diff --git a/src/tbxsectors.py b/src/tbxsectors.py
index f78487ad92ff8e640562623ae59857265f499726..52fc45c52cd684aa51647f7de36618d146485759 100644
--- a/src/tbxsectors.py
+++ b/src/tbxsectors.py
@@ -5,7 +5,6 @@ import matplotlib.path as mpath
 import cartopy.crs as ccrs
 import cartopy.feature as cfeat
 from pathlib import Path
-from pyproj import CRS, Transformer
 
 def define_sectors(ref="RH"):
     """
@@ -86,8 +85,9 @@ def interp_mask2grid(target_grid=None,
     Inputs: - target_grid: the target grid on which to interpolate the NSIDC mask. 
                            It can be a xr.Dataset containing lat and lon variables defining the grid,
                            or a string mentioning the grid: 
-                               if weights='ORCA1_nh', use the weights for Northern Hemisphere ORCA1 config; 
-                               if 'ORCA025_nh', use the weights for NorthH for ORCA025
+                            - if 'ORCA1_nh', use the mask for Northern Hemisphere ORCA1 config; 
+                            - if 'ORCA025_nh', use the mask for Northern Hemisphere for ORCA025;
+                            - any other string: a user-calculated mask already interpolated on the target grid.
                            #TODO: need to add full ORCA1 and ORCA025, as well as ORCA12 and ORCA12_nh
             -maskFile: path and name of file containing the NSIDC mask.
 
@@ -101,41 +101,22 @@ def interp_mask2grid(target_grid=None,
             ds_mask_interp = xr.open_dataset(Path.cwd().joinpath('../data/NSIDCRegionsMask_ORCA025_nh.nc'))
         else:
             ds_mask_interp = xr.open_dataset(target_grid)
-    else:
+    else: # If the target grid is a dataset or dataarray, interpolate the mask onto it.
         # First of all, load the mask
         ds_mask = xr.open_dataset(maskFile)
-        # ------------- If no lat-lon in the ds_mask, calculate and add them -------------
-        if 'lat' not in list(ds_mask.coords):
-            # Convert from projected coordinates to lat-lon coordinates 
-            # A first issue is that the mask is provided in North Polar Stereographic projection
-            # Extract the x and y (projection) coordinates and grid them (from 1D to 2D)
-            x_mask, y_mask = np.meshgrid(ds_mask.x, ds_mask.y)
-            # Define the projection and geographic systems according to CRS conventions.
-            orig_crs = CRS.from_epsg(3413) # North Polar Stereographic from NSIDC
-            target_crs = CRS.from_epsg(4326) # Geographic coordinate system (i.e. lat-lon)
-            # Use pyproj.Transformer to convert from NSIDC projection to lat-lon coordinates
-            transformer = Transformer.from_crs(orig_crs, target_crs)
-            lat_src, lon_src = transformer.transform(x_mask, y_mask)
-            # Assign the new coordinates to the dataset
-            ds_mask = ds_mask.assign_coords({'lon': (['y', 'x'], lon_src), 'lat': (['y', 'x'], lat_src)})
-
         # ------------- Bulk of the function: interpolate the mask to the ds grid -------------
-        # If 'weights' are given, load them directly. If not, calculate them
-        # But since xesmf does not exist yet on `cyclone`, need to deal with it.
-        # try:  # If xesmf exists, create or load the regridder and regrid
-        import xesmf as xe # type: ignore
+        # Import xesmf. Will throw an error if not available
+        import xesmf as xe
+        # Create a regridder.
         Regridder = xe.Regridder(ds_mask, target_grid, method='bilinear')
         # Now apply this regridder to the mask
         ds_mask_interp = Regridder(ds_mask)
-        # except ImportError: # If the import failed, send an error
-            # print("ERROR: xesmf could not be loaded, go to `coriolis`.")
-            # return
-    # return the interpolated mask.
+    # Return the interpolated mask.
     return ds_mask_interp
 
 
 def groupby_sectors(ds, ref=None,
-                    target_gd=None, 
+                    target_gd=None,
                     maskFile=Path.cwd().joinpath('../data/NSIDCRegions_N3.125km_v1.1_wLatLon_df1.nc')):
     """
     Define sectors and Groupby a dataset or dataArray into those sectors. 
