绘制时间-高度剖面图报错

怪力金鱼姬

初学小白想绘制相对湿度的时间-高度剖面，这个错误不知道该如何处理，求助各位大佬~
代码：
import xarray as xr
import numpy as np
import datetime as dt
import cartopy.crs as ccrs
import cartopy.feature as cfeature
import cartopy.mpl.ticker as cticker
import matplotlib.pyplot as plt
import matplotlib.ticker as ticker
from decimal import Decimal
plt.rcParams['font.sans-serif']=['SimHei']
plt.rcParams['axes.unicode_minus']=False

ds=xr.open_dataset(r'F:\20200525.nc')
r=ds.r.loc['2020-05-24 20:00':'2020-05-26 20:00',:,27,98]
r = np.array(r).reshape((17,16))
time=ds.variables['time'][38:55]
level=ds.variables['level'][:]
lat=ds['latitude']
lon=ds['longitude']

fig = plt.figure(figsize=(9,6))
ax = fig.add_axes([0.1, 0.1, 0.8, 0.6])
ax.set_yscale('symlog')
ax.set_yticks([700,500,300,200,100])
ax.set_yticklabels(['700','500','300','200','100'])
ax.invert_yaxis()
ax.set_ylabel('Level (hPa)',fontsize=18)
ax.set_xlabel('time',fontsize=18)
c = ax.contourf(time,level,r.T,level=np.arange(0,100,10),extend = 'both',zorder=0, cmap=plt.cm.bwr)
position=fig.add_axes([0.65, 0.034, 0.3, 0.017])
fig.colorbar(c,cax=position,orientation='horizontal',format='%d',)
报错信息：OverflowError: int too big to convert