chaosmagpy.chaos.load_CovObs_txtfile

chaosmagpy.chaos.load_CovObs_txtfile(filepath, name=None)[source]

Load the ensemble mean of the internal model from the COV-OBS txt-file in spline format.

Parameters
filepathstr

Path to spline-formatted txt-file (not part of ChaosMagPy).

namestr, optional

User defined name of the model. Defaults to the filename without the file extension.

Returns
modelBaseModel

Class BaseModel instance.

References

For details on the COV-OBS model (COV-OBS.x2), see the original publication:

Huder, L., Gillet, N., Finlay, C. C., Hammer, M. D. and H. Tchoungui (2020), “COV-OBS.x2: 180 yr of geomagnetic field evolution from ground-based and satellite observations”, Earth, Planets and Space.

Examples

Load the ensemble mean internal model and plot the degree-1 secular variation. Here, the model parameter file, e.g. “COV-OBS.x2-int”, is in the current working directory.

import chaosmagpy as cp
import matplotlib.pyplot as plt
import numpy as np

model = cp.load_CovObs_txtfile('COV-OBS.x2-int')  # load model txt-file

fig, ax = plt.subplots(1, 1, figsize=(10, 6))

# sample model timespan
time = np.linspace(1840., 2020., 1000)  # decimal years
mjd = cp.data_utils.dyear_to_mjd(time, leap_year=False)

coeffs = model.synth_coeffs(mjd, nmax=1, deriv=1)

ax.plot(cp.data_utils.timestamp(time), coeffs)
ax.set_title(model.name)
ax.set_xlabel('Time (years)')
ax.set_ylabel('nT/yr')

ax.legend(['$g_1^0$', '$g_1^1$', '$h_1^1$'])

plt.tight_layout()
plt.show()