Source code for satpy.readers.ascat_l2_soilmoisture_bufr

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright (c) 2021 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 <>.

"""ASCAT Soil moisture product reader for BUFR messages.

Based on the IASI L2 SO2 BUFR reader.


import datetime as dt
import logging

import dask.array as da
import numpy as np
import xarray as xr

    import eccodes as ec
except ImportError as e:
    raise ImportError(
        """Missing eccodes-python and/or eccodes C-library installation. Use conda to install eccodes.
           Error: """, e)

from satpy.readers.file_handlers import BaseFileHandler
from satpy.utils import get_legacy_chunk_size

logger = logging.getLogger("AscatSoilMoistureBufr")

CHUNK_SIZE = get_legacy_chunk_size()

[docs] class AscatSoilMoistureBufr(BaseFileHandler): """File handler for the ASCAT Soil Moisture BUFR product.""" def __init__(self, filename, filename_info, filetype_info, **kwargs): """Initialise the file handler for the ASCAT Soil Moisture BUFR data.""" super(AscatSoilMoistureBufr, self).__init__(filename, filename_info, filetype_info) start_time, end_time = self.get_start_end_date() self.metadata = {} self.metadata["start_time"] = start_time self.metadata["end_time"] = end_time @property def start_time(self): """Return the start time of data acqusition.""" return self.metadata["start_time"] @property def end_time(self): """Return the end time of data acquisition.""" return self.metadata["end_time"] @property def platform_name(self): """Return spacecraft name.""" return self.filename_info["platform"]
[docs] def extract_msg_date_extremes(self, bufr, date_min=None, date_max=None): """Extract the minimum and maximum dates from a single bufr message.""" ec.codes_set(bufr, "unpack", 1) size = ec.codes_get(bufr, "numberOfSubsets") years = np.resize(ec.codes_get_array(bufr, "year"), size) months = np.resize(ec.codes_get_array(bufr, "month"), size) days = np.resize(ec.codes_get_array(bufr, "day"), size) hours = np.resize(ec.codes_get_array(bufr, "hour"), size) minutes = np.resize(ec.codes_get_array(bufr, "minute"), size) seconds = np.resize(ec.codes_get_array(bufr, "second"), size) for year, month, day, hour, minute, second in zip(years, months, days, hours, minutes, seconds): time_stamp = dt.datetime(year, month, day, hour, minute, second) date_min = time_stamp if not date_min else min(date_min, time_stamp) date_max = time_stamp if not date_max else max(date_max, time_stamp) return date_min, date_max
[docs] def get_start_end_date(self): """Get the first and last date from the bufr file.""" with open(self.filename, "rb") as fh: date_min = None date_max = None while True: # get handle for message bufr = ec.codes_bufr_new_from_file(fh) if bufr is None: break date_min, date_max = self.extract_msg_date_extremes(bufr, date_min, date_max) return date_min, date_max
[docs] def get_bufr_data(self, key): """Get BUFR data by key.""" attr = np.array([]) with open(self.filename, "rb") as fh: while True: # get handle for message bufr = ec.codes_bufr_new_from_file(fh) if bufr is None: break ec.codes_set(bufr, "unpack", 1) tmp = ec.codes_get_array(bufr, key, float) if len(tmp) == 1: size = ec.codes_get(bufr, "numberOfSubsets") tmp = np.resize(tmp, size) attr = np.append(attr, tmp) ec.codes_release(bufr) return attr
[docs] def get_dataset(self, dataset_id, dataset_info): """Get dataset using the BUFR key in dataset_info.""" arr = self.get_bufr_data(dataset_info["key"]) if "fill_value" in dataset_info: arr[arr == dataset_info["fill_value"]] = np.nan arr = da.from_array(arr, chunks=CHUNK_SIZE) xarr = xr.DataArray(arr, dims=["y"], name=dataset_info["name"]) xarr.attrs["platform_name"] = self.platform_name xarr.attrs.update(dataset_info) return xarr