Add reader for ASTER/MODIS CAMEL emissivity datasets.

satpy/etc/readers/camel_l3_nc.yaml

@@ -0,0 +1,147 @@
+reader:
+  name: camel_l3_nc
+  short_name: CAMEL L3
+  long_name: CAMEL emissivity level 3 data in netCDF4 format.
+  description: >
+    Reader for the CAMEL emissivity product, produced from various L2/L3
+    datasets on a monthly basis. More details
+    `here <https://lpdaac.usgs.gov/products/cam5k30emv002/>`_.
+  status: Nominal
+  supports_fsspec: false
+  sensors: [combined]
+  reader: !!python/name:satpy.readers.yaml_reader.FileYAMLReader
+
+file_types:
+    camel_emis_file:
+        file_reader: !!python/name:satpy.readers.camel_l3_nc.CAMELL3NCFileHandler
+        file_patterns:
+         - 'CAM5K30EM_emis_{start_time:%Y%m}_V{version:3s}.nc'
+
+
+datasets:
+  # QA products
+  aster_ndvi:
+    name: aster_ndvi
+    file_key: aster_ndvi
+    file_type: [ camel_emis_file ]
+  aster_qflag:
+    name: aster_qflag
+    file_key: aster_qflag
+    file_type: [ camel_emis_file ]
+  bfemis_qflag:
+    name: bfemis_qflag
+    file_key: bfemis_qflag
+    file_type: [ camel_emis_file ]
+  camel_qflag:
+    name: camel_qflag
+    file_key: camel_qflag
+    file_type: [ camel_emis_file ]
+  snow_fraction:
+    name: snow_fraction
+    file_key: snow_fraction
+    file_type: [ camel_emis_file ]
+
+  # Emissivity bands
+  camel_emis_b1:
+    name: camel_emis_b1
+    file_key: camel_emis
+    band_id: 0
+    file_type: [ camel_emis_file ]
+    wavelength: 3.6
+    resolution: 0.05
+
+  camel_emis_b2:
+    name: camel_emis_b2
+    file_key: camel_emis
+    band_id: 1
+    file_type: [ camel_emis_file ]
+    wavelength: 4.3
+    resolution: 0.05
+
+  camel_emis_b3:
+    name: camel_emis_b3
+    file_key: camel_emis
+    band_id: 2
+    file_type: [ camel_emis_file ]
+    wavelength: 5.0
+    resolution: 0.05
+
+  camel_emis_b4:
+    name: camel_emis_b4
+    file_key: camel_emis
+    band_id: 3
+    file_type: [ camel_emis_file ]
+    wavelength: 5.8
+    resolution: 0.05
+
+  camel_emis_b5:
+    name: camel_emis_b5
+    file_key: camel_emis
+    band_id: 4
+    file_type: [ camel_emis_file ]
+    wavelength: 7.6
+    resolution: 0.05
+
+  camel_emis_b6:
+    name: camel_emis_b6
+    file_key: camel_emis
+    band_id: 5
+    file_type: [ camel_emis_file ]
+    wavelength: 8.3
+    resolution: 0.05
+
+  camel_emis_b7:
+    name: camel_emis_b7
+    file_key: camel_emis
+    band_id: 6
+    file_type: [ camel_emis_file ]
+    wavelength: 8.6
+    resolution: 0.05
+
+  camel_emis_b8:
+    name: camel_emis_b8
+    file_key: camel_emis
+    band_id: 7
+    file_type: [ camel_emis_file ]
+    wavelength: 9.1
+    resolution: 0.05
+
+  camel_emis_b9:
+    name: camel_emis_b9
+    file_key: camel_emis
+    band_id: 8
+    file_type: [ camel_emis_file ]
+    wavelength: 10.6
+    resolution: 0.05
+
+  camel_emis_b10:
+    name: camel_emis_b10
+    file_key: camel_emis
+    band_id: 9
+    file_type: [ camel_emis_file ]
+    wavelength: 10.8
+    resolution: 0.05
+
+  camel_emis_b11:
+    name: camel_emis_b11
+    file_key: camel_emis
+    band_id: 10
+    file_type: [ camel_emis_file ]
+    wavelength: 11.3
+    resolution: 0.05
+
+  camel_emis_b12:
+    name: camel_emis_b12
+    file_key: camel_emis
+    band_id: 11
+    file_type: [ camel_emis_file ]
+    wavelength: 12.1
+    resolution: 0.05
+
+  camel_emis_b13:
+    name: camel_emis_b13
+    file_key: camel_emis
+    band_id: 12
+    file_type: [ camel_emis_file ]
+    wavelength: 14.3
+    resolution: 0.05

