折线图并添加误差阴影

绘制降水的年际变化折线图，并添加误差范围，主要用到fill_between()函数，可以去matplotlib官网查看。
import matplotlib.pyplot as plt
import pandas as pd

cma = pd.read_excel(r'H:\Salween_result\2. spatialtemporal\CMA/1981-2018_CMA_annual_pre.xlsx', header=None,
                    names=['year', 'cma_pre'], skiprows=1)

 x, y = cma['year'], cma['cma_pre']

mstd = cma['cma_pre'].std()
y_up_err = y + mstd
y_low_err = y - mstd
fig, ax = plt.subplots()
ax.plot(x, y)
ax.fill_between(x, y_low_err, y_up_err, color='skyblue', alpha=0.2)
plt.show()