Model Spinup

[Kayla Yamamoto]

I had a quick question about the WRF-Hydro spin-up process that I was hoping someone could help me with.

Does the model spin-up need to be redone for every modification you make to the domain (size/resolution), model physics options, etc.?

Are there any cases where you wouldn't need to redo the spin-up, and could just reuse the restart files generated from a previous spin up period?

Any information is greatly appreciated!

Thanks,

Kayla

[Donny Kim]

Hi,

My knowledge on WRF-Hydro is limited, however, I will share my general experience and I am open to any comments.

1. Change in domain size or resolution= need to redo spin-up(s), unless you manually resample/modify those restart files to match new domain (which is impractical).

2. Physics options = It depends on which option you are changing. In many cases, model itself will run using restart files that were generated from previous spin-up(s) that has minor difference in physics option. However, when doing so, WRF-Hydro may take some time stabilizing soil/gw/snow/etc storage, and model simulation may not yield the most reliable results in those early periods.

I hope it helps.

Best,

Donny

[Kayla Yamamoto]

Hi Donny,

Super helpful insight! Thank you so much for sharing!

For physics options, I'm testing some of the Noah-MP LSM groundwater/baseflow options (e.g. free drainage, MMF groundwater, etc.), so it'll be important for me to redo the spin up and let the model stabilize before I attribute any changes in model output to their associated physics options.

I'm new to hydrological modeling, so I appreciate you sharing your input!

Thanks again,

Kayla