Scattering Truncation¶

Particula-beta Index / Particula Beta / Data / Process / Scattering Truncation

Auto-generated documentation for particula_beta.data.process.scattering_truncation module.

correction_for_distribution¶

Show source in scattering_truncation.py:245

Correction for a size distribution of particles.

Calculates the correction factor for scattering measurements due to truncation effects in aerosol size distribution measurements. This correction factor is used to adjust the measured scattering coefficient, accounting for the limited angular range of the instrument.

Arguments¶

m_sphere - The complex or real refractive index of the particles.
wavelength - The wavelength of the incident light in nanometers (nm).
diameter_sizes - An array of particle diameters in nanometers (nm) corresponding to the size distribution.
number_per_cm3 - An array of particle number concentrations (#/cm^3) for each diameter in the size distribution.
discretize - If True, the calculation will use discretized values for the refractive index, wavelength, and diameters to potentially improve computation performance. Default is True.

Returns¶

Array: The correction factor for scattering measurements. This factor is dimensionless and is used to correct the measured scattering coefficient for truncation effects, calculated as the ratio of the ideal (full angular range) to truncated scattering coefficient.

Examples¶

b_sca_corrected = b_sca_measured * bsca_correction

Signature¶

def correction_for_distribution(
    m_sphere: Union[complex, float],
    wavelength: float,
    diameter_sizes: NDArray[np.float64],
    number_per_cm3: NDArray[np.float64],
    discretize: bool = True,
) -> Union[float, np.float64]: ...

correction_for_humidified¶

Show source in scattering_truncation.py:313

Truncation Correction for humidified aerosol measurements.

Calculates the scattering correction for humidified aerosol measurements, accounting for water uptake by adjusting the aerosol's refractive index. This function requires the kappa values for the particles, which describe their hygroscopic growth.

Arguments¶

kappa - Hygroscopicity parameter kappa, indicating the water uptake capability of the particles.
number_per_cm3 - Number concentration of particles per cubic centimeter (#/cm³) for each size bin.
diameter - Array of particle diameters in nanometers (nm).
water_activity_sizer - Water activity (relative humidity/100) of the air sample used for sizing.
water_activity_sample - Water activity (relative humidity/100) of the air sample in optical measurements.
refractive_index_dry - Refractive index of the dry particles. Default is 1.45.
water_refractive_index - Refractive index of water. Default is 1.33.
wavelength - Wavelength of the incident light in nanometers (nm). Default is 450.
discretize - If True, calculation uses discretized values for refractive index, wavelength, and diameters to improve performance. Default is True.

Returns¶

np.float64: A numpy array of scattering correction factors for each particle size in the distribution, to be applied to measured backscatter coefficients to account for truncation effects due to humidity.

Signature¶

def correction_for_humidified(
    kappa: Union[float, np.float64],
    number_per_cm3: NDArray[np.float64],
    diameter: NDArray[np.float64],
    water_activity_sizer: np.float64,
    water_activity_sample: np.float64,
    refractive_index_dry: Union[complex, float] = 1.45,
    water_refractive_index: Union[complex, float] = 1.33,
    wavelength: float = 450,
    discretize: bool = True,
) -> np.float64: ...

correction_for_humidified_looped¶

Show source in scattering_truncation.py:387

Looped correction for humidified aerosol measurements.

Corrects scattering measurements for aerosol particles to account for truncation errors in CAPS instrument. This correction is vital for accurate representation of particle scattering properties under different humidity conditions. The function iterates over time-indexed measurements, calculating corrections based on input parameters reflecting the particles' physical and chemical characteristics.

Arguments¶

kappa - Hygroscopicity parameter array for the aerosol particles, indicating water uptake ability.
number_per_cm3 - Time-indexed number concentration of particles in #/cm³ for each size.
diameter - Particle diameters, crucial for calculating scattering effects.
water_activity_sizer - Water activity measured by the sizing instrument, indicating relative humidity.
water_activity_sample - Sample water activity, corresponding to the ambient conditions during measurement.
refractive_index_dry - Refractive index of the dry particles, affecting their scattering behavior. Default is 1.45.
water_refractive_index - Refractive index of water, important for calculations involving humidified conditions. Default is 1.33.
wavelength - Wavelength of the incident light in nanometers, which influences scattering intensity. Default is 450.
discretize - If set to True, performs discretized calculations for potentially improved computational performance. Default is True.

