python读取nc文件并绘制全球年平均气温折线图

wudi129

1. import numpy as np
   
2. import matplotlib.pyplot as plt
   
3. import netCDF4 as nc
   
4. from netCDF4 import num2date
   
5. import pandas as pd
   
6. import datetime
   
7. 
   
8. file = 'F:/data/HadCRUT.nc'
   
9. data = nc.Dataset(file)
   
10. lat = np.array(data.variables['latitude'])
    
11. lon = np.array(data.variables['longitude'])
    
12. t = np.array(data.variables['time'])
    
13. tas_mean = np.array(data.variables['tas_mean'])
    
14. tas_mean[tas_mean == -1.e+30] = np.nan
    
15. 
    
16. def cftime2datetime(cftime, units, format='%Y-%m-%d %H:%M:%S'):
    
17.     """
    
18.     将nc文件里面的时间格式 从cftime 转换到 datetime格式
    
19.     :param cftime:
    
20.     :param units:
    
21.     :param format:
    
22.     :return:
    
23.     """
    
24.     return datetime.datetime.strptime(num2date(times=cftime, units=units).strftime(format), format)
    
25. 
    
26. 
    
27. clean_time_data = pd.Series([cftime2datetime(i, units='days since 1850-01-01 00:00:00') for i in t])
    
28. 
    
29. def y_m(year):
    
30.     v = np.nanmean(tas_mean[clean_time_data.dt.year == year,:,:].flatten())
    
31.     return v
    
32. 
    
33. year = np.arange(start = 1979,stop = np.max(clean_time_data.dt.year) + 1)
    
34. 
    
35. need = pd.DataFrame({'year': year})
    
36. need['tas_mean'] = need['year'].apply(lambda x: y_m(year = x))
    
37. 
    
38. 
    
39. fig , ax = plt.subplots(figsize = (10,4),dpi = 150)
    
40. ax.plot(need['year'],need['tas_mean'],linestyle = '-',marker = 'o')
    
41. plt.show()

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吃南瓜的wn

您好，这是在哈德来下载的海温么，我在网上下载的是datatime64格式的，但是想学习一下怎样转换cftime格式的时间