diff --git a/src/test_tbxsectors.ipynb b/src/test_tbxsectors.ipynb
index 09ed7623a9616693837317d09c98237a1cef10a4..4aa546465885dd571d31429db422032a758e2e4a 100644
--- a/src/test_tbxsectors.ipynb
+++ b/src/test_tbxsectors.ipynb
@@ -426,14 +426,14 @@
        "    comment:                   SSTs were observed by conventional thermometer...\n",
        "    summary:                   ERSST.v5 is developed based on v4 after revisi...\n",
        "    dataset_title:             NOAA Extended Reconstructed SST V5\n",
-       "    data_modified:             2022-06-07</pre><div class='xr-wrap' style='display:none'><div class='xr-header'><div class='xr-obj-type'>xarray.Dataset</div></div><ul class='xr-sections'><li class='xr-section-item'><input id='section-617b2a36-6a01-43a6-98bc-213f8d857a4e' class='xr-section-summary-in' type='checkbox' disabled ><label for='section-617b2a36-6a01-43a6-98bc-213f8d857a4e' class='xr-section-summary'  title='Expand/collapse section'>Dimensions:</label><div class='xr-section-inline-details'><ul class='xr-dim-list'><li><span class='xr-has-index'>lat</span>: 89</li><li><span class='xr-has-index'>lon</span>: 180</li><li><span class='xr-has-index'>time</span>: 624</li><li><span>nbnds</span>: 2</li></ul></div><div class='xr-section-details'></div></li><li class='xr-section-item'><input id='section-cd075066-2506-42fe-b9e6-918525704870' class='xr-section-summary-in' type='checkbox'  checked><label for='section-cd075066-2506-42fe-b9e6-918525704870' class='xr-section-summary' >Coordinates: <span>(3)</span></label><div class='xr-section-inline-details'></div><div class='xr-section-details'><ul class='xr-var-list'><li class='xr-var-item'><div class='xr-var-name'><span class='xr-has-index'>lat</span></div><div class='xr-var-dims'>(lat)</div><div class='xr-var-dtype'>float32</div><div class='xr-var-preview xr-preview'>88.0 86.0 84.0 ... -86.0 -88.0</div><input id='attrs-80c5e381-20ad-4a3c-93a2-f0a58cf71ddf' class='xr-var-attrs-in' type='checkbox' ><label for='attrs-80c5e381-20ad-4a3c-93a2-f0a58cf71ddf' title='Show/Hide attributes'><svg class='icon xr-icon-file-text2'><use xlink:href='#icon-file-text2'></use></svg></label><input id='data-4c3a98f7-ae4e-4fdb-ab63-4c0dfcdd8804' class='xr-var-data-in' type='checkbox'><label for='data-4c3a98f7-ae4e-4fdb-ab63-4c0dfcdd8804' title='Show/Hide data repr'><svg class='icon xr-icon-database'><use xlink:href='#icon-database'></use></svg></label><div class='xr-var-attrs'><dl class='xr-attrs'><dt><span>units :</span></dt><dd>degrees_north</dd><dt><span>long_name :</span></dt><dd>Latitude</dd><dt><span>actual_range :</span></dt><dd>[ 88. -88.]</dd><dt><span>standard_name :</span></dt><dd>latitude</dd><dt><span>axis :</span></dt><dd>Y</dd><dt><span>coordinate_defines :</span></dt><dd>center</dd></dl></div><div class='xr-var-data'><pre>array([ 88.,  86.,  84.,  82.,  80.,  78.,  76.,  74.,  72.,  70.,  68.,  66.,\n",
+       "    data_modified:             2022-06-07</pre><div class='xr-wrap' style='display:none'><div class='xr-header'><div class='xr-obj-type'>xarray.Dataset</div></div><ul class='xr-sections'><li class='xr-section-item'><input id='section-81559d84-6a3c-4a43-a7e8-65f5079f799a' class='xr-section-summary-in' type='checkbox' disabled ><label for='section-81559d84-6a3c-4a43-a7e8-65f5079f799a' class='xr-section-summary'  title='Expand/collapse section'>Dimensions:</label><div class='xr-section-inline-details'><ul class='xr-dim-list'><li><span class='xr-has-index'>lat</span>: 89</li><li><span class='xr-has-index'>lon</span>: 180</li><li><span class='xr-has-index'>time</span>: 624</li><li><span>nbnds</span>: 2</li></ul></div><div class='xr-section-details'></div></li><li class='xr-section-item'><input id='section-b9866729-ac90-4bf4-88d9-f80de0a7de78' class='xr-section-summary-in' type='checkbox'  checked><label for='section-b9866729-ac90-4bf4-88d9-f80de0a7de78' class='xr-section-summary' >Coordinates: <span>(3)</span></label><div class='xr-section-inline-details'></div><div class='xr-section-details'><ul class='xr-var-list'><li class='xr-var-item'><div class='xr-var-name'><span class='xr-has-index'>lat</span></div><div class='xr-var-dims'>(lat)</div><div class='xr-var-dtype'>float32</div><div class='xr-var-preview xr-preview'>88.0 86.0 84.0 ... -86.0 -88.0</div><input id='attrs-20bc68b0-f9eb-417e-b43b-b63332a0b822' class='xr-var-attrs-in' type='checkbox' ><label for='attrs-20bc68b0-f9eb-417e-b43b-b63332a0b822' title='Show/Hide attributes'><svg class='icon xr-icon-file-text2'><use xlink:href='#icon-file-text2'></use></svg></label><input id='data-f0c66eae-4c07-4dd7-a118-82e4c65c844d' class='xr-var-data-in' type='checkbox'><label for='data-f0c66eae-4c07-4dd7-a118-82e4c65c844d' title='Show/Hide data repr'><svg class='icon xr-icon-database'><use xlink:href='#icon-database'></use></svg></label><div class='xr-var-attrs'><dl class='xr-attrs'><dt><span>units :</span></dt><dd>degrees_north</dd><dt><span>long_name :</span></dt><dd>Latitude</dd><dt><span>actual_range :</span></dt><dd>[ 88. -88.]</dd><dt><span>standard_name :</span></dt><dd>latitude</dd><dt><span>axis :</span></dt><dd>Y</dd><dt><span>coordinate_defines :</span></dt><dd>center</dd></dl></div><div class='xr-var-data'><pre>array([ 88.,  86.,  84.,  82.,  80.,  78.,  76.,  74.,  72.,  70.,  68.,  66.,\n",
