import pandas as pd
import numpy as np
[docs]
def load_mie_file(filename):
"""
Loads the Mie parameters from a file.
Parameters
----------
filename: str
The name of the file storing the Mie scattering parameters
Returns
-------
my_df: xarray.Dataset
The xarray Dataset storing the Mie parameters, including
descriptive metadata.
"""
my_df = pd.read_csv(filename, delim_whitespace=True,
names=["wavelength", "p_diam", "size_parameter", "compre_real",
"compre_im", "scat_p", "alpha_p", "beta_p", "scat_eff",
"ext_eff", "backscat_eff"])
my_df["alpha_p"] = my_df["alpha_p"] * 1e-12
my_df["beta_p"] = my_df["beta_p"] * 1e-12 / (4 * np.pi)
my_df["scat_p"] = my_df["scat_p"] * 1e-12
my_df["p_diam"] = 2e-6 * my_df["p_diam"]
my_df["backscat_eff"] = my_df["backscat_eff"] / (4 * np.pi)
my_df = my_df.to_xarray()
my_df["wavelength"].attrs["units"] = "microns"
my_df["wavelength"].attrs["long_name"] = "Wavelength of beam"
my_df["wavelength"].attrs["standard_name"] = "wavelength"
my_df["p_diam"].attrs["units"] = "meters"
my_df["p_diam"].attrs["long_name"] = "Diameter of particle"
my_df['p_diam'].attrs["standard_name"] = "Diameter"
my_df["size_parameter"].attrs["units"] = "1"
my_df["size_parameter"].attrs["long_name"] = "Size parameter (pi*diameter / wavelength)"
my_df['size_parameter'].attrs["standard_name"] = "Size parameter"
my_df["compre_real"].attrs["units"] = "1"
my_df["compre_real"].attrs["long_name"] = ("Complex refractive index of the sphere divided " +
"by the real index of the medium (real part)")
my_df['compre_real'].attrs["standard_name"] = "Complex_over_real_Re"
my_df["compre_im"].attrs["units"] = "1"
my_df["compre_im"].attrs["long_name"] = ("Complex refractive index of the sphere divided " +
"by the real index of the medium (imaginary part)")
my_df['compre_im'].attrs["standard_name"] = "Complex_over_real_Im"
my_df["scat_p"].attrs["units"] = "microns^2"
my_df["scat_p"].attrs["long_name"] = "scattering cross section"
my_df["scat_p"].attrs["standard_name"] = "Scat_cross_section"
my_df["beta_p"].attrs["units"] = "meters^2"
my_df["beta_p"].attrs["long_name"] = "Back scattering cross section"
my_df["beta_p"].attrs["standard_name"] = "Scat_cross_section_back"
my_df["alpha_p"].attrs["units"] = "meters^2"
my_df["alpha_p"].attrs["long_name"] = "Extinction cross section"
my_df["alpha_p"].attrs["standard_name"] = "Ext_cross_section"
my_df["scat_eff"].attrs["units"] = "1"
my_df["scat_eff"].attrs["long_name"] = "scattering efficiency"
my_df["scat_eff"].attrs["standard_name"] = "Scattering_efficiency"
my_df["ext_eff"].attrs["units"] = "1"
my_df["ext_eff"].attrs["long_name"] = "Extinction efficiency"
my_df["ext_eff"].attrs["standard_name"] = "Extinction_efficiency"
my_df["backscat_eff"].attrs["units"] = "sr^-1"
my_df["backscat_eff"].attrs["long_name"] = "Backscattering efficiency"
my_df["backscat_eff"].attrs["standard_name"] = "Backscattering_efficiency"
return my_df