Add a RSR convert script for FY-4B GHI sensor

AUTHORS.md

@@ -19,3 +19,4 @@ The following people have made contributions to this project:
 - [Xin Zhang (zxdawn)](https://github.com/zxdawn)
 - [Rolf Helge Pfeiffer](https://github.com/HelgeCPH)
 - [Antonio Valentino](https://github.com/avalentino)
+- [Lu Liu (yukaribbba)](https://github.com/yukaribbba)

pyspectral/etc/pyspectral.yaml

@@ -249,6 +249,16 @@ download_from_internet: True
 #     ch14: FY4B_AGRI_SRF_CH14_Pub.txt
 #     ch15: FY4B_AGRI_SRF_CH15_Pub.txt
 
+# FY-4B-ghi:
+    # path: D:/satpy_config/FY4B_GHI_SRF
+    # ch1: FY4B_GHI_SRF_CH01_Pub.txt
+    # ch2: FY4B_GHI_SRF_CH02_Pub.txt
+    # ch3: FY4B_GHI_SRF_CH03_Pub.txt
+    # ch4: FY4B_GHI_SRF_CH04_Pub.txt
+    # ch5: FY4B_GHI_SRF_CH05_Pub.txt
+    # ch6: FY4B_GHI_SRF_CH06_Pub.txt
+    # ch7: FY4B_GHI_SRF_CH07_Pub.txt
+
 #Electro-L-N2-msu-gs:
 #     path: /path/to/rsrs/rtcoef_electro-l_2_msugs_srf/
 #     ch1: rtcoef_electro-l_2_msugs_srf_ch01.txt

rsr_convert_scripts/ghi_rsr.py

@@ -0,0 +1,112 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# Copyright (c) 2018-2023 Pytroll developers
+#
+#
+# This program 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.
+#
+# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Read the FY-4B GHI relative spectral responses.
+
+Data from https://img.nsmc.org.cn/PORTAL/NSMC/DATASERVICE/SRF/FY4B/FY4B_GHI_SRF.zip
+"""
+import os
+
+import numpy as np
+
+from pyspectral.raw_reader import InstrumentRSR
+from pyspectral.utils import INSTRUMENTS
+from pyspectral.utils import convert2hdf5 as tohdf5
+from pyspectral.utils import get_logger, logging_on
+
+FY4_GHI_BAND_NAMES = ['ch1', 'ch2', 'ch3', 'ch4', 'ch5', 'ch6', 'ch7']
+BANDNAME_SCALE2MICROMETERS = {'FY-4B': {'ch1': 0.001,
+                                        'ch2': 0.001,
+                                        'ch3': 0.001,
+                                        'ch4': 0.001,
+                                        'ch5': 0.001,
+                                        'ch6': 0.001,
+                                        'ch7': 1.0,
+                                        }}
+
+
+class GHIRSR(InstrumentRSR):
+    """Container for the FY-4 GHI RSR data."""
+
+    def __init__(self, bandname, platform_name):
+        """Initialise the FY-4 GHI relative spectral response data."""
+        super(GHIRSR, self).__init__(bandname, platform_name, FY4_GHI_BAND_NAMES)
+
+        self.instrument = INSTRUMENTS.get(platform_name, 'ghi')
+        if type(self.instrument) is list:
+            self.instrument = 'ghi'
+
+        self._get_options_from_config()
+        self._get_bandfilenames()
+
+        LOG.debug("Filenames: %s", str(self.filenames))
+        if self.filenames[bandname] and os.path.exists(self.filenames[bandname]):
+            self.requested_band_filename = self.filenames[bandname]
+            scale = BANDNAME_SCALE2MICROMETERS[platform_name].get(bandname)
+            if scale:
+                self._load(scale=scale)
+            else:
+                LOG.error(
+                    "Failed determine the scale used to convert to wavelength in micrometers - channel = %s", bandname)
+                raise AttributeError('no scale for bandname %s', bandname)
+
+        else:
+            LOG.warning("Couldn't find an existing file for this band: %s",
+                        str(self.bandname))
+
+        self.filename = self.requested_band_filename
+
+    def _load(self, scale=0.001):
+        """Load the GHI RSR data for the band requested.
+
+        Wavelength is given in nanometers.
+        """
+        data = np.genfromtxt(self.requested_band_filename,
+                             unpack=True, delimiter='\t',
+                             names=['wavelength',
+                                    'response'],
+                             skip_header=1)
+
+        wavelength = data[0] * scale
+        response = data[1]
+
+        # Response can be either 0-1 or 0-100 depending on RSR source - this scales to 0-1 range.
+        if np.nanmax(response > 1):
+            response = response / 100.
+
+        # Cut unneeded points
+        pts = np.argwhere(response > 0.001)
+
+        wavelength = np.squeeze(wavelength[pts])
+        response = np.squeeze(response[pts])
+
+        self.rsr = {'wavelength': wavelength, 'response': response}
+
+
+def convert_ghi():
+    """Read original GHI RSR data and convert to common Pyspectral hdf5 format."""
+    # For FY-4B
+    tohdf5(GHIRSR, 'FY-4B', FY4_GHI_BAND_NAMES)
+
+
+if __name__ == "__main__":
+    LOG = get_logger(__name__)
+    logging_on()
+
+    convert_ghi()