Returns¶

An array of corrected scattering multipliers for each time index, accounting for aerosol particle size, composition, and environmental conditions.

Notes¶

The correction process includes data nan checks for missing values, ensuring robust and reliable correction outcomes.

Signature¶

def correction_for_humidified_looped(
    kappa: NDArray[np.float64],
    number_per_cm3: NDArray[np.float64],
    diameter: NDArray[np.float64],
    water_activity_sizer: NDArray[np.float64],
    water_activity_sample: NDArray[np.float64],
    refractive_index_dry: Union[complex, float] = 1.45,
    water_refractive_index: Union[complex, float] = 1.33,
    wavelength: float = 450,
    discretize: bool = True,
) -> NDArray[np.float64]: ...

get_truncated_scattering¶

Show source in scattering_truncation.py:17

Extracts the truncated scattering intensity and corresponding angles based on the given truncation angles.

Arguments¶

su - The scattering intensity for unpolarized light as a function of angle.
theta - The array of angles corresponding to the scattering intensity measurements.
theta1 - The lower bound of the angle range for truncation in radians.
theta2 - The upper bound of the angle range for truncation in radians.

Returns¶

Tuple (np.ndarray, np.ndarray): A tuple containing the truncated scattering intensity and the corresponding angles within the truncated range.

Signature¶

def get_truncated_scattering(
    scattering_unpolarized: np.ndarray, theta: np.ndarray, theta1: float, theta2: float
) -> Tuple[np.ndarray, np.ndarray]: ...

trunc_mono¶

Show source in scattering_truncation.py:47

Truncation correction for monodisperse aerosol particle.

Calculates the single scattering albedo (SSA) correction due to truncation for monodisperse aerosol measurements using the CAPS-PM-SSA instrument. The correction accounts for the incomplete angular range of scattering measurements due to the instrument's geometry.

Arguments¶

m_sphere - Complex or real refractive index of the aerosol.
wavelength - Wavelength of light in nanometers used in the CAPS instrument.
diameter - Diameter of the monodisperse aerosol in nanometers.
full_output - If True, additional details about the calculation are returned, including z-axis values, angles of integration, and both truncated and ideal scattering efficiencies. calibrated_trunc : bool, optional If True, applies a numberical calibration factor to the truncation correction, so 150 is 1. Default is True. discretize : bool, optional If True, discretizes the input parameters for potentially improved stability/performance in scattering function calculations. Can not be done for full_output=True

Returns¶

Tuple: If fullOutput is False, returns only the truncation correction factor. If fullOutput is True, returns a tuple containing the truncation correction factor, z-axis positions, truncated scattering efficiency, ideal scattering efficiency, forward scattering angle, and backward scattering angle.

Signature¶

@lru_cache(maxsize=100000)
def trunc_mono(
    m_sphere: Union[complex, float],
    wavelength: float,
    diameter: float,
    full_output: bool = False,
    calibrated_trunc: bool = True,
    discretize: bool = True,
) -> Union[
    float, Tuple[float, np.ndarray, np.ndarray, np.ndarray, np.ndarray, np.ndarray]
]: ...

truncation_for_diameters¶

Show source in scattering_truncation.py:191

Truncation correction for an array of particle diameters.

Calculates the truncation correction for an array of particle diameters given a specific refractive index and wavelength. This function is particularly useful for aerosol optical property measurements where truncation effects due to instrument geometry need to be accounted for.

Arguments¶

m_sphere - The complex or real refractive index of the particles.
wavelength - The wavelength of the incident light in nanometers (nm).
diameter_sizes - An array of particle diameters in nanometers (nm) for which the truncation correction will be calculated.
discretize - A flag indicating whether to discretize the input parameters for potentially improved calculation performance. Default is True.
calibrated_trunc - If True, applies a numberical calibration factor to the truncation correction, so 150 is 1. Default is True.

Returns¶

An array of truncation corrections corresponding to the input array of particle diameters.

Signature¶

def truncation_for_diameters(
    m_sphere: Union[complex, float],
    wavelength: float,
    diameter_sizes: NDArray[np.float64],
    discretize: bool = True,
    calibrated_trunc: bool = True,
) -> NDArray[np.float64]: ...