* scatter_multi.ncl: uncount over land

Signed-off-by: Yakkala Yagnesh Raghava <hi@yagnesh.org>
* mask_land.ncl: new

Signed-off-by: Yakkala Yagnesh Raghava <hi@yagnesh.org>
* scatter_multi.ncl: use variables

Signed-off-by: Yakkala Yagnesh Raghava <hi@yagnesh.org>