        "        64.,  62.,  60.,  58.,  56.,  54.,  52.,  50.,  48.,  46.,  44.,  42.,\n",
        "        40.,  38.,  36.,  34.,  32.,  30.,  28.,  26.,  24.,  22.,  20.,  18.,\n",
        "        16.,  14.,  12.,  10.,   8.,   6.,   4.,   2.,   0.,  -2.,  -4.,  -6.,\n",
        "        -8., -10., -12., -14., -16., -18., -20., -22., -24., -26., -28., -30.,\n",
        "       -32., -34., -36., -38., -40., -42., -44., -46., -48., -50., -52., -54.,\n",
        "       -56., -58., -60., -62., -64., -66., -68., -70., -72., -74., -76., -78.,\n",
-       "       -80., -82., -84., -86., -88.], dtype=float32)</pre></div></li><li class='xr-var-item'><div class='xr-var-name'><span class='xr-has-index'>lon</span></div><div class='xr-var-dims'>(lon)</div><div class='xr-var-dtype'>float32</div><div class='xr-var-preview xr-preview'>0.0 2.0 4.0 ... 354.0 356.0 358.0</div><input id='attrs-1047f3d1-8a6b-4f71-be07-e50552553ee3' class='xr-var-attrs-in' type='checkbox' ><label for='attrs-1047f3d1-8a6b-4f71-be07-e50552553ee3' title='Show/Hide attributes'><svg class='icon xr-icon-file-text2'><use xlink:href='#icon-file-text2'></use></svg></label><input id='data-054f9696-a55e-4b93-af02-5fe10e1c189e' class='xr-var-data-in' type='checkbox'><label for='data-054f9696-a55e-4b93-af02-5fe10e1c189e' title='Show/Hide data repr'><svg class='icon xr-icon-database'><use xlink:href='#icon-database'></use></svg></label><div class='xr-var-attrs'><dl class='xr-attrs'><dt><span>units :</span></dt><dd>degrees_east</dd><dt><span>long_name :</span></dt><dd>Longitude</dd><dt><span>actual_range :</span></dt><dd>[  0. 358.]</dd><dt><span>standard_name :</span></dt><dd>longitude</dd><dt><span>axis :</span></dt><dd>X</dd><dt><span>coordinate_defines :</span></dt><dd>center</dd></dl></div><div class='xr-var-data'><pre>array([  0.,   2.,   4.,   6.,   8.,  10.,  12.,  14.,  16.,  18.,  20.,  22.,\n",
+       "       -80., -82., -84., -86., -88.], dtype=float32)</pre></div></li><li class='xr-var-item'><div class='xr-var-name'><span class='xr-has-index'>lon</span></div><div class='xr-var-dims'>(lon)</div><div class='xr-var-dtype'>float32</div><div class='xr-var-preview xr-preview'>0.0 2.0 4.0 ... 354.0 356.0 358.0</div><input id='attrs-3900fac9-18ef-47d7-b685-536223b1d714' class='xr-var-attrs-in' type='checkbox' ><label for='attrs-3900fac9-18ef-47d7-b685-536223b1d714' title='Show/Hide attributes'><svg class='icon xr-icon-file-text2'><use xlink:href='#icon-file-text2'></use></svg></label><input id='data-f8a1997f-f32a-4d5f-a348-4e89a672c680' class='xr-var-data-in' type='checkbox'><label for='data-f8a1997f-f32a-4d5f-a348-4e89a672c680' title='Show/Hide data repr'><svg class='icon xr-icon-database'><use xlink:href='#icon-database'></use></svg></label><div class='xr-var-attrs'><dl class='xr-attrs'><dt><span>units :</span></dt><dd>degrees_east</dd><dt><span>long_name :</span></dt><dd>Longitude</dd><dt><span>actual_range :</span></dt><dd>[  0. 358.]</dd><dt><span>standard_name :</span></dt><dd>longitude</dd><dt><span>axis :</span></dt><dd>X</dd><dt><span>coordinate_defines :</span></dt><dd>center</dd></dl></div><div class='xr-var-data'><pre>array([  0.,   2.,   4.,   6.,   8.,  10.,  12.,  14.,  16.,  18.,  20.,  22.,\n",
        "        24.,  26.,  28.,  30.,  32.,  34.,  36.,  38.,  40.,  42.,  44.,  46.,\n",
        "        48.,  50.,  52.,  54.,  56.,  58.,  60.,  62.,  64.,  66.,  68.,  70.,\n",
        "        72.,  74.,  76.,  78.,  80.,  82.,  84.,  86.,  88.,  90.,  92.,  94.,\n",
@@ -448,10 +448,10 @@
        "       288., 290., 292., 294., 296., 298., 300., 302., 304., 306., 308., 310.,\n",
        "       312., 314., 316., 318., 320., 322., 324., 326., 328., 330., 332., 334.,\n",
        "       336., 338., 340., 342., 344., 346., 348., 350., 352., 354., 356., 358.],\n",
