calc

This module contains a variety of meteorological calculations.

Dry Thermodynamics

add_height_to_pressure(pressure, height)	Calculate the pressure at a certain height above another pressure level.
add_pressure_to_height(height, pressure)	Calculate the height at a certain pressure above another height.
density(pressure, temperature, mixing[, …])	Calculate density.
dry_lapse(pressure, temperature)	Calculate the temperature at a level assuming only dry processes.
dry_static_energy(heights, temperature)	Calculate the dry static energy of parcels.
geopotential_to_height(geopot)	Compute height from a given geopotential.
height_to_geopotential(height)	Compute geopotential for a given height.
height_to_pressure_std(height)	Convert height data to pressures using the U.S.
mean_pressure_weighted(pressure, *args, **kwargs)	Calculate pressure-weighted mean of an arbitrary variable through a layer.
potential_temperature(pressure, temperature)	Calculate the potential temperature.
pressure_to_height_std(pressure)	Convert pressure data to heights using the U.S.
sigma_to_pressure(sigma, psfc, ptop)	Calculate pressure from sigma values.
static_stability(pressure, temperature[, axis])	Calculate the static stability within a vertical profile.
temperature_from_potential_temperature(…)	Calculate the temperature from a given potential temperature.
thickness_hydrostatic(pressure, temperature, …)	Calculate the thickness of a layer via the hypsometric equation.

Moist Thermodynamics

dewpoint(e)	Calculate the ambient dewpoint given the vapor pressure.
dewpoint_from_specific_humidity(…)	Calculate the dewpoint from specific humidity, temperature, and pressure.
dewpoint_rh(temperature, rh)	Calculate the ambient dewpoint given air temperature and relative humidity.
equivalent_potential_temperature(pressure, …)	Calculate equivalent potential temperature.
mixing_ratio(part_press, tot_press[, …])	Calculate the mixing ratio of a gas.
mixing_ratio_from_relative_humidity(…)	Calculate the mixing ratio from relative humidity, temperature, and pressure.
mixing_ratio_from_specific_humidity(…)	Calculate the mixing ratio from specific humidity.
moist_lapse(pressure, temperature)	Calculate the temperature at a level assuming liquid saturation processes.
moist_static_energy(heights, temperature, …)	Calculate the moist static energy of parcels.
precipitable_water(dewpt, pressure[, …])	Calculate precipitable water through the depth of a sounding.
psychrometric_vapor_pressure_wet(…[, …])	Calculate the vapor pressure with wet bulb and dry bulb temperatures.
relative_humidity_from_dewpoint(temperature, …)	Calculate the relative humidity.
relative_humidity_from_mixing_ratio(…)	Calculate the relative humidity from mixing ratio, temperature, and pressure.
relative_humidity_from_specific_humidity(…)	Calculate the relative humidity from specific humidity, temperature, and pressure.
relative_humidity_wet_psychrometric(…)	Calculate the relative humidity with wet bulb and dry bulb temperatures.
saturation_equivalent_potential_temperature(…)	Calculate saturation equivalent potential temperature.
saturation_mixing_ratio(tot_press, temperature)	Calculate the saturation mixing ratio of water vapor.
saturation_vapor_pressure(temperature)	Calculate the saturation water vapor (partial) pressure.
specific_humidity_from_mixing_ratio(mixing_ratio)	Calculate the specific humidity from the mixing ratio.
thickness_hydrostatic_from_relative_humidity(…)	Calculate the thickness of a layer given pressure, temperature and relative humidity.
vapor_pressure(pressure, mixing)	Calculate water vapor (partial) pressure.
vertical_velocity(omega, pressure, temperature)	Calculate w from omega assuming hydrostatic conditions.
vertical_velocity_pressure(w, pressure, …)	Calculate omega from w assuming hydrostatic conditions.
virtual_potential_temperature(pressure, …)	Calculate virtual potential temperature.
virtual_temperature(temperature, mixing[, …])	Calculate virtual temperature.
wet_bulb_temperature(pressure, temperature, …)	Calculate the wet-bulb temperature using Normand’s rule.

