Parameterize the observation error as a piece-wise linear function of a ufo::Variable.
The output function is specified by the coordinates of the inflection points and includes:
- initial constant value
- linear growth or decay (ramp)
- final constant value
err1 |- - - *---
| ,'.
| ,' .
| ,' .
err0 |--*' .
| . .
'--+-------+---
' '
x0 x1
Notes:
- for a decaying ramp, set err1 < err0
- for a step function, set x0 == x1
example configurations for a FilterBase derived class:
- Filter: {Filter Name}
AMSUA
filter variables:
- name: brightness_temperature
channels: &errassignchan 1-15
action:
name: assign error
error function:
name: ObsErrorModelRamp@ObsFunction
channels: *errassignchan
options:
channels: *errassignchan
xvar:
name: CLWRetMean@ObsFunction
options:
clwret_ch238: 1
clwret_ch314: 2
clwret_types: [ObsValue, HofX]
bias_application: HofX
x0: [ 0.050, 0.030, 0.030, 0.020, 0.000,
0.100, 0.000, 0.000, 0.000, 0.000,
0.000, 0.000, 0.000, 0.000, 0.030]
x1: [ 0.600, 0.450, 0.400, 0.450, 1.000,
1.500, 0.000, 0.000, 0.000, 0.000,
0.000, 0.000, 0.000, 0.000, 0.200]
err0: [ 2.500, 2.200, 2.000, 0.550, 0.300,
0.230, 0.230, 0.250, 0.250, 0.350,
0.400, 0.550, 0.800, 3.000, 3.500]
err1: [20.000, 18.000, 12.000, 3.000, 0.500,
0.300, 0.230, 0.250, 0.250, 0.350,
0.400, 0.550, 0.800, 3.000, 18.000]
{save: true}
ABI/AHI
filter variables:
- name: brightness_temperature
channels: &errassignchan 8-10
action:
name: assign error
error function:
name: ObsErrorModelRamp@ObsFunction
channels: *errassignchan
options:
channels: *errassignchan
xvar:
name: SymmCldImpactIR@ObsFunction
channels: *errassignchan
options:
channels: *errassignchan
x0: [ 0.0, 0.0, 1.0]
x1: [15.0, 20.0, 25.0]
err0: [ 2.5, 3.2, 3.2]
err1: [17.0, 20.5, 21.1]
Non-radiance ObsTypes
filter variables:
- name: {filter variable name}
action:
name: assign error
error function:
name: ObsErrorModelRamp@ObsFunction
options:
xvar:
name: {xvar}@[ObsFunction, GeoVaLs, ObsDiag, ObsValue, etc...]
options: {xvar options}
x0: [{X0}]
x1: [{X1}]
err0: [{ERR0}]
err1: [{ERR1}]
Definition at line 157 of file ObsErrorModelRamp.h.