Interpolation of the surface geopotential (and hence, effectively,the orographic height) is affected by the changes to:
- the land sea-mask processing
- the default interpolation method
- the distance computation and selection of nearest points
HRES - O1280
The surface geopotential has been interpolated from the O1280 reduced Gaussian grid to regular lat-lon grids at different target resolutions using EMOSLIB and MIR.
- For the cases shown here, differences between MIR and EMOSLIB generally lie between+/-4500 m2/s2 (+/- 460 m)
- In general, more than 99.5% of points differ by less than +/-450 m2/s2 (+/-46 m)
- The largest differences occur close to the coasts and in areas of steep orography where the gradient of the surface geopotential field changes most rapidly
- Discounting differences due to land-sea mask processing, the differences between MIR and EMOSLIB generally lie between+/-1800 m2/s2 (+/-185 m) with differences for 99.5% of points being less than +/-160 m2/s2 (+/-16.5m)
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.
| Target resolution | Statistics of differences | Histogram of differences | Global | Europe |
|---|
| 0.1x0.1 | Maximum difference = 4200.527100
Minimum difference = -2743.472900
Mean absolute difference = 6.570708
Median absolute difference = 0.527100
Standard deviation = 34.616588
RMS of differences = 34.617696 Percentage of points with absolute difference < 10.00 = 90.423%
< 100.00 = 98.791%
< 500.00 = 99.920%
< 1000.00 = 99.987%
| -4201.500000 : -3437.590909 - 0 ( 0.000000%)
-3437.590909 : -2673.681818 - 2 ( 0.000031%)
-2673.681818 : -1909.772727 - 20 ( 0.000308%)
-1909.772727 : -1145.863636 - 225 ( 0.003470%)
-1145.863636 : -381.954545 - 3618 ( 0.055802%)
-381.954545 : 381.954545 - 6474512 ( 99.859831%)
381.954545 : 1145.863636 - 4889 ( 0.075406%)
1145.863636 : 1909.772727 - 277 ( 0.004272%)
1909.772727 : 2673.681818 - 38 ( 0.000586%)
2673.681818 : 3437.590909 - 15 ( 0.000231%)
3437.590909 : 4201.500000 - 4 ( 0.000062%) | | |
| 0.125x0.125 | Maximum difference = 3884.730225
Minimum difference = -2500.269775
Mean absolute difference = 6.497116
Median absolute difference = 0.730225
Standard deviation = 34.833189
RMS of differences = 34.834725 Percentage of points with absolute difference < 10.00 = 90.403%
< 100.00 = 98.775%
< 500.00 = 99.918%
< 1000.00 = 99.986% | -3885.500000 : -3179.045455 - 0 ( 0.000000%)
-3179.045455 : -2472.590909 - 1 ( 0.000024%)
-2472.590909 : -1766.136364 - 16 ( 0.000386%)
-1766.136364 : -1059.681818 - 178 ( 0.004289%)
-1059.681818 : -353.227273 - 2709 ( 0.065276%)
-353.227273 : 353.227273 - 4143208 ( 99.834413%)
353.227273 : 1059.681818 - 3697 ( 0.089083%)
1059.681818 : 1766.136364 - 219 ( 0.005277%)
1766.136364 : 2472.590909 - 33 ( 0.000795%)
2472.590909 : 3179.045455 - 15 ( 0.000361%)
3179.045455 : 3885.500000 - 4 ( 0.000096%) | | |
| 0.25x0.25 | Maximum difference = 2986.975342
Minimum difference = -2501.024658
Mean absolute difference = 6.421756
Median absolute difference = 0.024658
Standard deviation = 36.891598
RMS of differences = 36.893367 Percentage of points with absolute difference < 10.00 = 90.346%
< 100.00 = 98.733%
< 500.00 = 99.904%
< 1000.00 = 99.984% | -2987.500000 : -2444.318182 - 1 ( 0.000096%)
-2444.318182 : -1901.136364 - 4 ( 0.000385%)
-1901.136364 : -1357.954545 - 23 ( 0.002215%)
-1357.954545 : -814.772727 - 96 ( 0.009246%)
-814.772727 : -271.590909 - 1174 ( 0.113076%)
-271.590909 : 271.590909 - 1035253 ( 99.712302%)
271.590909 : 814.772727 - 1501 ( 0.144572%)
814.772727 : 1357.954545 - 150 ( 0.014448%)
1357.954545 : 1901.136364 - 23 ( 0.002215%)
1901.136364 : 2444.318182 - 9 ( 0.000867%)
2444.318182 : 2987.500000 - 6 ( 0.000578%) | | |
| 0.5x0.5 | Maximum difference = 2871.975342
Minimum difference = -4142.024658
Mean absolute difference = 7.259612
Median absolute difference = 0.024658
Standard deviation = 43.622669
RMS of differences = 43.624398 Percentage of points with absolute difference < 10.00 = 90.088%
< 100.00 = 98.533%
< 500.00 = 99.857%
< 1000.00 = 99.975% | -4143.500000 : -3390.136364 - 1 ( 0.000385%)
-3390.136364 : -2636.772727 - 0 ( 0.000000%)
-2636.772727 : -1883.409091 - 3 ( 0.001154%)
-1883.409091 : -1130.045455 - 20 ( 0.007695%)
-1130.045455 : -376.681818 - 251 ( 0.096568%)
-376.681818 : 376.681818 - 259309 ( 99.764928%)
376.681818 : 1130.045455 - 311 ( 0.119652%)
1130.045455 : 1883.409091 - 20 ( 0.007695%)
1883.409091 : 2636.772727 - 4 ( 0.001539%)
2636.772727 : 3390.136364 - 1 ( 0.000385%)
3390.136364 : 4143.500000 - 0 ( 0.000000%) | | |
| 1.0x1.0 | Maximum difference = 1291.310547
Minimum difference = -1724.689453
Mean absolute difference = 7.614173
Median absolute difference = 0.689453
Standard deviation = 41.118318
RMS of differences = 41.125978 Percentage of points with absolute difference < 10.00 = 90.020%
< 100.00 = 98.465%
< 500.00 = 99.848%
< 1000.00 = 99.988% | -1725.500000 : -1411.772727 - 1 ( 0.001535%)
-1411.772727 : -1098.045455 - 1 ( 0.001535%)
-1098.045455 : -784.318182 - 10 ( 0.015347%)
-784.318182 : -470.590909 - 28 ( 0.042971%)
-470.590909 : -156.863636 - 221 ( 0.339165%)
-156.863636 : 156.863636 - 64598 ( 99.137508%)
156.863636 : 470.590909 - 230 ( 0.352977%)
470.590909 : 784.318182 - 50 ( 0.076734%)
784.318182 : 1098.045455 - 16 ( 0.024555%)
1098.045455 : 1411.772727 - 5 ( 0.007673%)
1411.772727 : 1725.500000 - 0 ( 0.000000%) | | |
