GRIB 格式

reki.format.grib.eccodes.load_field_from_file(file_path: str | Path, parameter: str | Dict = None, level_type: str | Dict = None, level: int | float | List | Dict | str = None, level_dim: str | None = None, field_name: str | None = None, show_progress: bool = False, **kwargs) → DataArray | None

Load one field from local GRIB2 file using eccodes-python. Or load multi levels into one field.

参数:

• file_path (str or Path)

• parameter (str or Dict) --

  parameter name.

  Use GRIB key shortName or a dict of filter conditions such as:

  {
      "discipline": 0,
      "parameterCategory": 2,
      "parameterNumber": 225,
  }
  

• level_type (str or Dict or None) --

  level type.

  • Use "pl", "ml" or "sfc". They will be converted into dict.

  • Use GRIB key typeOfLevel, such as

    • "isobaricInhPa"

    • "isobaricInPa"

    • "surface"

    • "heightAboveGround"

    • "nominalTop"

    • "atmosphere"

    • "meanSea"

    • "depthBelowLandLayer"

    • ...

    See https://apps.ecmwf.int/codes/grib/format/edition-independent/3/ for more values.

  • If typeOfLevel is not available, use dict to specify filter conditions. For example, to get one filed from GRAPES GFS modelvar GRIB2 file, use:

    {
        "typeOfFirstFixedSurface": 131
    }
    

• level (int or float or List or Dict or None) --

  level value(s).

  • If use a scalar, level will be a non-dimension coordinate.

  • If your want to extract multi levels, use a list and level will be a dimension (level, lat, lon).

  • If use a dict, message will be filtered by dict keys. Support custom calculate keys:

    • first_level

    • second_level

  • If use "all", all levels of level_type will be packed in the result field.

  • If use None, only the first field will be returned.

• level_dim (str or None) --

  name of level dimension. If none, function will generate a name for level dim. If level_type="pl", some values can be used:

  • None or pl or isobaricInhPa: level_dim is a float number with unit hPa.

  • isobaricInPa: level_dim is a float number with unit Pa.

• field_name --

  name of field.

  • If None, generate field name automatically.

    • use parameter if it's a string

    • use GRIB Key shortName if it's not unknown

    • use GRIB Keys to combine a name: discipline_parameterCategory_parameterNumber

  • If string, set the field's name with it.

• show_progress (bool) -- show progress bar.

返回:

DataArray if found, or None if not.

返回类型:

DataArray or None

示例

Load 850hPa temperature field from a GRIB2 file generated by GRAPES GFS.

>>> load_field_from_file(
...     file_path="/sstorage1/COMMONDATA/OPER/NWPC/GRAPES_GFS_GMF/Prod-grib/2020031721/ORIG/gmf.gra.2020031800105.grb2",
...     parameter="t",
...     level_type="isobaricInhPa",
...     level=850,
... )
<xarray.DataArray 't' (latitude: 720, longitude: 1440)>
array([[249.19234375, 249.16234375, 249.16234375, ..., 249.15234375,
        249.19234375, 249.14234375],
       [249.45234375, 249.45234375, 249.42234375, ..., 249.45234375,
        249.44234375, 249.44234375],
       [249.69234375, 249.68234375, 249.68234375, ..., 249.70234375,
        249.67234375, 249.68234375],
       ...,
       [235.33234375, 235.45234375, 235.62234375, ..., 235.47234375,
        235.63234375, 235.48234375],
       [235.78234375, 235.91234375, 235.64234375, ..., 235.80234375,
        235.72234375, 235.82234375],
       [235.66234375, 235.86234375, 235.82234375, ..., 235.85234375,
        235.68234375, 235.70234375]])
Coordinates:
    time           datetime64[ns] 2020-03-18
    step           timedelta64[ns] 4 days 09:00:00
    valid_time     datetime64[ns] 2020-03-22T09:00:00
    isobaricInhPa  int64 850
  * latitude       (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88
  * longitude      (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8
Attributes:
    GRIB_edition:                    2
    GRIB_centre:                     babj
    GRIB_subCentre:                  0
    GRIB_tablesVersion:              4
    GRIB_localTablesVersion:         1
    GRIB_dataType:                   fc
    GRIB_dataDate:                   20200318
    GRIB_dataTime:                   0
    GRIB_validityDate:               20200322
    GRIB_validityTime:               900
    GRIB_step:                       105
    GRIB_stepType:                   instant
    GRIB_stepUnits:                  1
    GRIB_stepRange:                  105
    GRIB_endStep:                    105
    GRIB_name:                       Temperature
    GRIB_shortName:                  t
    GRIB_cfName:                     air_temperature
    GRIB_discipline:                 0
    GRIB_parameterCategory:          0
    GRIB_parameterNumber:            0
    GRIB_gridType:                   regular_ll
    GRIB_gridDefinitionDescription:  Latitude/longitude
    GRIB_typeOfFirstFixedSurface:    pl
    GRIB_typeOfLevel:                isobaricInhPa
    GRIB_level:                      850
    GRIB_numberOfPoints:             1036800
    GRIB_missingValue:               9999
    GRIB_units:                      K
    long_name:                       Temperature
    units:                           K