Add MiRS reader

satpy/etc/readers/mirs.yaml

@@ -5,6 +5,11 @@ reader:
   long_name: MiRS Level 2 Swath Product Reader (NetCDF4)
   reader: !!python/name:satpy.readers.yaml_reader.FileYAMLReader
   sensors: [amsu, amsu-mhs, atms, ssmis, gmi]
+  data_files:
+     - url: "https://zenodo.org/record/4472664/files/limbcoef_atmsland_noaa20.txt"
+     - url: "https://zenodo.org/record/4472664/files/limbcoef_atmsland_snpp.txt"
+     - url: "https://zenodo.org/record/4472664/files/limbcoef_atmssea_noaa20.txt"
+     - url: "https://zenodo.org/record/4472664/files/limbcoef_atmssea_snpp.txt"
 
 file_types:
   mirs_atms:

satpy/readers/mirs.py

@@ -18,16 +18,20 @@
 """Interface to MiRS product."""
 
 import os
+import re
 import logging
 import datetime
+import appdirs
 import numpy as np
 import xarray as xr
 import dask.array as da
 from satpy import CHUNK_SIZE
 from satpy.readers.file_handlers import BaseFileHandler
+from satpy.aux_download import find_registerable_files, retrieve
 
 LOG = logging.getLogger(__name__)
 logging.basicConfig(level=logging.DEBUG)
+SATPY_DATA_DIR = appdirs.user_data_dir("satpy")
 
 try:
     # try getting setuptools/distribute's version of resource retrieval first
@@ -189,9 +193,7 @@ def __init__(self, filename, filename_info, filetype_info):
 
         self.platform_name = self._get_platform_name
         self.sensor = self._get_sensor
-        self.lons = None
-        self.lats = None
-        self.coords = {}
+        self.coeffs = self.coeff_filenames
 
     def new_coords(self):
         """Define coordinates when file does not use variable attributes."""
@@ -256,6 +258,28 @@ def end_time(self):
             self.filename_info["end_time"] = end_time
         return self.filename_info["end_time"]
 
+    @property
+    def coeff_filenames(self):
+        """Retrieve necessary files for coefficients if needed."""
+        found_files = find_registerable_files(readers=['mirs'], writers=[],
+                                              composite_sensors=[])
+        if self.platform_name == "noaa-20":
+            platform_files = list(filter(lambda x: re.findall('noaa20', x),
+                                         found_files))
+        if self.platform_name == 'npp':
+            platform_files = list(filter(lambda x: re.findall('snpp', x),
+                                         found_files))
+        coeff_fn = {'sea': None, 'land': None}
+
+        for filename in platform_files:
+            if "atmssea" in filename:
+                coeff_fn['sea'] = retrieve(filename)
+            elif "atmsland" in filename:
+                coeff_fn['land'] = retrieve(filename)
+            else:
+                LOG.warning('Unknown coefficient filename {}', filename)
+        return coeff_fn
+
     def force_date(self, key):
         """Force datetime.date for combine."""
         if isinstance(self.filename_info[key], datetime.datetime):
@@ -285,10 +309,10 @@ def limb_correct_atms_bt(self, bt_data, ds_info):
         surf_type_name = deps[1]
         surf_type_mask = self[surf_type_name]
 
-        sea = read_atms_limb_correction_coeffs(LIMB_SEA_FILE)
+        sea = read_atms_limb_correction_coeffs(self.coeffs['sea'])
         sea_bt = apply_atms_limb_correction(bt_data, idx, *sea)
 
-        land = read_atms_limb_correction_coeffs(LIMB_LAND_FILE)
+        land = read_atms_limb_correction_coeffs(self.coeffs['land'])
         land_bt = apply_atms_limb_correction(bt_data, idx, *land)
 
         LOG.info("Finishing limb correction")
@@ -359,13 +383,7 @@ def get_dataset(self, ds_id, ds_info):
             LOG.debug('Calc {} {}'.format(idx, ds_id))
             data = data.rename(new_name_or_name_dict=ds_info["name"])
 
-            # only correct for 'BT' data
-            if 'BT' not in ds_info['dependencies']:
-                do_not_apply = True
-            else:
-                do_not_apply = True   # TODO:  Change this to false when coeff loc is resolved.
-
-            if self.sensor.lower() != "atms" or do_not_apply:
+            if self.sensor.lower() != "atms":
                 LOG.info("Limb Correction will not be applied to non-ATMS BTs")
                 data = data[:, :, idx]
             else:
@@ -402,19 +420,22 @@ def _available_new_datasets(self):
                     freq = self.nc.coords.get('Freq', self.nc.get('Freq'))
                     polo = self.nc['Polo']
                     from collections import Counter
-                    c = Counter()
+                    # count times a channel/polarization pair occur
+                    chn_total = Counter()
                     normals = []
                     for idx, (f, p) in enumerate(zip(freq, polo)):
                         normal_f = str(int(f))
                         normal_p = 'v' if p == POLO_V else 'h'
-                        c[normal_f + normal_p] += 1
+                        chn_total[normal_f + normal_p] += 1
                         normals.append((idx, f, p, normal_f, normal_p))
 
-                    c2 = Counter()
+                    # keep track of current channel count for string description
+                    chn_cnt = Counter()
                     for idx, _f, _p, normal_f, normal_p in normals:
-                        c2[normal_f + normal_p] += 1
-                        p_count = str(c2[normal_f + normal_p]
-                                      if c[normal_f + normal_p] > 1 else '')
+                        chn_cnt[normal_f + normal_p] += 1
+                        p_count = str(chn_cnt[normal_f + normal_p]
+                                      if chn_total[normal_f + normal_p] > 1
+                                      else '')
 
                         new_name = "btemp_{}{}{}".format(normal_f,
                                                          normal_p,
@@ -486,17 +507,8 @@ def __getitem__(self, item):
         data, attrs = self._scale_data(data, attrs)
         data, attrs = self._fill_data(data, attrs)
 
-        # handle coordinates (and recursive fun)
-        new_coords = {}
-        # 'time' dimension causes issues in other processing
+        # 'Freq' dimension causes issues in other processing
         if 'Freq' in data.coords:
             data = data.drop_vars('Freq')
-        if item in data.coords:
-            self.coords[item] = data
-        for coord_name in data.coords.keys():
-            if coord_name not in self.coords:
-                self.coords[coord_name] = self[coord_name]
-            new_coords[coord_name] = self.coords[coord_name]
-
-        data.coords.update(new_coords)
+
         return data