Model surface pressureΒΆ

Performs a variable conversion to presure at model surface height from:

  • Station pressure (stationPressure)

  • Pressure reduced to sea level (pressureReducedToMeanSeaLevel)

  • The derived height of a standard pressure surface (standardPressure)

Transform: PStar

obs filters:
- filter: Variable Transforms
  Transform: PStar

Observation parameters needed (JEDI name)

The default option for this transform requires the following observed variables:

  • stationPressure

  • pressureReducedToMeanSeaLevel

  • standardPressure

The following GeoVaLs are also required:

  • surf_param_a (\(A\))

  • surf_param_b (\(B\))

  • height

  • stationPressure (\(P_{*b}\))

Method(s) available

Only one method is available, shared across all center options. (Any setting of METHOD will result in using this unique method.) Setting METHOD can be omitted.

The derivation of observed pressure at the model surface is separated into two steps:

  1. Determine the background pressure at the observation location,

    \[P_{rb} = \left[\frac{A - z}{B}\right]^{g/RL},\]

    where \(z\) is the height of the observation and \(g\), \(R\) and \(L\) are standard constants.

  2. Calculate the observed pressure at model level:

    \[P_{*o} = P_{ro}\frac{P_{*b}}{P_{rb}}\]

    where \(P_{ro}\) is the observed pressure value.

The surface pressure is calculated for all observed pressures. A set of diagnostic flags, and the existence of the observed pressures, are used to determine which of the derived \(P_{*o}\) are used as the final observed surface pressure.

Formulation(s) available

None