satpy/readers/camel_l3_nc.py

@@ -0,0 +1,106 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+# Copyright (c) 2024 Satpy developers
+#
+# This file is part of satpy.
+#
+# satpy is free software: you can redistribute it and/or modify it under the
+# terms of the GNU General Public License as published by the Free Software
+# Foundation, either version 3 of the License, or (at your option) any later
+# version.
+#
+# satpy is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+# A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along with
+# satpy.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Reader for CAMEL Level 3 emissivity files in netCDF4 format.
+
+For more information about the data, see: <https://lpdaac.usgs.gov/products/cam5k30emv002/>.
+
+NOTE: This reader only supports the global 0.05 degree grid data.
+"""
+
+
+import datetime as dt
+import logging
+
+import xarray as xr
+from pyresample import geometry
+
+from satpy.readers.file_handlers import BaseFileHandler
+
+logger = logging.getLogger(__name__)
+
+# Area extent for the CAMEL product (global)
+GLOB_AREA_EXT = [-180, -90, 180, 90]
+
+
+class CAMELL3NCFileHandler(BaseFileHandler):
+    """File handler for Himawari L2 NOAA enterprise data in netCDF format."""
+
+    def __init__(self, filename, filename_info, filetype_info):
+        """Initialize the reader."""
+        super().__init__(filename, filename_info, filetype_info)
+        self.nc = xr.open_dataset(self.filename,
+                                  decode_cf=True,
+                                  mask_and_scale=True,
+                                  chunks={"xc": "auto", "yc": "auto"})
+
+        if self.nc.attrs["geospatial_lon_resolution"] != "0.05 degree grid ":
+            raise ValueError("Only 0.05 degree grid data is supported.")
+        if self.nc.attrs["geospatial_lat_resolution"] != "0.05 degree grid ":
+            raise ValueError("Only 0.05 degree grid data is supported.")
+        if self.nc.sizes["spectra"] != 13:
+            raise ValueError("Only CAMEL files with 13 spectral bands are supported.")
+
+        self.nlines = self.nc.sizes["latitude"]
+        self.ncols = self.nc.sizes["longitude"]
+        self.area = None
+
+
+    @property
+    def start_time(self):
+        """Start timestamp of the dataset."""
+        date_str = self.nc.attrs["time_coverage_start"]
+        return dt.datetime.strptime(date_str, "%Y-%m-%d %H:%M:%SZ")
+
+    @property
+    def end_time(self):
+        """End timestamp of the dataset."""
+        date_str = self.nc.attrs["time_coverage_end"]
+        return dt.datetime.strptime(date_str, "%Y-%m-%d %H:%M:%SZ")
+
+
+    def get_dataset(self, key, info):
+        """Load a dataset."""
+        var = info["file_key"]
+        logger.debug("Reading in get_dataset %s.", var)
+        variable = self.nc[var]
+
+        # For the emissivity there are multiple bands, so we need to select the correct one
+        if var == "camel_emis":
+            variable = variable[:, :, info["band_id"]]
+
+        # Rename the latitude and longitude dimensions to x and y
+        variable = variable.rename({"latitude": "y", "longitude": "x"})
+
+        variable.attrs.update(key.to_dict())
+        return variable
+
+
+    def get_area_def(self, dsid):
+        """Get the area definition, a global lat/lon area for this type of dataset."""
+        proj_param = "EPSG:4326"
+
+        area = geometry.AreaDefinition("gridded_camel",
+                                       "A global gridded area",
+                                       "longlat",
+                                       proj_param,
+                                       self.ncols,
+                                       self.nlines,
+                                       GLOB_AREA_EXT)
+        self.area = area
+        return area