read_GRACE_harmonics

  • Reads GRACE/GRACE-FO files and extracts spherical harmonic data and drift rates (RL04)

  • Adds drift rates to clm and slm for Release-4 harmonics

  • Correct Release-5 GSM data for drift in pole tide

  • Extracts start and end date of GRACE/GRACE-FO files and calculates mean of range

Calling Sequence

from gravity_toolkit.read_GRACE_harmonics import read_GRACE_harmonics
CSR_L2_input = read_GRACE_harmonics('GSM-2_2002095-2002120_0021_UTCSR_0060_0005.gz',60)
GFZ_L2_input = read_GRACE_harmonics('GSM-2_2002094-2002120_0024_EIGEN_G---_005a.gz',90)
JPL_L2_input = read_GRACE_harmonics('GSM-2_2002091-2002120_0018_JPLEM_0001_0005.gz',60)
JPLMSC_input = read_GRACE_harmonics('GSM-2_2003001-2003031_0029_JPLMSC_0719_0005',719)

Source code

gravity_toolkit.read_GRACE_harmonics(input_file, LMAX, **kwargs)[source]

Extracts spherical harmonic coefficients from GRACE/GRACE-FO files

Parameters:
input_file: str

GRACE/GRACE-FO Level-2 spherical harmonic data file

LMAX: int

Maximum degree of spherical harmonics (degree of truncation)

MMAX: int or NoneType, default None

Maximum order of spherical harmonics

POLE_TIDE: bool, default False

Correct for pole tide drift following Wahr et al. [74]

Returns:
time: float

mid-month date in year-decimal

start: float

start date of range as Julian day

end: float

end date of range as Julian day

l: np.ndarray

spherical harmonic degree to LMAX

m: np.ndarray

spherical harmonic order to MMAX

clm: np.ndarray

cosine spherical harmonics coefficients

slm: np.ndarray

sine spherical harmonics coefficients

eclm: np.ndarray

cosine spherical harmonic uncalibrated standard deviations

eslm: np.ndarray

sine spherical harmonic uncalibrated standard deviations

header: str

Header text from the GRACE/GRACE-FO file

gravity_toolkit.read_GRACE_harmonics.parse_file(input_file)[source]

Extract parameters from filename

Parameters:
input_file: str

GRACE/GRACE-FO Level-2 spherical harmonic data file

gravity_toolkit.read_GRACE_harmonics.extract_file(input_file, compressed)[source]

Read input file and extract contents

Parameters:
input_file: str

GRACE/GRACE-FO Level-2 spherical harmonic data file

compressed: bool

denotes if the file is compressed