I am trying to use the GLDAS 2.1 3-hourly precipitation datasets available at:
The dataset is documented here: https://hydro1.gesdisc.eosdis.nasa.gov/data/GLDAS/README_GLDAS2.pdf
The data is available as NetCDF4 files, one file per time-step, for example:
GLDAS_NOAH025_3H.A20180208.0600.021.nc4 GLDAS_NOAH025_3H.A20180208.0900.021.nc4 GLDAS_NOAH025_3H.A20180208.1200.021.nc4
where 3H means 3-hour time step, A20180208 means the date 8th February 2018, 0600 means the time 6:00 UTC, 021 means the product version. The NetCDF file contains a variable Rainf_f_tavg (Total precipitation rate) in units kg m-2 s-1.
What is not clear to me from the documentation is how to interpret the precipitation rate:
- Is this the average precipitation rate between 6:00 UTC and 9:00 UTC?
- or is this the average precipitation rate between 3:00 UTC and 6:00 UTC?
- or is this the averate precipitation rate between 4:30 UTC and 7:30 UTC?
This information is critical for me if I want to correctly calculate accumulated precipitation for example how much rain+snow in mm has fallen between 7th February 2018 6:00 UTC and 8th February 2018 6:00 UTC.