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我正在尝试使用xarray和从 DWD 的 ICON 模型加载 GRIB2 文件cfgrib。大多数变量都可以正常工作,但对于某些变量(例如CLCL),xarray.open_dataset会引发以下错误:

Traceback (most recent call last):
  File "/shared/conda/envs/devtools/lib/python3.8/site-packages/xarray/core/dataset.py", line 1398, in _construct_dataarray
    variable = self._variables[name]
KeyError: 'CLCL'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "DAT-2634/grib_file_loaders.py", line 276, in <module>
    df_cfgrib_sf = read_cfgrib_sf(grib_fns, nodes, params)
  File "DAT-2634/grib_file_loaders.py", line 115, in read_cfgrib_sf
    x = xr.open_dataset(
  File "/shared/conda/envs/devtools/lib/python3.8/site-packages/xarray/core/dataset.py", line 1502, in __getitem__
    return self._construct_dataarray(key)
  File "/shared/conda/envs/devtools/lib/python3.8/site-packages/xarray/core/dataset.py", line 1400, in _construct_dataarray
    _, name, variable = _get_virtual_variable(
  File "/shared/conda/envs/devtools/lib/python3.8/site-packages/xarray/core/dataset.py", line 173, in _get_virtual_variable
    ref_var = variables[ref_name]
KeyError: 'CLCL'

grib_ls当我通过我检查文件时

$ grib_ls ICON_europe_reg_0.125x0.125_2021101900_f000.grib2 | grep CLCL
2            edzw         20211019     fc           regular_ll   0            unknown      800          CLCL         grid_simple 

我在cfgrib问题#195#213中读到这可能是由于使用了本地代码,并且我可能能够使用适当的代码表来解决问题。DWD 确实为 ecCodes 提供了 GRIB 表,但我不确定如何将它们与cfgrib.

如何使用自定义代码表cfgrib?还是有另一种方法来加载这些变量?

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1 回答 1

0

在没有进一步了解之后,我cfgribGitHub 项目中发布了与问题相同的问题,并在那里得到了回复:解决方案是将自定义代码表的路径添加到ECCODES_DEFINITION_PATH环境变量中:

import os
from pathlib import Path
import xarray

ECCODES_DEFINITION_PATHS = [
    # The custom codes I want to use
    Path('path/to/the/custom/codes'),

    # The codes from my system's ecCodes installation
    Path('/usr/share/eccodes/definitions'),
]
os.environ['ECCODES_DEFINITION_PATH'] = ':'.join(
    str(p.resolve())
    for p in ECCODES_DEFINITION_PATHS
)

x = xarray.open_dataset(...)

ECMWF wiki 中有详细的文档。

于 2021-11-19T13:41:41.133 回答