Interpolation of the land-sea mask shows differences due to:

• MIR returns fractional values between 0 and 1 whereas EMOSLIB returns only 0 (sea) or 1 (land)
• the default interpolation method
• the distance computation and selection of nearest points

As a consequence, a small number of points change nature from land to sea or vice versa.

# HRES O1280

The land-sea mask has been interpolated from the O1280 octahedral reduced Gaussian source grid to regular lat-lon target grids at different target resolutions using EMOSLIB and MIR.

• Fewer than 0.05% of grid points are different
• The differences all occur at the coast or close to large lakes and rivers

The plots show the location of the points that differ:

• the blue dots indicate grid points where the LSM field produced with MIR has a land point while that produced with EMOSLIB has sea point
• the red dots indicate points where the LSM field produced with EMOSLIB has a land point while that produced with MIR has sea point

TargetStatistics of differencesGlobalEurope
0.1x0.1

Number of points different =  2302
Sea (EMOSLIB) to Land (MIR) = 1076
Land (EMOSLIB) to Sea (MIR) = 1226

Percentage of points unchanged = 99.964%

0.125x0.125

Number of points different = 1409
Sea (EMOSLIB) to Land (MIR) = 635
Land (EMOSLIB) to Sea (MIR) = 774

Percentage of points unchanged = 99.966%

0.25x0.25

Number of points different = 340
Sea (EMOSLIB) to Land (MIR) = 147
Land (EMOSLIB) to Sea (MIR) = 193

Percentage of points unchanged = 99.967%

0.5x0.5

Number of points different = 69
Sea (EMOSLIB) to Land (MIR) = 29
Land (EMOSLIB) to Sea (MIR) = 40

Percentage of points unchanged = 99.973%

1.0x1.0

Number of points different = 14
Sea (EMOSLIB) to Land (MIR) = 7
Land (EMOSLIB) to Sea (MIR) = 7

Percentage of points unchanged = 99.979%