satpy.readers.eum_l2_grib module

Reader for both SEVIRI and FCI L2 products in GRIB2 format.

References

FM 92 GRIB Edition 2 https://www.wmo.int/pages/prog/www/WMOCodes/Guides/GRIB/GRIB2_062006.pdf EUMETSAT Product Navigator https://navigator.eumetsat.int/

class satpy.readers.eum_l2_grib.EUML2GribFileHandler(filename, filename_info, filetype_info)[source]

Bases: BaseFileHandler

Reader class for EUM L2 products in GRIB format.

Read the global attributes and prepare for dataset reading.

_get_attributes()[source]

Create a dictionary of attributes to be added to the dataset.

Returns:

A dictionary of parameter attributes.: ssp_lon: longitude of subsatellite point sensor: name of sensor platform_name: name of the platform

Return type:

dict

static _get_from_msg(gid, key)[source]

Get a value from the GRIB message based on the key, return None if missing.

Parameters:

gid – The ID of the GRIB message.
key – The key of the required attribute.

Returns:

The retrieved attribute or None if the key is missing.

_get_proj_area(gid)[source]

Compute the dictionary with the projection and area definition from a GRIB message.

Parameters:

gid – The ID of the GRIB message.

Returns:

A tuple of two dictionaries for the projection and the area definition.

pdict:: a: Earth major axis [m] b: Earth minor axis [m] h: Height over surface [m] ssp_lon: longitude of subsatellite point [deg] nlines: number of lines ncols: number of columns a_name: name of the area a_desc: description of the area p_id: id of the projection
area_dict:: center_point: coordinate of the center point north: coodinate of the north limit east: coodinate of the east limit west: coodinate of the west limit south: coodinate of the south limit

Return type:

tuple

_get_xarray_from_msg(gid)[source]

Read the values from the GRIB message and return a DataArray object.

Parameters:: gid – The ID of the GRIB message.
Returns:: The array containing the retrieved values.
Return type:: DataArray

_read_attributes(gid)[source]: Read the parameter attributes from the message and create the projection and area dictionaries.

static _scale_earth_axis(data)[source]

Scale Earth axis data to make sure the value matched the expected unit [m].

The earthMinorAxis value stored in the MPEF aerosol over sea product prior to December 12, 2022 has the wrong unit and this method provides a flexible work-around by making sure that all earth axis values are scaled such that they are on the order of millions of meters as expected by the reader.

calculate_area_extent = None

property end_time: Return the sensing end time.

get_area_def(dataset_id)[source]: Return the area definition for a dataset.

get_dataset(dataset_id, dataset_info)[source]

Get dataset using the parameter_number key in dataset_info.

In a previous version of the reader, the attributes (nrows, ncols, ssp_lon) and projection information (pdict and area_dict) were computed while initializing the file handler. Also the code would break out from the While-loop below as soon as the correct parameter_number was found. This has now been revised becasue the reader would sometimes give corrupt information about the number of messages in the file and the dataset dimensions within a given message if the file was only partly read (not looping over all messages) in an earlier instance.

property start_time: Return the sensing start time.