我正在使用虹吸管从Unidata Thredds服务器下载GFS数据，因此可以使用MetPy对其进行绘制。我写了一个脚本来做到这一点，并且昨天效果很好：
#Get data using siphon
best_gfs = TDSCatalog('http://thredds.ucar.edu/thredds/catalog/grib/NCEP/GFS/Global_0p25deg/catalog.xml?dataset=grib/NCEP/GFS/Global_0p25deg/Best')
best_ds = best_gfs.datasets[0]
ncss = best_ds.subset()
query = ncss.query()
query.lonlat_box(north=55,south=20,east=-60,west=-120).time(datetime.utcnow())
query.accept('netcdf4')
query.variables('Geopotential_height_isobaric')
data = ncss.get_data(query)
#Parse data using MetPy
ds = xr.open_dataset(NetCDF4DataStore(data))
data = ds.metpy.parse_cf()
time_of_run = data['reftime'][0].dt.strftime('%Y%m%d_%H%MZ').values
print(time_of_run)
当我在美国东部时间下午2点左右运行时，此代码输出了2020-03-29 12：00Z，一切都很好。
今天早上运行它时，出现错误：
Traceback (most recent call last):
File "C:\Users\jacks\Anaconda3\envs\metpy_test\lib\site-packages\xarray\core\dataset.py",line 1155,in _construct_dataarray
variable = self._variables[name]
KeyError: 'reftime'
During handling of the above exception,another exception occurred:
Traceback (most recent call last):
File "h5_rh_wind_gph_temp.py",line 51,in <module>
time_of_run = data['reftime'][0].dt.strftime('%Y%m%d_%H%MZ').values
File "C:\Users\jacks\Anaconda3\envs\metpy_test\lib\site-packages\xarray\core\dataset.py",line 1245,in __getitem__
return self._construct_dataarray(key)
File "C:\Users\jacks\Anaconda3\envs\metpy_test\lib\site-packages\xarray\core\dataset.py",line 1158,in _construct_dataarray
self._variables,name,self._level_coords,self.dims
File "C:\Users\jacks\Anaconda3\envs\metpy_test\lib\site-packages\xarray\core\dataset.py",line 165,in _get_virtual_variable
ref_var = variables[ref_name]
KeyError: 'reftime'
表示对“ reftime”键的引用无效。为了进行调查，我随后打印了“数据” xarray：
<xarray.Dataset>
Dimensions: (isobaric6: 34,lat: 141,lon: 241,time1: 1)
Coordinates:
reftime1 (time1) datetime64[ns] ...
* time1 (time1) datetime64[ns] 2020-03-30T12:00:00
* isobaric6 (isobaric6) float32 40.0 100.0 ... 100000.0
* lat (lat) float32 55.0 54.75 54.5 ... 20.25 20.0
* lon (lon) float32 240.0 240.25 ... 299.75 300.0
crs object Projection: latitude_longitude
Data variables:
Geopotential_height_isobaric (time1,isobaric6,lat,lon) float32 ...
LatLon_Projection int32 ...
Attributes:
Originating_or_generating_Center: ...
Originating_or_generating_Subcenter: ...
GRIB_table_version: ...
Type_of_generating_process: ...
Analysis_or_forecast_generating_process_identifier_defined_by_originating...
Conventions: ...
history: ...
featureType: ...
History: ...
geospatial_lat_min: ...
geospatial_lat_max: ...
geospatial_lon_min: ...
geospatial_lon_max: ...
表示我想要的信息（模型的运行时间）现在存储为“ reftime1”。为什么1突然出现在reftime键的末尾？它的出现有规律吗？我希望最终将这个脚本作为cron作业来运行，以自动生成图，因此，最好能找到一种方法来预期名称的更改或完全避开键名。