3.0 -          0 (  0.000000%)
-3.0 : -2.5 -          2 (  0.000193%)
-2.5 : -2.0 -          2 (  0.000193%)
-2.0 : -1.5 -          9 (  0.000867%)
-1.5 : -1.0 -         79 (  0.007609%)
-1.0 : -0.5 -        527 (  0.050759%)
-0.5 : 0.0 -     465868 ( 44.870935%)
  0.0 : 0.5 -     571323 ( 55.028028%)
  0.5 : 1.0 -        379 (  0.036504%)
  1.0 : 1.5 -         41 (  0.003949%)
  1.5 : 2.0 -          8 (  0.000771%)
  2.0 : 2.5 -          1 (  0.000096%)
  2.5 : 3.0 -          0 (  0.000000%)
  3.0 : 3.5 -          0 (  0.000000%)
  3.5 : 4.0 -          0 (  0.000000%)

10v

Maximum difference = 1.868179
Minimum difference = -2.262680
Mean absolute difference = 0.010483
Median absolute difference = 0.002914
Standard deviation = 0.036397
RMS of differences = 0.036397

Percentage of points with absolute difference

        < 0.10 = 98.594%
        < 0.25 = 99.633%
        < 0.50 = 99.907%
        < 1.00 = 99.991%

-2.5 : -2.0 -          2 (  0.000193%)
-2.0 : -1.5 -          6 (  0.000578%)
-1.5 : -1.0 -         41 (  0.003949%)
-1.0 : -0.5 -        398 (  0.038334%)
-0.5 : 0.0 -     415556 ( 40.025042%)
  0.0 : 0.5 -     621719 ( 59.882012%)
  0.5 : 1.0 -        476 (  0.045847%)
  1.0 : 1.5 -         37 (  0.003564%)
  1.5 : 2.0 -          5 (  0.000482%)
  2.0 : 2.5 -          0 (  0.000000%)

0.5x0.510u

Maximum difference = 2.465591
Minimum difference = -2.399643
Mean absolute difference = 0.011799
Median absolute difference = 0.002701
Standard deviation = 0.045343
RMS of differences = 0.045343

Percentage of points with absolute difference

        < 0.10 = 98.207%
        < 0.25 = 99.449%
        < 0.50 = 99.845%
        < 1.00 = 99.978%

-2.5 : -2.0 -          3 (  0.001154%)
-2.0 : -1.5 -          5 (  0.001924%)
-1.5 : -1.0 -         29 (  0.011157%)
-1.0 : -0.5 -        180 (  0.069252%)
-0.5 : 0.0 -     144921 ( 55.756002%)
  0.0 : 0.5 -     114595 ( 44.088566%)
  0.5 : 1.0 -        166 (  0.063866%)
  1.0 : 1.5 -         17 (  0.006540%)
  1.5 : 2.0 -          2 (  0.000769%)
  2.0 : 2.5 -          2 (  0.000769%)


10v

Maximum difference = 1.750687
Minimum difference = -1.841110
Mean absolute difference = 0.011405
Median absolute difference = 0.002640
Standard deviation = 0.042246
RMS of differences = 0.042246

Percentage of points with absolute difference

        < 0.10 = 98.289%
        < 0.25 = 99.493%
        < 0.50 = 99.861%
        < 1.00 = 99.982%

-2.0 : -1.5 -          2 (  0.000769%)
-1.5 : -1.0 -         20 (  0.007695%)
-1.0 : -0.5 -        148 (  0.056941%)
-0.5 : 0.0 -     141343 ( 54.379424%)
  0.0 : 0.5 -     118216 ( 45.481687%)
  0.5 : 1.0 -        166 (  0.063866%)
  1.0 : 1.5 -         24 (  0.009234%)
  1.5 : 2.0 -          1 (  0.000385%)


1.0x1.010u

Maximum difference = 2.465393
Minimum difference = -2.399841
Mean absolute difference = 0.011716
Median absolute difference = 0.002380
Standard deviation = 0.047399
RMS of differences = 0.047399

 Percentage of points with absolute difference

        < 0.10 = 98.171%
        < 0.25 = 99.429%
        < 0.50 = 99.840%
        < 1.00 = 99.975%

-2.5 : -2.0 -          2 (  0.003069%)
-2.0 : -1.5 -          2 (  0.003069%)
-1.5 : -1.0 -          7 (  0.010743%)
-1.0 : -0.5 -         46 (  0.070595%)
-0.5 : 0.0 -      33182 ( 50.923880%)
  0.0 : 0.5 -      31874 ( 48.916513%)
  0.5 : 1.0 -         42 (  0.064457%
  1.0 : 1.5 -          3 (  0.004604%)
  1.5 : 2.0 -          1 (  0.001535%)
  2.0 : 2.5 -          1 (  0.001535%)


10v

Maximum difference = 1.342804
Minimum difference = -1.771454
Mean absolute difference = 0.011245
Median absolute difference = 0.001984
Standard deviation = 0.042607
RMS of differences = 0.042607

Percentage of points with absolute difference

        < 0.10 = 98.194%
        < 0.25 = 99.471%
        < 0.50 = 99.859%
        < 1.00 = 99.980%

-2.0 : -1.5 -          1 (  0.001535%)
-1.5 : -1.0 -          7 (  0.010743%)
-1.0 : -0.5 -         36 (  0.055249%)
-0.5 : 0.0 -      24291 ( 37.279006%)
  0.0 : 0.5 -      40777 ( 62.579804%)
  0.5 : 1.0 -         43 (  0.065991%)
  1.0 : 1.5 -          5 (  0.007673%)
  1.5 : 2.0 -          0 (  0.000000%)