I am currently using MPAS-JEDI to perform 3DVar data assimilation for a regional forecast, but I am unable to find suitable static BE (background error covariance) files for my domain（15km， 1000km radius domain）. The tutorial doesn’t seem to provide instructions for generating background error covariance by myself, and my current computing resources cannot support using ensemble forecasting。
I noticed that the NMC method can be used to generate BE files, but I’m curious whether mpasjedi_error_covariance_toolbox.x supports using regional forecast outputs as input. Additionally,I got fatal error without log*.err file when I run BJ’ programs using regional f48-f24 result cutting from global domain. there seems to be an issue with computing stream functions in regional configurations？
I also noticed some researchers use interpolation methods to downscale coarse-resolution BE (e.g., 60km) to their regional domains. I’d like to seek assistance on this approach.
Thank you for your interest in MPAS-JEDI. We have a limited resource for user support, especially this B training part. However, we are preparing the hands-on practice and some documentation to generate the static background error statistics in upcoming tutorial in June 2025. The materials and test dataset should be available to generic users after the event.
For your question, mpasjedi_error_covariance_toolbox.x can handle the regional forecast outputs as an input. In this case, however, it can only estimate the univariate B (without cross variable covariance).
Or did you first convert the zonal/meridional winds to stream function and velocity potential in the global mesh, then interpolate (or cut) to your regional mesh ? I have not tried this before, but in principal this will work.
Yes, we can interpolate the B statistics into different horizontal mesh (even regional). We may include this part in the tutorial.
Hi there, How to generate global BE matrix for a variable 60-15-km domain? I used to run all test runs, but now I wanted to create a good BE for my 60-15-km variable mesh. Thanks, Minghua