How to run multiple spatially discontinuous single sites within one CTSM case?

Fuhow

Fu Hao
Member
Hi,

I am currently working on calibrating CTSM using multiple observation sites. I have around 12 observation sites, and I would like to run these sites simultaneously within a single CTSM case rather than creating and compiling separate cases for each site. But there is no method for generating multiple mesh files with non-spatially contiguous grid points.

My understanding is that CTSM does not require the simulated grid cells to be spatially continuous, and a possible approach is to create a user-defined regional grid containing all observation sites as independent grid cells.

The workflow I am considering is:
  1. Create an ESMF grid file with 12 grid points, where each observation site corresponds to one grid cell, and assign the latitude and longitude of each observation site to the respective grid cell.
  2. subset 12 single point surface dataset from my regional surfdata by subset tool, combine these surfdata contain 12 grids at each observation.
  3. Create and run a simulation case using the combined 12-site mesh file and surfdata file. The site data can then be validated against the corresponding simulation output along the matching grid dimension.
My questions are:
  1. Is it possible and recommended to run multiple independent single-point sites as multiple grid cells within a single CTSM case?
  2. Is there an existing tool or script to generate an ESMF mesh/domain file for a collection of irregularly distributed sites?
  3. For this application, is it better to manually construct the mesh/domain files, or should I create multiple single-point cases and run them separately?
Thank you very much for your help and suggestions.
 

slevis

Moderator
Staff member
Yes, it is possible to do what you are considering. Same or similar approaches have been attempted successfully before. These approaches are advanced due to their complexity, and we do not support them with tools, scripts, or examples. However, you will find documentation from past attempts. These may be outdated but you should certainly look in these discussions:
and more specifically discussions including the word "sparse":

You may also find reference to sparse grids here in the Forums (I haven't searched to know for sure) and also in published papers, such as Kennedy et al. 2025 (https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024MS004715) and other similar studies.
 
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Fuhow

Fu Hao
Member
Yes, it is possible to do what you are considering. Same or similar approaches have been attempted successfully before. These approaches are advanced due to their complexity, and we do not support them with tools, scripts, or examples. However, you will find documentation from past attempts. These may be outdated but you should certainly look in these discussions:
and more specifically discussions including the word "sparse":

You may also find reference to sparse grids here in the Forums (I haven't searched to know for sure) and also in published papers, such as Kennedy et al. 2025 (https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024MS004715) and other similar studies.
Hi, @slevis

By comparing the simulation outputs from standalone single-point runs and combined sparse grid case runs, identical simulation results were obtained, which verifies the validity of this approach.

Thank you!
 
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