Science calculations

Calculus

aeolus.calc.d_dx(cube, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Calculate a derivative w.r.t. x-coordinate.

aeolus.calc.d_dy(cube, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Calculate a derivative w.r.t. y-coordinate.

aeolus.calc.d_dz(cube, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Calculate a derivative w.r.t. z-coordinate.

aeolus.calc.deriv(cube, coord)[source]

Calculate a derivative w.r.t. the given coordinate.

Uses iris.analysis.calculus.differentiate and then interpolates the result to the grid points of the original cube.

Parameters
Returns

d(cube)/d(coord).

Return type

iris.cube.Cube

See also

aeolus.calc.calculus.d_dx(), aeolus.calc.calculus.d_dy(), aeolus.calc.calculus.d_dz()

aeolus.calc.div_h(i_cube, j_cube, r_planet=None, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Calculate horizontal divergence.

Note: currently works only in spherical coordinates.

Parameters

  • i_cube – i-component (e.g. u-wind)

  • j_cube – j-component (e.g. v-wind)

  • r_planet (float, optional) – Radius of the planet (m). If not given, an attempt is made to get it from the cube metadata.

  • model (aeolus.model.Model, optional) – Model class with relevant variable names.

Returns

Cube of horizontal divergence.

Return type

iris.cube.Cube

Notes

Divergence in spherical coordinates is defined as

\[\nabla\cdot \vec A = \frac{1}{r cos \theta} ( \frac{\partial \vec A_\lambda}{\partial \lambda} + \frac{\partial}{\partial \theta} (\vec A_\theta cos \theta))\]

where lambda is longitude, theta is latitude.

aeolus.calc.integrate(cube, coord)[source]

Integrate the cube along a 1D coordinate using the trapezoidal rule.

Note: coord must be one of the dimensional coordinates of the cube.

Parameters
Returns

Integrated cube.

Return type

iris.cube.Cube

Statistics

aeolus.calc.cumsum(cube, axis, axis_weights=False, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Cumulative sum of a cube.

Parameters

  • cube (iris.cube.Cube) – Input cube.

  • axis (str) – Coordinate axis of operation (t|z|y|x).

  • axis_weights (bool, optional) – If True, multiply data by the coordinate spacings.

  • model (aeolus.model.Model, optional) – Model class with a relevant coordinate name.

Returns

Cube of cumulative sums with the same dimensions as the input cube.

Return type

iris.cube.Cube

aeolus.calc.spatial(cube, aggr, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Calculate spatial statistic with geographic grid weights.

Parameters

  • cube (iris.cube.Cube) – Cube with longitude and latitude coordinates.

  • aggr (str) – Statistical aggregator (see iris.analysis for available aggregators).

  • model (aeolus.model.Model, optional) – Model class with relevant coordinate names.

Returns

Collapsed cube.

Return type

iris.cube.Cube

Examples

>>> spatial(my_data_cube, "mean")
aeolus.calc.spatial_quartiles(cube, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Calculate quartiles over horizontal coordinates.

aeolus.calc.minmaxdiff(cubelist, name)[source]

Spatial maximum minus spatial minimum for a given cube.

Parameters
Returns

Difference between the extrema with collapsed spatial dimensions.

Return type

iris.cube.Cube

aeolus.calc.region_mean_diff(cubelist, name, region_a, region_b)[source]

Difference between averages over two regions for a given cube.

Parameters
Returns

Difference between the region averages with collapsed spatial dimensions.

Return type

iris.cube.Cube

aeolus.calc.meridional_mean(cube, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Calculate cube’s meridional average.

Parameters

  • cube (iris.cube.Cube) – Cube with a latitude coordinate.

  • model (aeolus.model.Model, optional) – Model class with a relevant coordinate name.

Returns

Collapsed cube.

Return type

iris.cube.Cube

aeolus.calc.normalize_cube(cube)[source]

Normalize cube data, i.e. make the values range from 0 to 1.

\[z_i = (x_i - min(x)) / (max(x) - min(x))\]
Parameters

cube (iris.cube.Cube) – The input cube.

aeolus.calc.zonal_mean(cube, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Calculate cube’s zonal average.

Parameters

  • cube (iris.cube.Cube) – Cube with a latitude coordinate.

  • model (aeolus.model.Model, optional) – Model class with a relevant coordinate name.

Returns

Collapsed cube.

Return type

iris.cube.Cube

aeolus.calc.last_n_day_mean(cube, days=365, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Average the cube over the last n days of its time dimension.

aeolus.calc.vertical_mean(cube, weight_by=None, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Vertical mean of a cube with optional weighting.

Parameters

  • cube (iris.cube.Cube) – Cube to average.

