Eastward (u) and northward (v) wind component

Performs a variable conversion from wind speed and direction to the eastward (u) and northward (v) wind component.

Transform: WindComponents

obs filters:
- filter: Variable Transforms
  Transform: WindComponents

Observation parameters needed (JEDI name)

The default option for this transform requires the following variables:

  • windSpeed (\(V_{s}\))

  • windDirection (\(V_{d}\))

It is possible to change the default variables by setting the following options in the yaml:

  • wind direction variable

  • wind speed variable

  • group

For example the surface wind speed and direction can be transformed using the following:

obs filters:
- filter: Variable Transforms
  Transform: WindComponents
  wind speed variable: windSpeedAt10M
  wind direction variable: windDirectionAt10M

The group option can be set to transform wind speed and direction from a group other than ObsValue.

Method(s) available

Only one method is available. (Any setting of METHOD will result in using this unique method.) Setting METHOD can be omitted.

The eastward (\(u\)) and northward (\(v\)) wind component are derived as follow:

\[ \begin{align}\begin{aligned}u = -V_{s} \times sin(V_{d} \times \frac{\pi}{180})\\v = -V_{s} \times cos(V_{d} \times \frac{\pi}{180})\end{aligned}\end{align} \]

Wind speed and direction

Performs a variable conversion from eastward (u) and northward (v) wind components to wind speed and direction.

Transform: WindSpeedAndDirection

obs filters:
- filter: Variable Transforms
  Transform: WindSpeedAndDirection

Observation parameters needed (JEDI name)

The default option for this transform requires the following variables:

  • windEastward (\(u\))

  • windNorthward (\(v\))

It is possible to change the default variables by setting the following options in the yaml:

  • eastward wind variable

  • northward wind variable

  • group

For example the surface wind speed and direction can be transformed using the following:

obs filters:
- filter: Variable Transforms
  Transform: WindSpeedAndDirection
  eastward wind variable: windEastwardAt10M
  northward wind variable: windNorthwardAt10M

The group option can be set to transform eastward and northward wind from a group other than ObsValue.

Method(s) available

Only one method is available. (Any setting of METHOD will result in using this unique method.) Setting METHOD can be omitted.

The wind speed (\(V_{s}\)) and direction (\(V_{d}\)) are derived as follows:

\[ \begin{align}\begin{aligned}V_{s} = \sqrt{u^{2}+v^{2}}\\V_{d} = \mod((270.0 - \arctan(v, u) \times \frac{\pi}{180}), \frac{\pi}{180})\end{aligned}\end{align} \]