read_gfc_harmonics

  • Reads gfc files and extracts spherical harmonics for Swarm and GRAZ GRACE/GRACE-FO data

  • Parses date of GRACE/GRACE-FO data from filename

Calling Sequence

from gravity_toolkit.read_gfc_harmonics import read_gfc_harmonics
Ylms = read_gfc_harmonics(input_file, TIDE='tide_free')

Source code

gravity_toolkit.read_gfc_harmonics(input_file, TIDE=None, FLAG='gfc')[source]

Extract gravity model spherical harmonics from Gravity Field Coefficient (gfc) files

Parameters:
input_file: str

full path to gfc spherical harmonic data file

TIDE: string

Permanent tide system of output gravity fields [43]

  • 'tide_free': no permanent direct and indirect tidal potentials

  • 'mean_tide': permanent tidal potentials (direct and indirect)

  • 'zero_tide': permanent direct tidal potential removed

FLAG: str, default ‘gfc’

Flag denoting data lines

Returns:
time: float

mid-month date in decimal form

start: float

Julian dates of the start date

end: float

Julian dates of the start date

l: np.ndarray

spherical harmonic degree to maximum degree of data

m: np.ndarray

spherical harmonic order to maximum degree of data

clm: np.ndarray

cosine spherical harmonics of input data

slm: np.ndarray

sine spherical harmonics of input data

eclm: np.ndarray

cosine spherical harmonic standard deviations of type errors

eslm: np.ndarray

sine spherical harmonic standard deviations of type errors

modelname: str

name of the gravity model

earth_gravity_constant: str

GM constant of the Earth for gravity model

radius: str

semi-major axis of the Earth for gravity model

max_degree: str

maximum degree and order for gravity model

errors: str

error type of the gravity model

norm: str

normalization of the spherical harmonics

tide_system: str

Permanent tide system of gravity model

  • 'mean_tide'

  • 'zero_tide'

  • 'tide_free'