gen_disc_load

  • Calculates gravitational spherical harmonic coefficients for a uniform disc load

Calling Sequence

from gravity_toolkit.gen_disc_load import gen_disc_load
from gravity_toolkit.associated_legendre import plm_holmes
PLM, dPLM = plm_holmes(LMAX, np.cos(th))
Ylms = gen_disc_load(data, lon, lat, area, LMAX=LMAX, PLM=PLM, LOVE=(hl,kl,ll))

Source code

gravity_toolkit.gen_disc_load(data, lon, lat, area, LMAX=60, MMAX=None, UNITS=2, PLM=None, LOVE=None)[source]

Calculates spherical harmonic coefficients for a uniform disc load [19, 26, 30, 40, 50]

Parameters:
data: np.ndarray

data magnitude (Gt)

lon: np.ndarray

longitude of disc center

lat: np.ndarray

latitude of disc center

area: float

area of disc (km2)

LMAX: int, default 60

Upper bound of Spherical Harmonic Degrees

MMAX: int or NoneType, default None

Upper bound of Spherical Harmonic Orders

UNITS: int, default 2

Input data units

  • 1: cm water equivalent thickness (cm w.e., g/cm2)

  • 2: gigatonnes of mass (Gt)

  • 3: mm water equivalent thickness (mm w.e., kg/m2)

  • list: custom unit conversion factor

PLM: np.ndarray or NoneType, default None

Legendre polynomials for cos(theta) (disc center)

LOVE: tuple or NoneType, default None

Load Love numbers up to degree LMAX (hl, kl, ll)

Returns:
clm: np.ndarray

cosine spherical harmonic coefficients (geodesy normalization)

slm: np.ndarray

sine spherical harmonic coefficients (geodesy normalization)

l: np.ndarray

spherical harmonic degree to LMAX

m: np.ndarray

spherical harmonic order to MMAX