Satellite Radiance DA prepare initial satbias files and others

If one wants to do satellite radiance DA, one must prepare the initial satbias files correctly based on the experiment setup.

The initial satbias files may be copied from previous RRFS.v2 runs (retrospective, realtime, or operational runs).
If none of the above is available, rrfs-workflow will use the staged satbias files under ${FIXrrfs}/satbias_init.

To prepare the initial satbias files, one will need to run the following commands before running the ROCOTO workflow.

cd ${expdir}
source qrocoto/load_qrocoto.sh
prep_satbias.sh  YYYYMMDDHH  [satbias_path]

1. How to determine the above YYYYMMDDHH parameter for retros?

(1). Generally, YYYYMMDDHH is the cycle before the first DA cycle of a retro.

The first DA cycle will be different depending on whether we have spinup cycles.

Example:
a. A retro starts at 2024050600 without spinup cycles, then the first DA cycle is 2024050600 and we will use 2024050523 when running prep_satbias.sh.
b. A retro starts at 2024050600 with spinup cycles starting at 03/15z, then the first DA cycle will be 2024050603 and we will use 2024050602 when running prep_satbias.sh.

(2). What about COLDSTART_CYCS_DO_DA=false?

If we don't do DA at the cold start cycles, we will need to run prep_statbias.sh twice for the two cycles before the first DA cycle.
This is to jumpstart the first jedivar task, which, although does not update the background, has a dependency on the satbias_jumpstart file.

Example:
a. A retro starts at 2024050600 without spinup cycles and without coldstart DA, then the first DA cycle is 2024050601 and we will run the following commands:

prep_satbias.sh 2024050600
prep_satbias.sh 2024050523

b. A retro starts at 2024050600 with spinup cycles starting at 03/15z and without coldstart DA, then the first DA cycle will be 2024050604 and we will run the following commands:

prep_satbias.sh 2024050603
prep_satbias.sh 2024050602

(3). What about real-time runs?

Real-time runs can look back 5 cycles to find satbias files. So, real-time POCs only need to make sure there are satbias files available in the past 5 cycles.
In the situation where we bump the version number of rrfs-workflow or rrfs-workflow stops for more than 5 hours, real-time POCs can utilize the prep_satbias.sh tool as well.

2. How to determine the above [satbias_path] parameter for retros?

This parameter is optional. If it is missing, prep_satbias.sh will copy staged satbias files from ${FIXrrfs}/satbias_init One can put satbias files in any locations as long as it is accessible by the prep_satbias.sh command