  • weight_by (str or iris.coords.Coord or iris.cube.Cube, optional) – Coordinate of the given cube or another cube used for weighting.

  • model (aeolus.model.Model, optional) – Model class with a relevant coordinate name.

Returns

Collapsed cube.

Return type

iris.cube.Cube

Diagnostics

aeolus.calc.air_density(cubelist, const=None, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Get air density from the given cube list.

If not present, it is attempted to calculate it from pressure and temperature.

Parameters

  • cubelist (iris.cube.CubeList) – Input list of cubes containing temperature.

  • const (aeolus.const.const.ConstContainer, optional) – Must have dry_air_gas_constant as an attribute. If not given, an attempt is made to retrieve it from cube attributes.

  • model (aeolus.model.Model, optional) – Model class with relevant variable names.

Returns

Cube of air density.

Return type

iris.cube.Cube

aeolus.calc.air_temperature(cubelist, const=None, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Get the real temperature from the given cube list.

If not present, it is attempted to calculate it from other variables, Exner pressure or air pressure, and potential temperature.

Parameters

  • cubelist (iris.cube.CubeList) – Input list of cubes containing temperature.

  • const (aeolus.const.const.ConstContainer, optional) – Must have reference_surface_pressure and dry_air_gas_constant as attributes. If not given, an attempt is made to retrieve it from cube attributes.

  • model (aeolus.model.Model, optional) – Model class with relevant variable names.

Returns

Cube of air temperature.

Return type

iris.cube.Cube

aeolus.calc.bond_albedo(cubelist, const=None, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Bold albedo.

\[4 \frac{OSR_{TOA}}{S_{0}}\]
Parameters

  • cubelist (iris.cube.CubeList) – Input list of cubes.

  • const (aeolus.const.const.ConstContainer, optional) – Must have a ScalarCube of condensible_density as an attribute. If not given, attempt to retrieve it from cube attributes.

  • model (aeolus.model.Model, optional) – Model class with relevant variable names.

Returns

Cube of bond albedo.

Return type

iris.cube.Cube

aeolus.calc.dry_lapse_rate(cubelist, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Dry lapse rate, or the change of air temperature with altitude.

\[\gamma = \partial T_{air} / \partial z\]
Parameters

  • cubelist (iris.cube.CubeList) – Input list of cubes containing temperature.

  • model (aeolus.model.Model, optional) – Model class with relevant variable names.

Returns

Cube of dT/dz.

Return type

iris.cube.Cube

aeolus.calc.flux(cubelist, quantity, axis, weight_by_density=True, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Calculate horizontal or vertical flux of some quantity.

\[F_{x} = u (\rho q), F_{y} = v (\rho q), F_{z} = w (\rho q)\]
Parameters

  • cubelist (iris.cube.CubeList) – Input list of cubes.

  • quantity (str or iris.Constraint) – Quantity (present in the cube list).

  • axis (str) – Axis of the flux component (x|y|z)

  • weight_by_density (bool, optional) – Multiply by a cube of air density (must be present in the input cube list).

  • model (aeolus.model.Model, optional) – Model class with relevant variable names.

Returns

Cube of a flux component with the same dimensions as input cubes.

Return type

iris.cube.Cube

aeolus.calc.geopotential_height(cubelist, const=None, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Get geopotential height from the given cube list.

If not present, the altitude coordinate is transformed into a cube.

Parameters

  • cubelist (iris.cube.CubeList) – Input list of cubes containing temperature.

  • const (aeolus.const.const.ConstContainer, optional) – Must have gravity as an attribute. If not given, an attempt is made to retrieve it from cube attributes.

  • model (aeolus.model.Model, optional) – Model class with relevant variable names.

Returns

Cube of geopotential height.

Return type

iris.cube.Cube

aeolus.calc.ghe_norm(cubelist, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Normalised greenhouse effect parameter.

\[GHE = 1 - \left(\frac{T_{eff}}{T_{sfc}}\right)^{1/4}\]
Parameters

  • cubelist (iris.cube.CubeList) – Input list of cubes.

  • model (aeolus.model.Model, optional) – Model class with relevant variable names.

Returns

Cube of greenhouse effect parameter with collapsed spatial dimensions.

Return type

iris.cube.Cube

aeolus.calc.heat_redist_eff(cubelist, region_a, region_b, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Heat redistribution efficiency (Leconte et al. 2013).

\[\eta=\frac{OLR_{TOA,night}}{OLR_{TOA,day}}\]
Parameters
Returns

Cube of eta parameter with collapsed spatial dimensions.

Return type

iris.cube.Cube

aeolus.calc.horiz_wind_cmpnts(cubelist, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Extract u and v wind components from a cube list and interpolate v on u’s grid if necessary.

