Confusion about HRLDAS forcing pre-processor

[cenlinhe]

Below is a question asked by a user through email:
"I found the following sentence in the README file from the HRLDAS repository at this link:
https://github.com/NCAR/hrldas/tree/master/hrldas

"I recommend downloading the forcing data with global coverage, since the current code only cope with global data array dimension."

Does this mean that the HRLDAS code itself is not adapted for regional simulations, or is it the forcing generation program that is not compatible with regional data? For my work, high-resolution simulations are essential, but I cannot afford the large storage requirements. Therefore, regional simulations are necessary for me. Can I use regional forcing data alongside the model? Will the HRLDAS system be able to handle this?
"

[cenlinhe]

The HRLDAS can also process regional simulation forcing data. The original meaning of that sentence is that, depending on what forcing data users use, the HRLDAS forcing will spatially interpolate the original global/regional forcing data into the regional domain/grids you provided in geo_em file. So the global data we recommend is the original dataset to be used for spatial interpolation into your regional grids.
You can certainly use original regional data instead of global data for spatial interpolation but currently HRLDAS only supports the spatial interpolation of GLDAS, NARR, NLDAS, and ERA5-Land forcing. If you use another forcing dataset, you will have to do the spatial interpolation using your own scripts.