-       "      dtype=float32)</pre></div></li><li class='xr-var-item'><div class='xr-var-name'><span class='xr-has-index'>time</span></div><div class='xr-var-dims'>(time)</div><div class='xr-var-dtype'>datetime64[ns]</div><div class='xr-var-preview xr-preview'>1970-01-01 ... 2021-12-01</div><input id='attrs-86445ef8-0794-4eb0-ad7a-e2b196a7d734' class='xr-var-attrs-in' type='checkbox' ><label for='attrs-86445ef8-0794-4eb0-ad7a-e2b196a7d734' title='Show/Hide attributes'><svg class='icon xr-icon-file-text2'><use xlink:href='#icon-file-text2'></use></svg></label><input id='data-d0688bd1-41d4-46ee-883d-608aa3a9cbee' class='xr-var-data-in' type='checkbox'><label for='data-d0688bd1-41d4-46ee-883d-608aa3a9cbee' title='Show/Hide data repr'><svg class='icon xr-icon-database'><use xlink:href='#icon-database'></use></svg></label><div class='xr-var-attrs'><dl class='xr-attrs'><dt><span>long_name :</span></dt><dd>Time</dd><dt><span>delta_t :</span></dt><dd>0000-01-00 00:00:00</dd><dt><span>avg_period :</span></dt><dd>0000-01-00 00:00:00</dd><dt><span>prev_avg_period :</span></dt><dd>0000-00-07 00:00:00</dd><dt><span>standard_name :</span></dt><dd>time</dd><dt><span>axis :</span></dt><dd>T</dd><dt><span>actual_range :</span></dt><dd>[19723. 81204.]</dd></dl></div><div class='xr-var-data'><pre>array([&#x27;1970-01-01T00:00:00.000000000&#x27;, &#x27;1970-02-01T00:00:00.000000000&#x27;,\n",
+       "      dtype=float32)</pre></div></li><li class='xr-var-item'><div class='xr-var-name'><span class='xr-has-index'>time</span></div><div class='xr-var-dims'>(time)</div><div class='xr-var-dtype'>datetime64[ns]</div><div class='xr-var-preview xr-preview'>1970-01-01 ... 2021-12-01</div><input id='attrs-761df052-15dd-4f9d-a3eb-9dd198584c9b' class='xr-var-attrs-in' type='checkbox' ><label for='attrs-761df052-15dd-4f9d-a3eb-9dd198584c9b' title='Show/Hide attributes'><svg class='icon xr-icon-file-text2'><use xlink:href='#icon-file-text2'></use></svg></label><input id='data-0d453433-b763-4d9f-9d71-791e6126d401' class='xr-var-data-in' type='checkbox'><label for='data-0d453433-b763-4d9f-9d71-791e6126d401' title='Show/Hide data repr'><svg class='icon xr-icon-database'><use xlink:href='#icon-database'></use></svg></label><div class='xr-var-attrs'><dl class='xr-attrs'><dt><span>long_name :</span></dt><dd>Time</dd><dt><span>delta_t :</span></dt><dd>0000-01-00 00:00:00</dd><dt><span>avg_period :</span></dt><dd>0000-01-00 00:00:00</dd><dt><span>prev_avg_period :</span></dt><dd>0000-00-07 00:00:00</dd><dt><span>standard_name :</span></dt><dd>time</dd><dt><span>axis :</span></dt><dd>T</dd><dt><span>actual_range :</span></dt><dd>[19723. 81204.]</dd></dl></div><div class='xr-var-data'><pre>array([&#x27;1970-01-01T00:00:00.000000000&#x27;, &#x27;1970-02-01T00:00:00.000000000&#x27;,\n",
        "       &#x27;1970-03-01T00:00:00.000000000&#x27;, ..., &#x27;2021-10-01T00:00:00.000000000&#x27;,\n",
        "       &#x27;2021-11-01T00:00:00.000000000&#x27;, &#x27;2021-12-01T00:00:00.000000000&#x27;],\n",
-       "      dtype=&#x27;datetime64[ns]&#x27;)</pre></div></li></ul></div></li><li class='xr-section-item'><input id='section-21e2d998-912a-4b2b-922b-5cf328c110de' class='xr-section-summary-in' type='checkbox'  checked><label for='section-21e2d998-912a-4b2b-922b-5cf328c110de' class='xr-section-summary' >Data variables: <span>(2)</span></label><div class='xr-section-inline-details'></div><div class='xr-section-details'><ul class='xr-var-list'><li class='xr-var-item'><div class='xr-var-name'><span>time_bnds</span></div><div class='xr-var-dims'>(time, nbnds)</div><div class='xr-var-dtype'>float64</div><div class='xr-var-preview xr-preview'>...</div><input id='attrs-e312316b-f460-4cda-b92d-ec1def9a42f4' class='xr-var-attrs-in' type='checkbox' ><label for='attrs-e312316b-f460-4cda-b92d-ec1def9a42f4' title='Show/Hide attributes'><svg class='icon xr-icon-file-text2'><use xlink:href='#icon-file-text2'></use></svg></label><input id='data-c469ad2d-0dc0-4979-a8b3-35316a3217e0' class='xr-var-data-in' type='checkbox'><label for='data-c469ad2d-0dc0-4979-a8b3-35316a3217e0' title='Show/Hide data repr'><svg class='icon xr-icon-database'><use xlink:href='#icon-database'></use></svg></label><div class='xr-var-attrs'><dl class='xr-attrs'><dt><span>long_name :</span></dt><dd>Time Boundaries</dd></dl></div><div class='xr-var-data'><pre>[1248 values with dtype=float64]</pre></div></li><li class='xr-var-item'><div class='xr-var-name'><span>sst</span></div><div class='xr-var-dims'>(time, lat, lon)</div><div class='xr-var-dtype'>float32</div><div class='xr-var-preview xr-preview'>...