xarray.merge：ValueError：找不到任何维度坐标来用于排序数据集以进行串联

Question

我想将多个 .nc 文件合并为一个。每个 .nc 文件都对应一个时间步长，应将其添加到一起以形成一个包含所有日期的所有数据的 .nc 文件。

当我执行以下行时，我会收到错误消息，尽管有几个维度可用（时间、纬度、经度），但未找到维度。为什么它不起作用？

代码：

ds = xr.open_mfdataset(os.getcwd() + '/test/*.nc')

Traceback：

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-40-c0e9d8bf97e7> in <module>
----> 1 ds = xr.open_mfdataset(os.getcwd() + '/test/*.nc')

/opt/conda/lib/python3.7/site-packages/xarray/backends/api.py in open_mfdataset(paths, chunks, concat_dim, compat, preprocess, engine, data_vars, coords, combine, parallel, join, attrs_file, combine_attrs, **kwargs)
    945                 coords=coords,
    946                 join=join,
--> 947                 combine_attrs=combine_attrs,
    948             )
    949         else:

/opt/conda/lib/python3.7/site-packages/xarray/core/combine.py in combine_by_coords(data_objects, compat, data_vars, coords, fill_value, join, combine_attrs, datasets)
    903                 compat=compat,
    904                 join=join,
--> 905                 combine_attrs=combine_attrs,
    906             )
    907             concatenated_grouped_by_data_vars.append(concatenated)

/opt/conda/lib/python3.7/site-packages/xarray/core/combine.py in _combine_single_variable_hypercube(datasets, fill_value, data_vars, coords, compat, join, combine_attrs)
    602         )
    603 
--> 604     combined_ids, concat_dims = _infer_concat_order_from_coords(list(datasets))
    605 
    606     if fill_value is None:

/opt/conda/lib/python3.7/site-packages/xarray/core/combine.py in _infer_concat_order_from_coords(datasets)
    128     if len(datasets) > 1 and not concat_dims:
    129         raise ValueError(
--> 130             "Could not find any dimension coordinates to use to "
    131             "order the datasets for concatenation"
    132         )

ValueError: Could not find any dimension coordinates to use to order the datasets for concatenation

我想要合并的 .nc 文件之一的示例（全部相同）：

<xarray.Dataset>
Dimensions:                  (columns: 321, rows: 321, Time: 1)
Coordinates:
    longitude                (columns, rows) float32 ...
    latitude                 (columns, rows) float32 ...
    time                     (Time) datetime64[ns] 2010-01-02T02:00:00
Dimensions without coordinates: columns, rows, Time
Data variables:
    cdr_surface_albedo       (Time, columns, rows) float32 ...
    cdr_surface_temperature  (Time, columns, rows) float32 ...
Attributes:
    standard_name:          surface_albedo
    long_name:              NOAA CDR of surface broadband albedo
    valid_range:            [0. 1.]
    units:                  1
    grid_mapping:           crs
    coverage_content_type:  physicalMeasurement

Answer 1

您可以尝试 NCO 的 ncrcat：

ncrcat in*.nc out.nc