diff --git a/python/extpar_aot_to_buffer.py b/python/extpar_aot_to_buffer.py
index e141b413..6edc9bf3 100755
--- a/python/extpar_aot_to_buffer.py
+++ b/python/extpar_aot_to_buffer.py
@@ -123,14 +123,21 @@
 logging.info('============= CDO: remap to target grid ========')
 logging.info('')
 
+# Compute longitude and latitude resolution of the raw dataset
+raw_data_aot_nc = nc.Dataset(raw_data_aot, "r")
+lon = raw_data_aot_nc.variables['lon']
+lat = raw_data_aot_nc.variables['lat']
+dlon = lon[1] - lon[0]
+dlat = lat[1] - lat[0]
+
 # calculate weights
 utils.launch_shell('cdo', '-f', 'nc4', lock, '-P', omp, f'genbil,{grid}',
-                   raw_data_aot, weights)
+                   tg.cdo_sellonlat(dlon, dlat), raw_data_aot, weights)
 
 # regrid aot
 utils.launch_shell('cdo', '-f', 'nc4', lock, '-P', omp,
                    f'settaxis,1111-01-01,0,1mo', f'-remap,{grid},{weights}',
-                   raw_data_aot, aot_cdo)
+                   tg.cdo_sellonlat(dlon, dlat), raw_data_aot, aot_cdo)
 
 #--------------------------------------------------------------------------
 #--------------------------------------------------------------------------
diff --git a/python/lib/grid_def.py b/python/lib/grid_def.py
index 2eb48256..a1c9aec4 100644
--- a/python/lib/grid_def.py
+++ b/python/lib/grid_def.py
@@ -213,7 +213,7 @@ def phirot2phi(self, phirot, rlarot, polphi, pollam):
 
         return phi
 
-    def cdo_sellonlat(self):
+    def cdo_sellonlat(self, dlon=1.0, dlat=1.0):
         '''
         create the string for the cdo option "-sellonlatbox"
 
@@ -223,11 +223,11 @@ def cdo_sellonlat(self):
         '''
 
         extent = {}
-        extent['maxlon'] = min(math.ceil(np.amax(self.lons) + 1), 180.0)
-        extent['minlon'] = max(math.floor(np.amin(self.lons) - 1), -180.0)
+        extent['maxlon'] = min(math.ceil(np.amax(self.lons) + dlon), 180.0)
+        extent['minlon'] = max(math.floor(np.amin(self.lons) - dlon), -180.0)
 
-        extent['maxlat'] = min(math.ceil(np.amax(self.lats) + 1), 90.0)
-        extent['minlat'] = max(math.floor(np.amin(self.lats) - 1), -90.0)
+        extent['maxlat'] = min(math.ceil(np.amax(self.lats) + dlat), 90.0)
+        extent['minlat'] = max(math.floor(np.amin(self.lats) - dlat), -90.0)
 
         cdo_selbox = ('-sellonlatbox,'
                       f"{extent['minlon']},"
@@ -263,7 +263,7 @@ def __init__(self, gridfile):
         self.vlons = np.rad2deg(self.grid.variables["vlon"][:])
         self.vlats = np.rad2deg(self.grid.variables["vlat"][:])
 
-    def cdo_sellonlat(self):
+    def cdo_sellonlat(self, dlon=1.0, dlat=1.0):
         '''
         create the string for the cdo option "-sellonlatbox"
 
@@ -273,11 +273,11 @@ def cdo_sellonlat(self):
         '''
 
         extent = {}
-        extent['maxlon'] = min(math.ceil(np.amax(self.lons) + 1), 180.0)
-        extent['minlon'] = max(math.floor(np.amin(self.lons) - 1), -180.0)
+        extent['maxlon'] = min(math.ceil(np.amax(self.lons) + dlon), 180.0)
+        extent['minlon'] = max(math.floor(np.amin(self.lons) - dlon), -180.0)
 
-        extent['maxlat'] = min(math.ceil(np.amax(self.lats) + 1), 90.0)
-        extent['minlat'] = max(math.floor(np.amin(self.lats) - 1), -90.0)
+        extent['maxlat'] = min(math.ceil(np.amax(self.lats) + dlat), 90.0)
+        extent['minlat'] = max(math.floor(np.amin(self.lats) - dlat), -90.0)
 
         cdo_selbox = ('-sellonlatbox,'
                       f"{extent['minlon']},"