Soundings

bulk_shear(pressure, u, v[, heights, …])	Calculate bulk shear through a layer.
bunkers_storm_motion(pressure, u, v, heights)	Calculate the Bunkers right-mover and left-mover storm motions and sfc-6km mean flow.
cape_cin(pressure, temperature, dewpt, …)	Calculate CAPE and CIN.
critical_angle(pressure, u, v, heights, …)	Calculate the critical angle.
el(pressure, temperature, dewpt[, …])	Calculate the equilibrium level.
lcl(pressure, temperature, dewpt[, …])	Calculate the lifted condensation level (LCL) using from the starting point.
lfc(pressure, temperature, dewpt[, …])	Calculate the level of free convection (LFC).
mixed_layer(p, *args, **kwargs)	Mix variable(s) over a layer, yielding a mass-weighted average.
mixed_parcel(p, temperature, dewpt[, …])	Calculate the properties of a parcel mixed from a layer.
most_unstable_cape_cin(pressure, …)	Calculate most unstable CAPE/CIN.
most_unstable_parcel(pressure, temperature, …)	Determine the most unstable parcel in a layer.
parcel_profile(pressure, temperature, dewpt)	Calculate the profile a parcel takes through the atmosphere.
parcel_profile_with_lcl(pressure, …)	Calculate the profile a parcel takes through the atmosphere.
significant_tornado(sbcape, …)	Calculate the significant tornado parameter (fixed layer).
storm_relative_helicity(u, v, heights, depth)	Calculate storm relative helicity.
supercell_composite(mucape, …)	Calculate the supercell composite parameter.
surface_based_cape_cin(pressure, …)	Calculate surface-based CAPE and CIN.

Dynamic/Kinematic

absolute_momentum(u_wind, v_wind[, index])	Calculate cross-sectional absolute momentum (also called pseudoangular momentum).
absolute_vorticity(u, v, dx, dy, lats[, …])	Calculate the absolute vorticity of the horizontal wind.
advection(scalar, wind, deltas)	Calculate the advection of a scalar field by the wind.
ageostrophic_wind(heights, f, dx, dy, u, v)	Calculate the ageostrophic wind given from the heights or geopotential.
coriolis_parameter(latitude)	Calculate the coriolis parameter at each point.
divergence(u, v, dx, dy)	Calculate the horizontal divergence of the horizontal wind.
exner_function(pressure[, reference_pressure])	Calculate the Exner function.
frontogenesis(thta, u, v, dx, dy[, dim_order])	Calculate the 2D kinematic frontogenesis of a temperature field.
geostrophic_wind(heights, f, dx, dy)	Calculate the geostrophic wind given from the heights or geopotential.
inertial_advective_wind(u, v, u_geostrophic, …)	Calculate the inertial advective wind.
kinematic_flux(vel, b[, perturbation, axis])	Compute the kinematic flux from two time series.
montgomery_streamfunction(height, temperature)	Compute the Montgomery Streamfunction on isentropic surfaces.
potential_vorticity_baroclinic(…[, axis, …])	Calculate the baroclinic potential vorticity.
potential_vorticity_barotropic(heights, u, …)	Calculate the barotropic (Rossby) potential vorticity.
q_vector(u, v, temperature, pressure, dx, dy)	Calculate Q-vector at a given pressure level using the u, v winds and temperature.
shearing_deformation(u, v, dx, dy)	Calculate the shearing deformation of the horizontal wind.
stretching_deformation(u, v, dx, dy)	Calculate the stretching deformation of the horizontal wind.
total_deformation(u, v, dx, dy)	Calculate the horizontal total deformation of the horizontal wind.
vorticity(u, v, dx, dy)	Calculate the vertical vorticity of the horizontal wind.
wind_components(speed, wdir)	Calculate the U, V wind vector components from the speed and direction.
wind_direction(u, v)	Compute the wind direction from u and v-components.
wind_speed(u, v)	Compute the wind speed from u and v-components.

