ObsErrorFactorSurfJacobianRad¶

This obsFunction is designed to compute observation error inflation factor for brightness temperature as a function of weighted surface temperature jacobian and surface emissivity jacobian. The error inflation factor (EIF) is defined as:

\[\text{EIF} = \sqrt{1 + Errinv * Beta}\]

where

\(Errinv\) = inverse of effective observation error variance

\(Beta\) = \({(obserr_{dtempf} * \left| {Jtemp} \right| + obserr_{demisf} * \left| {Jemis} \right| )}^2\)

\(J_{temp}\) = surface temperature jacobian

\(J_{emis}\) = surface emissivity jacobian

\(obserr_{dtempf}\) = empirical constant as a function of surface type applied to Jtemp

\(obserr_{demisf}\) = empirical constant as a function of surface type applied to Jemis

Required input parameters:¶

channels: List of channel to which the observation error factor applies
obserr_dtempf: Observation error scale factors applied to surface temperature jacobians over five surface types: [sea, land, ice, snow and mixed]
obserr_demisf: Observation error scale factors applied to surface emissivity jacobians over five surface types: [sea, land, ice, snow and mixed]

Optional input parameters:¶

test_obserr: Name of the data group to which the observation error is applied (default is ObsErrorData)
test_qcflag: Name of the data group to which the QC flag is applied (default is QCflagsData)

Required fields from obs/geoval:¶

geovals: GeoVaLs/water_area_fraction, GeoVaLs/land_area_fraction, GeoVaLs/ice_area_fraction, GeoVaLs/surface_snow_area_fraction
obsDiag: ObsDiag/brightness_temperature_jacobian_surface_temperature, ObsDiag/brightness_temperature_jacobian_surface_emissivity

In addition, brightness_temperature observation error and QC flags will come from prior filters or from the input files defined by test_obserr and test_qcflag.

Example configurations:¶

Here is an example to use this obsFunction inside a fiter to inflate obs errors.

- filter: Perform Action
  filter variables:
  - name: brightnessTemperature
    channels: *all_channels
  action:
    name: inflate error
    inflation variable:
      name: ObsFunction/ObsErrorFactorSurfJacobianRad
      channels: *all_channels
      options:
        channels: *all_channels
        obserr_demisf: [0.010, 0.020, 0.015, 0.020, 0.200]
        obserr_dtempf: [0.500, 2.000, 1.000, 2.000, 4.500]