NetCDF Requirements
Vortex reads the interval a grid applies over from the NetCDF file itself. When it cannot, it says so rather than guessing.
If you import a NetCDF file without a time_bnds variable, Vortex warns you and asks whether to continue:
CF compliance check failed: One or more NetCDF datasets do not contain a "time_bnds" variable. Imported start/end times may be inaccurate. Use the time-shifter utility to shift start and/or end times after import.
Do you want to proceed?
time_bnds defines the interval over which the data applies. Without it Vortex does not make any guesses about what that interval might be, so the import proceeds using the time stamps it does have, and those may not line up with the period the data actually represents.
Answering yes imports the data. Correcting the times is a second step, so processing a file like this takes two utilities:
- Use the importer utility to import the data to HEC-DSS.
- Use the time-shifter utility to shift the start time and/or end time of the HEC-DSS grids by some amount, for example shifting the start time by -1 hours.
To recap, you must use two utilities for this import: the importer and the time-shifter.
Where non-CF compliant NetCDF files have been published, we recommend contacting the author of the data and asking them to include a time_bnds variable, to be more explicit about the data interval.