SatWindsLNVDCheck¶

This obsfunction follows a similar subroutine of GSI Observer to compute the log-normal vector difference (LNVD) between the observed and model winds. Calculation of LNVD uses the following $L N V D = \sqrt{(u_{o b} - u_{m o d e l})^{2} + (v_{o b} - v_{m o d e l})^{2}} / \log (observed wind speed)$ . Within GSI, computed values greater than a threshold (3.0) are used to reject winds, which can be accomplished using the Bounds Check filter shown in the example.

Options¶

test_hofx is optional as a way to test against a reference value when running the test_ObsOperator.x application instead of the test_ObsFilters.x application.

Example¶

- filter: Bounds Check
  filter variables:
  - name: windEastward
  - name: windNorthward
  test variables:
  - name: ObsFunction/SatWindsLNVDCheck
    options:
      test_hofx: GsiHofX
  maxvalue: 3