Vader Variable Changes

Each variable change that can be performed by Vader is defined by code called a “Recipe” (from a design metaphor within the Vader code.) Each recipe shares the same structure:

• Name - The name of the recipe which can be used in yaml to specify the recipe parameters. (Follows the recipe naming standard.)

• Variable Produced - The variable that will be created by the algorithm, usually called the “product”.

• Input Variables - Usually called “ingredients”, these are the variables required as input for the algorithms.

• Number of Levels - The number of levels for the Atlas Field for the product. Must be a constant or a function of the number of levels of the ingredients.

• FunctionSpace - The Atlas FunctionSpace for the Atlas Field for the product. Can be specific FunctionSpace or the same as one of the ingredients.

• hasTLAD - This is a boolean flag indicating whether the recipe has implemented the tangent linear and adjoint (TL/AD) of the transformation. (These are optional, while the non-linear transformation is required.)

• Algorithms - Put into methods called executeNL (and executeTL and executeAD if hasTLAD is true), this code performs the calculations on the inputs and produces the output.

• Required Configuration Variables - Some recipes reference values that are stored in VADER’s configuration variables. These variables must be defined in the VaderConstructConfig class that is passed to the VADER constructor.

• Parameters - Recipes can have optional parameters which can configure their behavior. These parameters should not be required.

Below is a list of the recipes that have been implemented in VADER:

• Air Temperature
  • Potential Temperature from temperature and surface pressure
  • Potential Temperature from temperature and pressure to kappa
  • Temperature from potential temperature and exner
  • Temperature from virtual temperature and specific humidity
  • Virtual Temperature from potential temperature and exner
  • Virtual Potential Temperature from height and hydrostatic exner
  • Virtual Potential Temperature from specific humidity and potential temperature
• Air Pressure
  • Air pressure at midpoints from air pressure at interface
  • Air pressure at interface from ak/bk
  • Air pressure at interface from pressure thickness
  • Log of air pressure at interface from air pressure at interface
  • Air pressure thickness from pressure at interface
  • Air pressure to kappa from air pressure at interface
  • Surface air pressure from air pressure thickness
  • Dry air density levels minus one from virtual potential temperature and pressure
  • Hydrostatic exner levels from height, virtual potential temperature, and air pressure.
• Atmospheric Water
  • Cloud ice mixing ratio wrt moist air and condensed water, from cloud ice mixing ratio and total water mixing ratio
  • Cloud liquid water mixing ratio wrt moist air and condensed water, from rain mixing ratio and total water mixing ratio
  • Rain mixing ratio wrt moist air and condensed water from rain and total water mixing ratios
  • Relative humidity
  • Total water mixing ratio wrt dry air from individual mixing ratios wrt dry air
  • Total water mixing ratio wrt moist air and condensed water from specific humidity and other moisture mixing ratios
  • (Met Office) specific humidity from water vapor and total water mixing ratios wrt dry air
  • (Met Office) specific humidity at 2m from (Met Office) specific humidity
• Wind
  • U-wind at 10m from eastward wind
  • V-wind at 10m from northward wind
• Marine
  • Sea Water Potential Temperature from temperature, salinity, location, and depth
  • Sea Water Temperature from potential temperature, salinity, location, and depth