我有这个netcdf文件wrfout_d03.nc,其中我使用以下文件打开该文件:
ds = xr.open_dataset('/Users/jacob/Desktop/wrfpy/wrfout_d03_may.nc')
然后提供了一个DataSet对象:
<xarray.Dataset>
Dimensions: (Time: 193, bio_emissions_dimension_stag: 41, bottom_top: 50, bottom_top_stag: 51, klevs_for_dvel: 1, seed_dim_stag: 12, soil_layers_stag: 4, south_north: 115, south_north_stag: 116, west_east: 115, west_east_stag: 116)
Coordinates:
XLAT (Time, south_north, west_east) float32 ...
XLONG (Time, south_north, west_east) float32 ...
XTIME (Time) datetime64[ns] ...
XLAT_U (Time, south_north, west_east_stag) float32 ...
XLONG_U (Time, south_north, west_east_stag) float32 ...
XLAT_V (Time, south_north_stag, west_east) float32 ...
XLONG_V (Time, south_north_stag, west_east) float32 ...
Dimensions without coordinates: Time, bio_emissions_dimension_stag, bottom_top, bottom_top_stag, klevs_for_dvel, seed_dim_stag, soil_layers_stag, south_north, south_north_stag, west_east, west_east_stag
Data variables:
datavars...
然后我使用以下代码访问PM2_5_DRY变量:
pm25 = ds.PM2_5_DRY
结果对象pm25的尺寸和坐标如下:
<xarray.DataArray 'PM2_5_DRY' (Time: 193, bottom_top: 50, south_north: 115, west_east: 115)>
[127621250 values with dtype=float32]
Coordinates:
XLAT (Time, south_north, west_east) float32 ...
XLONG (Time, south_north, west_east) float32 ...
XTIME (Time) datetime64[ns] ...
Dimensions without coordinates: Time, bottom_top, south_north, west_east
Attributes:
FieldType: 104
MemoryOrder: XYZ
description: pm2.5 aerosol dry mass
units: ug m^-3
stagger:
然后,我操纵pm25对象,并通过以下方法获取time维度中的均值:
pm25_mean = pm25.mean(dim='Time', keep_attrs = True)
结果对象是一个DataArray,但没有坐标XLAT或XLON。
<xarray.DataArray 'PM2_5_DRY' (bottom_top: 50, south_north: 115, west_east: 115)>
array([[[14.73083 , 14.756626 , 14.796355 , ..., 20.325712 ,
20.855696 , 21.381271 ],
[14.651459 , 14.34477 , 14.371858 , ..., 18.00389 ,
18.4109 , 21.337002 ],
[14.59026 , 14.257076 , 14.293012 , ..., 17.391146 ,
18.217058 , 20.882664 ],
...,
[27.356459 , 27.21468 , 27.757051 , ..., 8.084272 ,
8.010168 , 7.989942 ],
[27.185486 , 27.02623 , 27.776043 , ..., 7.944748 ,
7.8795266 , 7.8552976 ],
[26.926008 , 27.724253 , 28.427626 , ..., 7.8269224 ,
7.773637 , 7.741844 ]],
Dimensions without coordinates: bottom_top, south_north, west_east
Attributes:
FieldType: 104
MemoryOrder: XYZ
description: pm2.5 aerosol dry mass
units: ug m^-3
stagger:
以下要检查的代码给出:
pm25_mean.coords
Coordinates:
*empty*
我尝试查看xarray中mean函数的文档;但是,我找不到任何将坐标从以前的对象复制到新对象的选项。
有关如何进行此操作的任何提示?我想我需要从文件访问这些坐标,然后再次将它们组合。但是我不确定如何执行此过程。
而且,这与此有关吗?
XLAT (Time, south_north, west_east) float32
XLAT是多维坐标,它也取决于时间。由于我获得了时间维度的均值,因此维度pm25的数量已减少至3,而不是4。这是否也可能会影响坐标?
我需要最终对象具有坐标,因为我将对此进行可视化。
感谢您的帮助!
我认为结果中仍然存在坐标XLAT和XLON。尝试pm25_mean.coords
进行检查。如果没有,您可以给我发送数据集链接吗?