nonstationary random process

例句：

1. 1. Theweather is nonstationary; it changesrapidly.
   天气不稳定，变化迅速。
2. 2. The systemis nonstationary; it will continueto evolve.
   系统是非静态的，将继续演变。
3. 3. The temperature is nonstationary; it fluctuates withthe season.
   温度是不稳定的，随着季节变化而波动。