Boundary Layer/Turbulence

brunt_vaisala_frequency(heights, …[, axis])	Calculate the Brunt-Vaisala frequency.
brunt_vaisala_frequency_squared(heights, …)	Calculate the square of the Brunt-Vaisala frequency.
brunt_vaisala_period(heights, …[, axis])	Calculate the Brunt-Vaisala period.
friction_velocity(u, w[, v, perturbation, axis])	Compute the friction velocity from the time series of velocity components.
tke(u, v, w[, perturbation, axis])	Compute turbulence kinetic energy.

Mathematical Functions

cross_section_components(data_x, data_y[, index])	Obtain the tangential and normal components of a cross-section of a vector field.
first_derivative(f, **kwargs)	Calculate the first derivative of a grid of values.
gradient(f, **kwargs)	Calculate the gradient of a grid of values.
grid_deltas_from_dataarray(f)	Calculate the horizontal deltas between grid points of a DataArray.
laplacian(f, **kwargs)	Calculate the laplacian of a grid of values.
lat_lon_grid_deltas(longitude, latitude, …)	Calculate the delta between grid points that are in a latitude/longitude format.
normal_component(data_x, data_y[, index])	Obtain the normal component of a cross-section of a vector field.
second_derivative(f, **kwargs)	Calculate the second derivative of a grid of values.
tangential_component(data_x, data_y[, index])	Obtain the tangential component of a cross-section of a vector field.
unit_vectors_from_cross_section(cross[, index])	Calculate the unit tanget and unit normal vectors from a cross-section.

Apparent Temperature

apparent_temperature(temperature, rh, speed)	Calculate the current apparent temperature.
heat_index(temperature, rh[, mask_undefined])	Calculate the Heat Index from the current temperature and relative humidity.
windchill(temperature, speed[, …])	Calculate the Wind Chill Temperature Index (WCTI).

Other

find_bounding_indices(arr, values, axis[, …])	Find the indices surrounding the values within arr along axis.
find_intersections(x, a, b[, direction])	Calculate the best estimate of intersection.
get_layer(pressure, *args, **kwargs)	Return an atmospheric layer from upper air data with the requested bottom and depth.
get_layer_heights(heights, depth, *args, …)	Return an atmospheric layer from upper air data with the requested bottom and depth.
get_perturbation(ts[, axis])	Compute the perturbation from the mean of a time series.
isentropic_interpolation(theta_levels, …)	Interpolate data in isobaric coordinates to isentropic coordinates.
nearest_intersection_idx(a, b)	Determine the index of the point just before two lines with common x values.
parse_angle(input_dir)	Calculate the meteorological angle from directional text.
reduce_point_density(points, radius[, priority])	Return a mask to reduce the density of points in irregularly-spaced data.
resample_nn_1d(a, centers)	Return one-dimensional nearest-neighbor indexes based on user-specified centers.
smooth_gaussian(scalar_grid, n)	Filter with normal distribution of weights.

Deprecated

Do not use these functions in new code, please see their documentation for their replacements.

get_wind_components(u, v)	Calculate the U, V wind vector components from the speed and direction.
get_wind_dir(u, v)	Compute the wind direction from u and v-components.
get_wind_speed(u, v)	Compute the wind speed from u and v-components.
interp(x, xp, *args, **kwargs)	Interpolates data with any shape over a specified axis.
interpolate_nans(x, y[, kind])	Interpolate NaN values in y.
lat_lon_grid_spacing(longitude, latitude, …)	Calculate the distance between grid points that are in a latitude/longitude format.
log_interp(x, xp, *args, **kwargs)	Interpolates data with logarithmic x-scale over a specified axis.