coordinated universal time (utc) meaning in English

世界标准时间
协调世界时

This function retrieves the current system date and time . the system time is expressed in coordinated universal time ( utc )
请问本地日期时间和系统日期时间有什么区别？谢谢！
It will remain in operation until 3 . 30 pm today to oversee the coordinated universal time ( utc ) rollover at 8 am
该中心将运作至今日下午三时三十分，以便监察上午八时国际标准时间过渡情况。