python - 使用 Python 将变量添加到现有的 Netcdf4 文件

Question

我想向现有的 NetCDF 气候数据文件集添加一个包含儒略日期的附加变量。 我已经完成了一些 python 脚本，但是已经有一段时间了，所以我很生疏。阅读“netCDF4 模块”文档后，我尝试编写脚本以使用以下方法创建新变量:

newvarJD= infile.create.Variable('Julian_Day','i4',                                      
                                ('lon','lat','time'))# attributes, varname, 
                                                       dtype, dimensions=()
                                    

但是当它到达这一行时我得到一个“AttributeError: NetCDF: Attribute not found”:

文件“C:/WinPython64/WinPython-64bit-3.4.4.6Qt5/notebooks/netcfdfill.py”，第 35 行，在 newvarJD= infile.create.Variable('Julian_Day','i4',

所以，我认为需要声明尺寸，所以我更改了代码:

lat_nc = infile.dimensions['lat'] #define dimensions for create.variable
lon_nc = infile.dimensions['lon']
time_nc = infile.dimensions['time'] 

但现在我收到一个新错误，提示 KeyError: 'lat'

我把我对脚本的尝试包括在内，因为我想我还有几个错误。你能帮我吗？

#**************************
# Access standard libraries
#**************************
from netCDF4 import Dataset
import numpy as np
import os
# Set the input/output directories
wrkDir = 'C:/Netcfd/BCSD/test'
Minifile = wrkDir + '/tasmin'

#***************************
# Add a Julian date variable to all *.nc file in directory
#****************************


     
inList = os.listdir(Minifile)  # List all the files in the 'tasmin' 
                                 directory
print(inList)

for fileName in inList:     # Step through each file
    ifile = fileName
    baseName, extension = os.path.splitext(ifile)
    if extension == '.nc':
        infile = Dataset("ifile", "r+", format="NETCDF4")#append to add 
                                                          Julian
        lat_nc = infile.dimensions['lat'] #define dimensions for 
                                           create.variable
        lon_nc = infile.dimensions['lon']
        time_nc = infile.dimensions['time']
        newvarJD= infile.create.Variable('Julian_Day','i4',
                                        ('lon_nc','lat_nc','time_nc'))# 
                                                varname,dtype, dimensions=()
        newvarJD.units= "Days"
        newvarJD.long_name = 'Annual Julian Days'
    
        JD = 0 # counter used to set Julian day value
        for i in range(len(time_nc)):
           JD = JD + 1 # start with Julina Day 1
           newvarJD = np.asarray(infile[:,:,:,JD])# write data into the 
                                                    variable created
        print ('New NC dims ->'(infile.shape))
    infile.close()    
     

Answer 1

该函数称为 createVariable()。您的代码应该适用于该修复。