</div><input id='attrs-11fa0d23-edea-4794-9d46-e29961a5263a' class='xr-var-attrs-in' type='checkbox' ><label for='attrs-11fa0d23-edea-4794-9d46-e29961a5263a' title='Show/Hide attributes'><svg class='icon xr-icon-file-text2'><use xlink:href='#icon-file-text2'></use></svg></label><input id='data-895cabfb-d4c4-4135-9044-74d9d9bab8e7' class='xr-var-data-in' type='checkbox'><label for='data-895cabfb-d4c4-4135-9044-74d9d9bab8e7' title='Show/Hide data repr'><svg class='icon xr-icon-database'><use xlink:href='#icon-database'></use></svg></label><div class='xr-var-attrs'><dl class='xr-attrs'><dt><span>long_name :</span></dt><dd>Monthly Means of Sea Surface Temperature</dd><dt><span>units :</span></dt><dd>degC</dd><dt><span>var_desc :</span></dt><dd>Sea Surface Temperature</dd><dt><span>level_desc :</span></dt><dd>Surface</dd><dt><span>statistic :</span></dt><dd>Mean</dd><dt><span>dataset :</span></dt><dd>NOAA Extended Reconstructed SST V5</dd><dt><span>parent_stat :</span></dt><dd>Individual Values</dd><dt><span>actual_range :</span></dt><dd>[-1.8     42.32636]</dd><dt><span>valid_range :</span></dt><dd>[-1.8 45. ]</dd></dl></div><div class='xr-var-data'><pre>[9996480 values with dtype=float32]</pre></div></li></ul></div></li><li class='xr-section-item'><input id='section-b758896a-0afa-4f90-ade3-9ffa41c4d304' class='xr-section-summary-in' type='checkbox'  ><label for='section-b758896a-0afa-4f90-ade3-9ffa41c4d304' class='xr-section-summary' >Indexes: <span>(3)</span></label><div class='xr-section-inline-details'></div><div class='xr-section-details'><ul class='xr-var-list'><li class='xr-var-item'><div class='xr-index-name'><div>lat</div></div><div class='xr-index-preview'>PandasIndex</div><div></div><input id='index-603ec69e-ff36-4a44-8299-137afdf32a3c' class='xr-index-data-in' type='checkbox'/><label for='index-603ec69e-ff36-4a44-8299-137afdf32a3c' title='Show/Hide index repr'><svg class='icon xr-icon-database'><use xlink:href='#icon-database'></use></svg></label><div class='xr-index-data'><pre>PandasIndex(Float64Index([ 88.0,  86.0,  84.0,  82.0,  80.0,  78.0,  76.0,  74.0,  72.0,\n",
+       "      dtype=&#x27;datetime64[ns]&#x27;)</pre></div></li></ul></div></li><li class='xr-section-item'><input id='section-818c9d07-6279-4381-a159-dfddcdabbedb' class='xr-section-summary-in' type='checkbox'  checked><label for='section-818c9d07-6279-4381-a159-dfddcdabbedb' class='xr-section-summary' >Data variables: <span>(2)</span></label><div class='xr-section-inline-details'></div><div class='xr-section-details'><ul class='xr-var-list'><li class='xr-var-item'><div class='xr-var-name'><span>time_bnds</span></div><div class='xr-var-dims'>(time, nbnds)</div><div class='xr-var-dtype'>float64</div><div class='xr-var-preview xr-preview'>...</div><input id='attrs-0183bb35-9dbc-405f-b0c4-ff1e9dcb3cf1' class='xr-var-attrs-in' type='checkbox' ><label for='attrs-0183bb35-9dbc-405f-b0c4-ff1e9dcb3cf1' title='Show/Hide attributes'><svg class='icon xr-icon-file-text2'><use xlink:href='#icon-file-text2'></use></svg></label><input id='data-d6e0cf86-3f5c-474b-adb1-9f2ebc705836' class='xr-var-data-in' type='checkbox'><label for='data-d6e0cf86-3f5c-474b-adb1-9f2ebc705836' title='Show/Hide data repr'><svg class='icon xr-icon-database'><use xlink:href='#icon-database'></use></svg></label><div class='xr-var-attrs'><dl class='xr-attrs'><dt><span>long_name :</span></dt><dd>Time Boundaries</dd></dl></div><div class='xr-var-data'><pre>[1248 values with dtype=float64]</pre></div></li><li class='xr-var-item'><div class='xr-var-name'><span>sst</span></div><div class='xr-var-dims'>(time, lat, lon)</div><div class='xr-var-dtype'>float32</div><div class='xr-var-preview xr-preview'>...</div><input id='attrs-f054578a-4302-4cb9-836c-13bfd82bc991' class='xr-var-attrs-in' type='checkbox' ><label for='attrs-f054578a-4302-4cb9-836c-13bfd82bc991' title='Show/Hide attributes'><svg class='icon xr-icon-file-text2'><use xlink:href='#icon-file-text2'></use></svg></label><input id='data-8a48391d-5ce6-4c88-957f-79ed97be7bd6' class='xr-var-data-in' type='checkbox'><label for='data-8a48391d-5ce6-4c88-957f-79ed97be7bd6' title='Show/Hide data repr'><svg class='icon xr-icon-database'><use xlink:href='#icon-database'></use></svg></label><div class='xr-var-attrs'><dl class='xr-attrs'><dt><span>long_name :</span></dt><dd>Monthly Means of Sea Surface Temperature</dd><dt><span>units :</span></dt><dd>degC</dd><dt><span>var_desc :</span></dt><dd>Sea Surface Temperature</dd><dt><span>level_desc :</span></dt><dd>Surface</dd><dt><span>statistic :</span></dt><dd>Mean</dd><dt><span>dataset :</span></dt><dd>NOAA Extended Reconstructed SST V5</dd><dt><span>parent_stat :</span></dt><dd>Individual Values</dd><dt><span>actual_range :</span></dt><dd>[-1.8     42.32636]</dd><dt><span>valid_range :</span></dt><dd>[-1.8 45. ]</dd></dl></div><div class='xr-var-data'><pre>[9996480 values with dtype=float32]</pre></div></li></ul></div></li><li class='xr-section-item'><input id='section-6550167f-199c-4477-a012-edbd4a108385' class='xr-section-summary-in' type='checkbox'  ><label for='section-6550167f-199c-4477-a012-edbd4a108385' class='xr-section-summary' >Indexes: <span>(3)</span></label><div class='xr-section-inline-details'></div><div class='xr-section-details'><ul class='xr-var-list'><li class='xr-var-item'><div class='xr-index-name'><div>lat</div></div><div class='xr-index-preview'>PandasIndex</div><div></div><input id='index-7d7c4015-bb4d-49ce-94e1-08bf2a058d55' class='xr-index-data-in' type='checkbox'/><label for='index-7d7c4015-bb4d-49ce-94e1-08bf2a058d55' title='Show/Hide index repr'><svg class='icon xr-icon-database'><use xlink:href='#icon-database'></use></svg></label><div class='xr-index-data'><pre>PandasIndex(Float64Index([ 88.0,  86.0,  84.0,  82.0,  80.0,  78.0,  76.0,  74.0,  72.0,\n",
