MARS/Dissemination

Specifies how to apply land-sea mask processing.

lsm=<value>

MIR, the interpolation package used in MARS and Dissemination, does not apply land-sea mask processing to any parameter by default. However, even thought not recommended, users can request land-sea mask processing for generation of points in the target grid. The idea is to use the land-sea mask of both source and target grids to modify the effect of the input points on the target value being generated for those input points having a different land-sea nature to that of the target grid point. For example, if a sea point is being generated in the target grid from four neighbouring points in the source grid, three of which are sea points (i.e., with land-sea mask values less than 0.5) and one of which is a land point (with land-sea mask value greater than 0.5), then the weight of the input grid land point in the interpolation will be reduced so that it contributes less to the final target value.

The land-sea mask applied in MIR is based on a 1 km resolution field. The weight adjustment factor applied is 0.2. MIR does not apply land-sea mask processing when using the nearest neighbour method.

Examples: