Questions Regarding WRF-Hydro 5.4.0 Standalone Version and Output Analysis

[msvramana]

Dear Users,

I hope this message finds you well.

I have recently installed the WRF-Hydro Standalone version 5.4.0 successfully and completed the test case over the Croton, New York domain, following the instructions provided in the official test case documentation and user manual. The model ran successfully without errors.

However, after running the test case, I was unable to locate the surface runoff variable in any of the output files. To further analyze the outputs, I attempted to use Python for reading and visualizing the data. During this process, I encountered some challenges, such as:

• Converting UTM coordinates to geographic coordinates,

• Plotting inundation maps and other variables properly.

I would appreciate your support with the following questions:

1. How can I obtain the surface runoff variable? Is there a specific option in the namelist or another relevant output variable that represents it?

2. Are there any free tools or plugins (e.g., for ArcGIS, QGIS, or Python) recommended for working with WRF-Hydro 5.4.0 output data?

3. Is there a comprehensive user manual or guide for the Standalone WRF-Hydro model, similar to what is available for WRF atmospheric modeling?

Additionally, could you kindly let me know:

• Is there a standard procedure or tool for post-processing and visualization of WRF-Hydro output data?

• Are there any recommended tutorials or example workflows for Python-based analysis of WRF-Hydro results?

Thank you in advance for your guidance and support.

Regards,

MSV

[aubrey]

Hi MSV:

Whether or not you get an output variable for surface runoff depends on your physics configuration and what you are *really* interested in when you say "surface runoff". If you are running a configuration without overland routing active, you will see the land surface model's conceptual "SFCRNOFF" variable in the LDASOUT land model output files. If you are running a configuration with overland routing enabled, WRF-Hydro will explicitly route the land model's excess surface water, so it can become "sfcheadsubrt" in the RTOUT file (ponded water on the surface on the high-res grid) or "qSfcLatRnoff" in the CHRTOUT file (overland flow that flows into a channel cell/reach). So what variable you want to use really depends on your particular application and the process you are interested in.

Our training materials show examples of how to work with WRF-Hydro outputs using Python:

https://github.com/NCAR/wrf_hydro_training/tree/main/lessons/training

We also have a comprehensive user guide:

https://wrf-hydro.readthedocs.io/en/latest/index.html

I believe our gridded outputs should work with standard geospatial applications if you are using a spatial metadata file, but I don't normally use these applications so can't say for sure these all work seamlessly.

Hope that helps.

Thanks!

Aubrey