        "               70.0,  68.0,  66.0,  64.0,  62.0,  60.0,  58.0,  56.0,  54.0,\n",
        "               52.0,  50.0,  48.0,  46.0,  44.0,  42.0,  40.0,  38.0,  36.0,\n",
        "               34.0,  32.0,  30.0,  28.0,  26.0,  24.0,  22.0,  20.0,  18.0,\n",
@@ -461,19 +461,19 @@
        "              -38.0, -40.0, -42.0, -44.0, -46.0, -48.0, -50.0, -52.0, -54.0,\n",
        "              -56.0, -58.0, -60.0, -62.0, -64.0, -66.0, -68.0, -70.0, -72.0,\n",
        "              -74.0, -76.0, -78.0, -80.0, -82.0, -84.0, -86.0, -88.0],\n",
-       "             dtype=&#x27;float64&#x27;, name=&#x27;lat&#x27;))</pre></div></li><li class='xr-var-item'><div class='xr-index-name'><div>lon</div></div><div class='xr-index-preview'>PandasIndex</div><div></div><input id='index-bbea7f43-1180-4025-907c-65db0e9df80f' class='xr-index-data-in' type='checkbox'/><label for='index-bbea7f43-1180-4025-907c-65db0e9df80f' title='Show/Hide index repr'><svg class='icon xr-icon-database'><use xlink:href='#icon-database'></use></svg></label><div class='xr-index-data'><pre>PandasIndex(Float64Index([  0.0,   2.0,   4.0,   6.0,   8.0,  10.0,  12.0,  14.0,  16.0,\n",
+       "             dtype=&#x27;float64&#x27;, name=&#x27;lat&#x27;))</pre></div></li><li class='xr-var-item'><div class='xr-index-name'><div>lon</div></div><div class='xr-index-preview'>PandasIndex</div><div></div><input id='index-8ae9f8f6-3bf0-4d05-873f-f47625c76def' class='xr-index-data-in' type='checkbox'/><label for='index-8ae9f8f6-3bf0-4d05-873f-f47625c76def' title='Show/Hide index repr'><svg class='icon xr-icon-database'><use xlink:href='#icon-database'></use></svg></label><div class='xr-index-data'><pre>PandasIndex(Float64Index([  0.0,   2.0,   4.0,   6.0,   8.0,  10.0,  12.0,  14.0,  16.0,\n",
        "               18.0,\n",
        "              ...\n",
        "              340.0, 342.0, 344.0, 346.0, 348.0, 350.0, 352.0, 354.0, 356.0,\n",
        "              358.0],\n",
-       "             dtype=&#x27;float64&#x27;, name=&#x27;lon&#x27;, length=180))</pre></div></li><li class='xr-var-item'><div class='xr-index-name'><div>time</div></div><div class='xr-index-preview'>PandasIndex</div><div></div><input id='index-1e7ba2f4-8bd2-46e0-b945-51a0a17adae2' class='xr-index-data-in' type='checkbox'/><label for='index-1e7ba2f4-8bd2-46e0-b945-51a0a17adae2' title='Show/Hide index repr'><svg class='icon xr-icon-database'><use xlink:href='#icon-database'></use></svg></label><div class='xr-index-data'><pre>PandasIndex(DatetimeIndex([&#x27;1970-01-01&#x27;, &#x27;1970-02-01&#x27;, &#x27;1970-03-01&#x27;, &#x27;1970-04-01&#x27;,\n",
+       "             dtype=&#x27;float64&#x27;, name=&#x27;lon&#x27;, length=180))</pre></div></li><li class='xr-var-item'><div class='xr-index-name'><div>time</div></div><div class='xr-index-preview'>PandasIndex</div><div></div><input id='index-c37f2c12-162f-409e-afcd-d295c0da6766' class='xr-index-data-in' type='checkbox'/><label for='index-c37f2c12-162f-409e-afcd-d295c0da6766' title='Show/Hide index repr'><svg class='icon xr-icon-database'><use xlink:href='#icon-database'></use></svg></label><div class='xr-index-data'><pre>PandasIndex(DatetimeIndex([&#x27;1970-01-01&#x27;, &#x27;1970-02-01&#x27;, &#x27;1970-03-01&#x27;, &#x27;1970-04-01&#x27;,\n",
        "               &#x27;1970-05-01&#x27;, &#x27;1970-06-01&#x27;, &#x27;1970-07-01&#x27;, &#x27;1970-08-01&#x27;,\n",
        "               &#x27;1970-09-01&#x27;, &#x27;1970-10-01&#x27;,\n",
        "               ...\n",
        "               &#x27;2021-03-01&#x27;, &#x27;2021-04-01&#x27;, &#x27;2021-05-01&#x27;, &#x27;2021-06-01&#x27;,\n",
        "               &#x27;2021-07-01&#x27;, &#x27;2021-08-01&#x27;, &#x27;2021-09-01&#x27;, &#x27;2021-10-01&#x27;,\n",
        "               &#x27;2021-11-01&#x27;, &#x27;2021-12-01&#x27;],\n",
