Das script will need to be updated to handle ExtData2G

[bena-nasa]

@rtodling
This is a public service announcement based on expected changes coming to the model.

All the chemistry codes are in the process of transitioning to use the new version of ExtData which uses yaml files rather than rc file. This is just a heads up that the DAS scripting will undoubtedly need to be updated to handle this. But is gets less complicated not more!

For now both versions (the rc and yaml files) exists for testing (ExtData2G itself is turned on by a flag in the CAP.rc but when all testing is complete ExtData2G will become the default.

The main pertinent change for the DAS scripting is

1. All the magic date logic can go away, no more of this awful, if date is less than so and so copy set of files and if after use this set. Rather once these emissions set is identified there is just one set of yaml files that are NOT date dependent, unlike the old ExtData.
2. Once the proper yaml files are copied (and once again this is NOT date dependent). There is a little script that gets run that examines the GEOS_ChemGridComp.rc and constructs the main extdata.yaml file based on what is actually turned on. So the DAS scripting will need to run this before executing the model:

$GEOSBIN/construct_extdata_yaml_list.py GEOS_ChemGridComp.rc

and that should be it, much simper really, no more magic dates.