Add make_land for GLOBAL_025

Compute/make_land.py

 """Obtain land masks."""
+from os import path
 
 import numpy as np
 import xarray as xr
@@ -31,6 +32,7 @@ def write_land(ds, land, filename, grid):
     if 'time' in ds.land.dims:
         ds = ds.isel(time=0)
     ds = enlarge(ds)
+    ds = ds.reset_coords(drop=True)
     ds.to_netcdf(filename, encoding={'land': {'zlib': True}})
     return ds
 
@@ -38,6 +40,11 @@ def write_land(ds, land, filename, grid):
 def enlarge(ds):
     n_km = 20
     n = int(n_km / abs(ds.lat.diff('lat').mean().values * 111))
+
+    if n < 1:
+        ds['land_large'] = ds['land']
+        return ds
+
     N = 2*n+1
     pos = np.indices([N, N]) - n
     rad = np.linalg.norm(pos, 2, axis=0)
@@ -60,6 +67,14 @@ def enlarge(ds):
 
 
 def make_land(args):
+    # 1/4°
+    grid = 'GLOBAL_025'
+    filename = get_filename(grid, args)
+    ds = xr.open_dataset(path.join(lib.root_data, args['region'],
+                                   'zones', 'ERA5_land_area_fraction.nc'))
+    land = ds.sftlf > 0.1
+    write_land(ds, land, filename, grid)
+
     # 1km
     grid = '1km'
     filename = get_filename(grid, args)