-       "              dtype=&#x27;datetime64[ns]&#x27;, name=&#x27;time&#x27;, length=624, freq=None))</pre></div></li></ul></div></li><li class='xr-section-item'><input id='section-8b69c8d4-a4dc-42dc-8f89-75ebffd8fb92' class='xr-section-summary-in' type='checkbox'  ><label for='section-8b69c8d4-a4dc-42dc-8f89-75ebffd8fb92' class='xr-section-summary' >Attributes: <span>(37)</span></label><div class='xr-section-inline-details'></div><div class='xr-section-details'><dl class='xr-attrs'><dt><span>climatology :</span></dt><dd>Climatology is based on 1971-2000 SST, Xue, Y., T. M. Smith, and R. W. Reynolds, 2003: Interdecadal changes of 30-yr SST normals during 1871.2000. Journal of Climate, 16, 1601-1612.</dd><dt><span>description :</span></dt><dd>In situ data: ICOADS2.5 before 2007 and NCEP in situ data from 2008 to present. Ice data: HadISST ice before 2010 and NCEP ice after 2010.</dd><dt><span>keywords_vocabulary :</span></dt><dd>NASA Global Change Master Directory (GCMD) Science Keywords</dd><dt><span>keywords :</span></dt><dd>Earth Science &gt; Oceans &gt; Ocean Temperature &gt; Sea Surface Temperature &gt;</dd><dt><span>instrument :</span></dt><dd>Conventional thermometers</dd><dt><span>source_comment :</span></dt><dd>SSTs were observed by conventional thermometers in Buckets (insulated or un-insulated canvas and wooded buckets) or Engine Room Intaker</dd><dt><span>geospatial_lon_min :</span></dt><dd>-1.0</dd><dt><span>geospatial_lon_max :</span></dt><dd>359.0</dd><dt><span>geospatial_laty_max :</span></dt><dd>89.0</dd><dt><span>geospatial_laty_min :</span></dt><dd>-89.0</dd><dt><span>geospatial_lat_max :</span></dt><dd>89.0</dd><dt><span>geospatial_lat_min :</span></dt><dd>-89.0</dd><dt><span>geospatial_lat_units :</span></dt><dd>degrees_north</dd><dt><span>geospatial_lon_units :</span></dt><dd>degrees_east</dd><dt><span>cdm_data_type :</span></dt><dd>Grid</dd><dt><span>project :</span></dt><dd>NOAA Extended Reconstructed Sea Surface Temperature (ERSST)</dd><dt><span>original_publisher_url :</span></dt><dd>http://www.ncdc.noaa.gov</dd><dt><span>References :</span></dt><dd>https://www.ncdc.noaa.gov/data-access/marineocean-data/extended-reconstructed-sea-surface-temperature-ersst-v5 at NCEI and http://www.esrl.noaa.gov/psd/data/gridded/data.noaa.ersst.v5.html</dd><dt><span>source :</span></dt><dd>In situ data: ICOADS R3.0 before 2015, NCEP in situ GTS from 2016 to present, and Argo SST from 1999 to present. Ice data: HadISST2 ice before 2015, and NCEP ice after 2015</dd><dt><span>title :</span></dt><dd>NOAA ERSSTv5 (in situ only)</dd><dt><span>history :</span></dt><dd>created 07/2017 by PSD data using NCEI&#x27;s ERSST V5 NetCDF values</dd><dt><span>institution :</span></dt><dd>This version written at NOAA/ESRL PSD: obtained from NOAA/NESDIS/National Centers for Environmental Information and time aggregated. Original Full Source: NOAA/NESDIS/NCEI/CCOG</dd><dt><span>citation :</span></dt><dd>Huang et al, 2017: Extended Reconstructed Sea Surface Temperatures Version 5 (ERSSTv5): Upgrades, Validations, and Intercomparisons. Journal of Climate, https://doi.org/10.1175/JCLI-D-16-0836.1</dd><dt><span>platform :</span></dt><dd>Ship and Buoy SSTs from ICOADS R3.0 and NCEP GTS</dd><dt><span>standard_name_vocabulary :</span></dt><dd>CF Standard Name Table (v40, 25 January 2017)</dd><dt><span>processing_level :</span></dt><dd>NOAA Level 4</dd><dt><span>Conventions :</span></dt><dd>CF-1.6, ACDD-1.3</dd><dt><span>metadata_link :</span></dt><dd>:metadata_link = https://doi.org/10.7289/V5T72FNM (original format)</dd><dt><span>creator_name :</span></dt><dd>Boyin Huang (original)</dd><dt><span>date_created :</span></dt><dd>2017-06-30T12:18:00Z (original)</dd><dt><span>product_version :</span></dt><dd>Version 5</dd><dt><span>creator_url_original :</span></dt><dd>https://www.ncei.noaa.gov</dd><dt><span>license :</span></dt><dd>No constraints on data access or use</dd><dt><span>comment :</span></dt><dd>SSTs were observed by conventional thermometers in Buckets (insulated or un-insulated canvas and wooded buckets), Engine Room Intakers, or floats and drifters</dd><dt><span>summary :</span></dt><dd>ERSST.v5 is developed based on v4 after revisions of 8 parameters using updated data sets and advanced knowledge of ERSST analysis</dd><dt><span>dataset_title :</span></dt><dd>NOAA Extended Reconstructed SST V5</dd><dt><span>data_modified :</span></dt><dd>2022-06-07</dd></dl></div></li></ul></div></div>"
+       "              dtype=&#x27;datetime64[ns]&#x27;, name=&#x27;time&#x27;, length=624, freq=None))</pre></div></li></ul></div></li><li class='xr-section-item'><input id='section-044651d8-9cce-4d4c-ad2c-34ad549915d2' class='xr-section-summary-in' type='checkbox'  ><label for='section-044651d8-9cce-4d4c-ad2c-34ad549915d2' class='xr-section-summary' >Attributes: <span>(37)</span></label><div class='xr-section-inline-details'></div><div class='xr-section-details'><dl class='xr-attrs'><dt><span>climatology :</span></dt><dd>Climatology is based on 1971-2000 SST, Xue, Y., T. M. Smith, and R. W. Reynolds, 2003: Interdecadal changes of 30-yr SST normals during 1871.2000. Journal of Climate, 16, 1601-1612.</dd><dt><span>description :</span></dt><dd>In situ data: ICOADS2.5 before 2007 and NCEP in situ data from 2008 to present. Ice data: HadISST ice before 2010 and NCEP ice after 2010.