Parameters

  • cubelist (iris.cube.CubeList) – List of cubes with horizontal wind components

  • model (aeolus.model.Model, optional) – Model class with relevant variable names.

Returns

u, v – Cubes of wind components.

Return type

iris.cube.Cube

aeolus.calc.precip_sum(cubelist, ptype='total', const=None, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Calculate a sum of different types of precipitation [\(mm~day^{-1}\)].

Parameters

  • cubelist (iris.cube.CubeList) – Input list of cubes.

  • ptype (str, optional) – Precipitation type (total|stra|conv|rain|snow).

  • const (aeolus.const.const.ConstContainer, optional) – Must have a ScalarCube of condensible_density as an attribute. If not given, attempt to retrieve it from cube attributes.

  • model (aeolus.model.Model, optional) – Model class with relevant variable names.

Returns

Sum of cubes of precipitation with units converted to mm per day.

Return type

iris.cube.Cube

aeolus.calc.sfc_net_energy(cubelist, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Calculate domain-average surface energy flux.

Parameters

  • cubelist (iris.cube.CubeList) – Input list of cubes with net LW and SW radiation, sensible and latent surface fluxes.

  • model (aeolus.model.Model, optional) – Model class with relevant variable names.

Returns

Cube of total surface downward energy flux.

Return type

iris.cube.Cube

aeolus.calc.sfc_water_balance(cubelist, const=None, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Calculate domain-average precipitation minus evaporation.

Parameters

  • cubelist (iris.cube.CubeList) – Input list of cubes.

  • const (aeolus.const.const.ConstContainer, optional) – Must have a ScalarCube of condensible_density as an attribute. If not given, attempt is made to retrieve it from cube attributes.

  • model (aeolus.model.Model, optional) – Model class with relevant variable names.

Returns

Cube of total surface downward water flux (P-E).

Return type

iris.cube.Cube

aeolus.calc.superrotation_index(cubelist, const=None, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Local superrotation index.

\[ \begin{align}\begin{aligned}s = \frac{m}{\Omega a^2} - 1,\\m = a cos\phi(\Omega a cos\phi + u)\end{aligned}\end{align} \]
Parameters

  • cubelist (iris.cube.CubeList) – List of cubes containing a cube of zonal velocity (u).

  • model (aeolus.model.Model, optional) – Model class with relevant variable names.

Returns

s_idx – Cubes of superrotation index.

Return type

iris.cube.Cube

References

Read (1986), https://doi.org/10.1002/qj.49711247114

aeolus.calc.toa_cloud_radiative_effect(cubelist, kind, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Calculate domain-average TOA cloud radiative effect (CRE).

\[CRE_{TOA} = F_{up,clear-sky} - F_{up,all-sky}\]
Parameters

  • cubelist (iris.cube.CubeList) – Input list of cubes

  • kind (str) – Shortwave (‘sw’), longwave (‘lw’), or ‘total’ CRE

Returns

Cube of CRE.

Return type

iris.cube.Cube

aeolus.calc.toa_eff_temp(cubelist, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Calculate effective temperature from TOA OLR.

Parameters

  • cubelist (iris.cube.CubeList) – Input list of cubes.

  • model (aeolus.model.Model, optional) – Model class with relevant variable names.

Returns

Cube of \(T_{eff}\).

Return type

iris.cube.Cube

aeolus.calc.toa_net_energy(cubelist, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Calculate domain-average TOA energy flux.

Parameters

  • cubelist (iris.cube.CubeList) – Input list of cubes.

  • model (aeolus.model.Model, optional) – Model class with relevant variable names.

Returns

Cube of total TOA downward energy flux.

Return type

iris.cube.Cube

aeolus.calc.water_path(cubelist, kind='water_vapour', model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Water vapour or condensate path, i.e. a vertical integral of a water phase.

\[WP = \int_{z_{sfc}}^{z_{top}} \rho q dz\]
Parameters

  • cubelist (iris.cube.CubeList) – Input list of cubes containing appropriate mixing ratio and air density.

  • kind (str, optional) – Short name of the water phase to be integrated. Options are water_vapour (default) | liquid_water | ice_water | cloud_water cloud_water is the sum of liquid and ice phases.

  • model (aeolus.model.Model, optional) – Model class with relevant coordinate names. model.z is used as a vertical coordinate for integration.

Returns

Cube of water path with collapsed vertical dimension.

Return type

iris.cube.Cube

Horizontal fluxes

aeolus.calc.net_horizontal_flux_to_region(scalar_cube, region, u, v, r_planet=None, vertical_constraint=None, model=<class 'aeolus.model.base.Model'>(53 fields))[source]

Calculate horizontal fluxes of scalar_cube quantity and add them to get the net result.