Skip to content

variable_list.md

Latest commit

 

History

History
108 lines (71 loc) · 4.29 KB

variable_list.md

File metadata and controls

108 lines (71 loc) · 4.29 KB
Raw

CliMA Variable List

This document unifies the naming conventions used across the CliMA codebase. It defines 'reserved' variable names in <property>_<species> format with the default working fluid (no-subscript) being moist air.

Type parameters

The Julia code typically uses T as a type parameter, however this conflicts with the typical usage for temperature. Instead, good choices are:

  • FT for floating point values

Names reserved for debug variables

  • dummy
  • scratch

Working Fluid and Equation of State

  • q_dry = dry air mass fraction

  • q_vap = specific humidity, vapor

  • q_liq = specific humidity, liquid

  • q_ice = specific humidity, ice

  • q_tot = specific humidity, total

  • ρ = density (no subscript = moist air)

  • R_m = gas constant, moist

  • R_d = gas constant, dry

  • R_v = gas constant, water vapor

  • T = temperature, moist air

Time

  • dt = time increment

Momentum

  • u = x-velocity
  • v = y-velocity
  • w = z-velocity

Energy balance

Lowercase e_<type> indicates a specific (per-unit-mass) quantity. The corresponding density-weighted volumetric forms used as prognostic variables are ρe_<type> (see "Prognostic variable conventions" below).

  • e_kin_<spe> = specific energy per unit mass, kinetic

  • e_pot_<spe> = specific energy per unit mass, potential

  • e_int_<spe> = specific energy per unit mass, internal

  • e_tot_<spe> = specific energy per unit mass, total

  • cv_m, cv_d, cv_l, cv_v, cv_i = isochoric specific heat capacities [J/(kg·K)] (moist, dry, liquid, vapor, ice)

  • cp_m, cp_d, cp_l, cp_v, cp_i = isobaric specific heat capacities [J/(kg·K)] (moist, dry, liquid, vapor, ice)

Microphysics

Specific humidities of precipitation and cloud-condensate species:

  • q_rai = specific humidity, rain [kg/kg]
  • q_sno = specific humidity, snow [kg/kg]
  • q_lcl = specific humidity, cloud liquid [kg/kg]
  • q_icl = specific humidity, cloud ice [kg/kg]

By convention, when all partitions of the phase of water are included, we use

  • q_liq = specific humidity, all liquid
  • q_ice = specific humidity, all ice

Terminal velocities are per-species:

  • terminal_velocity_<spe> = mass-weighted terminal fall speed of <spe> [m/s]: e.g. terminal_velocity_rai, terminal_velocity_sno

Microphysical tendencies [kg/kg/s]. Sign convention: positive means a source for the species in the to-position of the name.

  • conv_q_lcl_to_q_rai = autoconversion: cloud liquid → rain
  • conv_q_icl_to_q_sno = ice autoconversion: cloud ice → snow
  • conv_q_vap_to_q_lcl_icl = condensation / deposition: vapor → cloud condensate (signed; negative values represent evaporation / sublimation back to vapor)
  • evaporation_sublimation = rain evaporation / snow sublimation; positive = vapor source
  • accretion = collection of cloud condensate by precipitation; positive = precipitation source

Thermodynamic state and pressure

  • p = pressure (no subscript = total pressure of moist air) [Pa]
  • θ = potential temperature [K]
  • θ_liq_ice = liquid–ice potential temperature [K]
  • Φ = geopotential [m²/s²]
  • grav = gravitational acceleration [m/s²]
  • L_v = latent heat of vaporization [J/kg]
  • L_s = latent heat of sublimation [J/kg]
  • L_f = latent heat of fusion [J/kg]

Note: in CliMA tendency-style signatures f!(Yₜ, Y, p, t, …), the local name p refers to the cache, not pressure.

Prognostic variable conventions

CliMA models typically integrate density-weighted forms as prognostic variables and diagnose specific quantities from them inside tendencies:

  • ρq_<spe> = density × specific humidity of species <spe> (e.g. ρq_tot, ρq_liq, ρq_rai) [kg/m³]
  • ρe_tot = density × total specific energy [J/m³]

Field Prefixes (ClimaCore-based repos)

In repos that use ClimaCore for spatial discretization, functions that return fields are prefixed by their staggered-grid location:

  • ᶜ<name> (typed \^c<TAB>) = field at cell centers
  • ᶠ<name> (typed \^f<TAB>) = field at cell faces

For example, ᶜρ(Y, p) is a cell-center density field. The prefix lives on the function, not on the stored field: state-vector fields like Y.c.ρ are themselves cell-centered but do not carry the prefix.

Self-correction

If this guide is discovered to be stale or missing a pattern, update it.