卫星测高数据处理常见问题

1.时间转换

用matlab从jason-2的nc文件中读出的时间（time_20hz）单位，从数据说明中可以看出是以秒为单位，从2000-01-01 00:00:00.0开始：

time_20hz:
---------------------------
time field
[tai_utc_difference] is the difference between TAI and UTC reference time (seconds) for the first measurement of the data set. [leap_second] is the UTC time at which a leap second occurs in the data set,if any. After this UTC time,the [tai_utc_difference] is increased by 1 second

Dimensions:   time=3204     meas_ind=20   

- _FillValue: 18446744073709552000.000000
- calendar: gregorian
- leap_second: 0000-00-00 00:00:00
- standard_name: time
- tai_utc_difference: -33.000000
- units: seconds since 2000-01-01 00:00:00.0

如果要还原成日期怎么办？

简单的做法是，直接在excel中处理一下就可以了。