3.4. solver¶
Parameters for the core LETKF solver, diagnostic output, and covariance inflation.
Parameters
save_diag: | type: boolean, default: true Whether a diagnostic file is saved at the end of the UMD-LETKF run. This file contains diagnostic information such as the number of observations used per grid cell, maximum horizontal localization radius, etc. See LETKF Solver Diagnostics |
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diag_file: | type: string, default: “diag.solver.nc” The file name of the diagnostic output. Only used if |
Example
solver:
save_diag: true
diag_file: "diag.solver.nc"
3.4.1. inflation¶
Covariance inflation methods for increasing the ensemble spread. This section is optional. If not provided the default of “no inflation” will be used.
Note
The RTPS and RTPP methods cannot be enabled simultaneously.
Parameters
mul: | type: float, default: 1.0 The amount of Multiplicative inflation to apply. Valid parameters are greater than or equal to 1.0. Value of 1.0 indicates multiplicative inflation is off. |
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rtpp: | type: float, default: 0.0 The percentage of Relaxation to Prior Perturbations (RTPP) to apply. Valid parameters are between 0.0 and 1.0. Value of 0.0 indicates RTPS is off, 1.0 indicates the analysis ensemble perturbations are relaxed 100% back toward the background perturbation. Unless you know what you are doing, you are better off using Relaxation to Prior Spread (RTPS). Cannot be used if RTPS is enabled |
rtps: | type: float, default: 0.0 The percentage of Relaxation to Prior Spread (RTPS) to apply. Valid parameters are between 0.0 and 1.0. A value of 0.0 indicates RTPS is off, 1.0 indicates analysis spread is relaxed 100% back toward the background spread. Values between 0.5 and 0.8 are often good choices. You could in theory use values greater than 1.0 to result in analysis spread that is larger than background spread, but I have no idea why you would want to do this. Cannot be used if RTPP is enabled. |
Example
solver:
inflation:
rtps: 0.6
rtpp: 0.0
mul: 1.0