[wrf-hydro_users] Support Request about LDASIN & NUDGING for WRF-Hydro STANDALONE

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Fructueux EHOUINSOU

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Nov 19, 2025, 12:55:30 PM (3 days ago) Nov 19

to wrf-hyd...@ucar.edu

My name is Fructueux Ehouinsou, I am a Master’s student working on land–surface and hydrological modeling, and as part of my research work, I am implementing WRF-Hydro (standalone) over my study basin. I am reaching out for support regarding two important components of my WRF-Hydro standalone setup using the Noah LSM.

1. Generation of LDASIN Atmospheric Forcing Files

I am currently building LDASIN forcings from:

IMERG (30-min precipitation)
ERA5-Land (hourly meteorological variables)

However, I am facing challenges with:

correctly reprojecting IMERG/ERA5-Land to my model grid (projection from wrfinput_d01, Mercator)
ensuring full CF compliance (grid_mapping, scale_factor, esri_pe_string, etc.)
constructing fully valid LDASIN files (variable types/units, time & reference_time dimensions, RAINRATE generation)

I would appreciate guidance on:
→ recommended scripts, workflows, or examples for producing LDASIN forcings from IMERG + ERA5-Land datasets or other multiple data sources.

2. Configuration of Hydrologic Nudging

I also plan to activate discharge nudging for automatic calibration, but I am unsure how to:

correctly build the nudgingParams.nc file for my domain
generate the required NetCDF time-slice observation files from daily discharge data
handle the temporal mismatch (daily observations → hourly model timestep)
map streamflow gauge stations to the correct LINKID entries in RouteLink.nc

Any working examples (nudgingParams.nc, time-slice files, recommended workflow) would be extremely helpful.

Thank you very much for your support.
I can provide any required files (wrfinput, geo_em.dxx , RouteLink, generated LDASIN, etc.) if needed.