GRACE normals processing

[1]:

# Imports
from gfeatpy.gravity import SphericalHarmonicsCovariance, EquivalentWaterHeight
from gfeatpy import plotting

import matplotlib.pyplot as plt

data_root = "../../../data"

Non-resonant case

[2]:

# Load monthly normal matrix
monthly_error = SphericalHarmonicsCovariance(96)
monthly_error.from_normal(f"{data_root}/gravity/monthly_normals/ITSG-Grace2018_n96_2007-03.snx", scaling_factor = 0.9330416388987962)  # EXPENSIVE!! ~1 min

[2]:

<gfeatpy.gravity.SphericalHarmonicsCovariance at 0x7502ded06170>

[3]:

# Plot EWH commission error
plotting.synthesis(monthly_error, 180, 90, EquivalentWaterHeight(0))
plt.show()

Warning: Number of longitude nodes increased to 192 reach full SH spectrum during FFT synthesis over parallels.
../../_images/notebooks_gravity-field-data_normals_4_1.png 
[4]:

# Plot EWH + Gaussian spatial smoothing filter r=750 km
plotting.synthesis(monthly_error, 180, 90, EquivalentWaterHeight(750e3))
plt.show()

Warning: Number of longitude nodes increased to 192 reach full SH spectrum during FFT synthesis over parallels.
../../_images/notebooks_gravity-field-data_normals_5_1.png

Resonant case

[5]:

# Load monthly normal matrix
monthly_error = SphericalHarmonicsCovariance(96)
monthly_error.from_normal(f"{data_root}/gravity/monthly_normals/ITSG-Grace2018_n96_2004-09.snx", scaling_factor = 1.0)  # EXPENSIVE!! ~1 min # scale factor incorrect!!

[5]:

<gfeatpy.gravity.SphericalHarmonicsCovariance at 0x7502ddc26cb0>

[6]:

# Plot EWH
plotting.synthesis(monthly_error, 180, 90, EquivalentWaterHeight(0))
plt.show()

Warning: Number of longitude nodes increased to 192 reach full SH spectrum during FFT synthesis over parallels.
../../_images/notebooks_gravity-field-data_normals_8_1.png 
[7]:

# Plot EWH + Gaussian spatial smoothing filter r=750 km
plotting.synthesis(monthly_error, 180, 90, EquivalentWaterHeight(750e3))
plt.show()

Warning: Number of longitude nodes increased to 192 reach full SH spectrum during FFT synthesis over parallels.
../../_images/notebooks_gravity-field-data_normals_9_1.png