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

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

Percentage of points unchanged = 99.964%


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

Percentage of points unchanged = 99.966%


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

Percentage of points unchanged = 99.967%


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

Percentage of points unchanged = 99.973%


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

Percentage of points unchanged = 99.979%

  • No labels