These keywords are used to specify the chronological characteristics of fields and observations.
- anoffset - keyword in MARS/Dissemination request
- date - keyword in MARS/Dissemination request
- fcmonth - keyword in MARS/Dissemination request
- fcperiod - keyword in MARS/Dissemination request
- hdate - keyword in MARS/Dissemination request
- range - keyword in MARS/Dissemination request
- refdate - keyword in MARS/Dissemination request
- reference - keyword in MARS/Dissemination request
- step - keyword in MARS/Dissemination request
- time - keyword in MARS/Dissemination request