</dd><dt><span>keywords_vocabulary :</span></dt><dd>NASA Global Change Master Directory (GCMD) Science Keywords</dd><dt><span>keywords :</span></dt><dd>Earth Science &gt; Oceans &gt; Ocean Temperature &gt; Sea Surface Temperature &gt;</dd><dt><span>instrument :</span></dt><dd>Conventional thermometers</dd><dt><span>source_comment :</span></dt><dd>SSTs were observed by conventional thermometers in Buckets (insulated or un-insulated canvas and wooded buckets) or Engine Room Intaker</dd><dt><span>geospatial_lon_min :</span></dt><dd>-1.0</dd><dt><span>geospatial_lon_max :</span></dt><dd>359.0</dd><dt><span>geospatial_laty_max :</span></dt><dd>89.0</dd><dt><span>geospatial_laty_min :</span></dt><dd>-89.0</dd><dt><span>geospatial_lat_max :</span></dt><dd>89.0</dd><dt><span>geospatial_lat_min :</span></dt><dd>-89.0</dd><dt><span>geospatial_lat_units :</span></dt><dd>degrees_north</dd><dt><span>geospatial_lon_units :</span></dt><dd>degrees_east</dd><dt><span>cdm_data_type :</span></dt><dd>Grid</dd><dt><span>project :</span></dt><dd>NOAA Extended Reconstructed Sea Surface Temperature (ERSST)</dd><dt><span>original_publisher_url :</span></dt><dd>http://www.ncdc.noaa.gov</dd><dt><span>References :</span></dt><dd>https://www.ncdc.noaa.gov/data-access/marineocean-data/extended-reconstructed-sea-surface-temperature-ersst-v5 at NCEI and http://www.esrl.noaa.gov/psd/data/gridded/data.noaa.ersst.v5.html</dd><dt><span>source :</span></dt><dd>In situ data: ICOADS R3.0 before 2015, NCEP in situ GTS from 2016 to present, and Argo SST from 1999 to present. Ice data: HadISST2 ice before 2015, and NCEP ice after 2015</dd><dt><span>title :</span></dt><dd>NOAA ERSSTv5 (in situ only)</dd><dt><span>history :</span></dt><dd>created 07/2017 by PSD data using NCEI&#x27;s ERSST V5 NetCDF values</dd><dt><span>institution :</span></dt><dd>This version written at NOAA/ESRL PSD: obtained from NOAA/NESDIS/National Centers for Environmental Information and time aggregated. Original Full Source: NOAA/NESDIS/NCEI/CCOG</dd><dt><span>citation :</span></dt><dd>Huang et al, 2017: Extended Reconstructed Sea Surface Temperatures Version 5 (ERSSTv5): Upgrades, Validations, and Intercomparisons. Journal of Climate, https://doi.org/10.1175/JCLI-D-16-0836.1</dd><dt><span>platform :</span></dt><dd>Ship and Buoy SSTs from ICOADS R3.0 and NCEP GTS</dd><dt><span>standard_name_vocabulary :</span></dt><dd>CF Standard Name Table (v40, 25 January 2017)</dd><dt><span>processing_level :</span></dt><dd>NOAA Level 4</dd><dt><span>Conventions :</span></dt><dd>CF-1.6, ACDD-1.3</dd><dt><span>metadata_link :</span></dt><dd>:metadata_link = https://doi.org/10.7289/V5T72FNM (original format)</dd><dt><span>creator_name :</span></dt><dd>Boyin Huang (original)</dd><dt><span>date_created :</span></dt><dd>2017-06-30T12:18:00Z (original)</dd><dt><span>product_version :</span></dt><dd>Version 5</dd><dt><span>creator_url_original :</span></dt><dd>https://www.ncei.noaa.gov</dd><dt><span>license :</span></dt><dd>No constraints on data access or use</dd><dt><span>comment :</span></dt><dd>SSTs were observed by conventional thermometers in Buckets (insulated or un-insulated canvas and wooded buckets), Engine Room Intakers, or floats and drifters</dd><dt><span>summary :</span></dt><dd>ERSST.v5 is developed based on v4 after revisions of 8 parameters using updated data sets and advanced knowledge of ERSST analysis</dd><dt><span>dataset_title :</span></dt><dd>NOAA Extended Reconstructed SST V5</dd><dt><span>data_modified :</span></dt><dd>2022-06-07</dd></dl></div></li></ul></div></div>"
       ],
       "text/plain": [
        "<xarray.Dataset>\n",
@@ -562,7 +562,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": 10,
    "metadata": {},
    "outputs": [
     {
@@ -641,7 +641,7 @@
     {
      "data": {
       "text/plain": [
-       "<xarray.plot.facetgrid.FacetGrid at 0x7f75f5999ab0>"
+       "<xarray.plot.facetgrid.FacetGrid at 0x7f6c37b0a3e0>"
       ]
      },
      "execution_count": 6,
@@ -720,7 +720,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 9,
+   "execution_count": 8,
    "metadata": {},
    "outputs": [
     {
@@ -729,7 +729,7 @@
        "Text(0.5, 1.02, 'SST Anomalies for each Southern Ocean sector (Raphael & Hobbs 2014 definition)')"
       ]
      },
-     "execution_count": 9,
+     "execution_count": 8,
      "metadata": {},
      "output_type": "execute_result"
     },
@@ -747,6 +747,7 @@
    "source": [
     "# Divide by sector and average directly.\n",
     "da_sst_mean_south = tbsec.groupby_sectors(ds_test.sst, ref='RH').mean()\n",
+    "# Then calculate a climatology and remove it from the SST to get anomalies.\n",
     "da_sst_anom_south = da_sst_mean_south.groupby('time.month') - da_sst_mean_south.groupby('time.month').mean()\n",
     "# Plot the time series anomalies\n",
     "gs = da_sst_anom_south.plot(col='sector', col_wrap=3)\n",