# Differences for total precipitation

Interpolation of total precipitation is affected by the changes to:

• the default interpolation method
• the distance computation and selection of nearest points
• the change to the precipitation thresholds

## HRES - O1280

Total precipitation for a 24 hour period  has been interpolated from the O1280 octahedral 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 are generally less than +/- 25mm
• In general, more than 99.5% of points differ by less than 0.5mm
• The largest differences occur close to the coasts and in areas where the gradient of the field 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.

Target resolutionStatistics of differencesHistogram of differencesGlobalEurope
0.1x0.1

Maximum difference = 19.104004
Minimum difference = -22.705078
Mean absolute difference = 0.020782
Median absolute difference = 0.000000
Standard deviation = 0.101433
RMS of differences = 0.101460

Percentage of points with absolute difference

< 0.10 = 96.346%
< 0.50 = 99.548%
< 1.00 = 99.861%

-25.0 :-20.0 -          1 (  0.000015%)
-20.0 :-15.0 -          2 (  0.000031%)
-15.0 :-10.0 -         17 (  0.000262%)
-10.0 :-5.0 -        116 (  0.001789%)
-5.0 :0.0 -    1786184 ( 27.549263%)
0.0 :5.0 -    4697178 ( 72.447066%)
5.0 :10.0 -         94 (  0.001450%)
10.0 :15.0 -          7 (  0.000108%)
15.0 :20.0 -          1 (  0.000015%)
20.0 :25.0 -          0 (  0.000000%)

0.125x0.125

Maximum difference = 10.871887
Minimum difference = -22.705078
Mean absolute difference = 0.020879
Median absolute difference = 0.000000
Standard deviation = 0.100942
RMS of differences = 0.100969

Percentage of points with absolute difference

< 0.10 = 96.319%
< 0.50 = 99.542%
< 1.00 = 99.854%

-25.0 :-20.0 -          1 (  0.000024%)
-20.0 :-15.0 -          2 (  0.000048%)
-15.0 :-10.0 -          6 (  0.000145%)
-10.0 :-5.0 -         73 (  0.001759%)
-5.0 :0.0 -    1141413 ( 27.503398%)
0.0 :5.0 -    3008520 ( 72.493060%)
5.0 :10.0 -         62 (  0.001494%)
10.0 :15.0 -          3 (  0.000072%)
15.0 :20.0 -          0 (  0.000000%)
20.0 :25.0 -          0 (  0.000000%)

0.25x0.25

Maximum difference = 10.833740
Minimum difference = -22.705078
Mean absolute difference = 0.021054
Median absolute difference = 0.000000
Standard deviation = 0.105902
RMS of differences = 0.105929

Percentage of points with absolute difference

< 0.10 = 96.313%
< 0.50 = 99.539%
< 1.00 = 99.846%

-25.0 :-20.0 -          1 (  0.000096%)
-20.0 :-15.0 -          0 (  0.000000%)
-15.0 :-10.0 -          3 (  0.000289%)
-10.0 :-5.0 -         21 (  0.002023%)
-5.0 :0.0 -     283568 ( 27.312375%)
0.0 :5.0 -     754629 ( 72.683484%)
5.0 :10.0 -         16 (  0.001541%)
10.0 :15.0 -          2 (  0.000193%)
15.0 :20.0 -          0 (  0.000000%)
20.0 :25.0 -          0 (  0.000000%)

0.5x0.5

Maximum difference = 11.169434
Minimum difference = -11.848450
Mean absolute difference = 0.021755
Median absolute difference = 0.000000
Standard deviation = 0.114793
RMS of differences = 0.114817

Percentage of points with absolute difference

< 0.10 = 96.267%
< 0.50 = 99.493%
< 1.00 = 99.818%

-15.0 :-10.0 -          1 (  0.000385%
-10.0 :-5.0 -          6 (  0.002308%)
-5.0 :0.0 -      70372 ( 27.074484%)
0.0 :5.0 -     189536 ( 72.920899%)
5.0 :10.0 -          4 (  0.001539%)
10.0 :15.0 -          1 (  0.000385%)

1.0x1.0

Maximum difference = 8.422852
Minimum difference = -11.848450
Mean absolute difference = 0.021210
Median absolute difference = 0.000000
Standard deviation = 0.122580
RMS of differences = 0.122593

Percentage of points with absolute difference

< 0.10 = 96.466%
< 0.50 = 99.520%
< 1.00 = 99.831%

-15.0 :-10.0 -          1 (  0.001535%)
-10.0 :-5.0 -          2 (  0.003069%)
-5.0 :0.0 -      17289 ( 26.533149%)
0.0 :5.0 -      47867 ( 73.460712%)
5.0 :10.0 -          1 (  0.001535%)
10.0 :15.0 -          0 (  0.000000%)