neptoon.corrections.theory

calibration_functions

Classes:

• Schroen2017

Functions:

• horizontal_weighting
• horizontal_weighting_approx
• calculate_measurement_depth
• vertical_weighting
• rescale_distance
• calculate_footprint_radius
• calculate_footprint_volume

This module contains functions related to calibration steps

Schroen2017

horizontal_weighting staticmethod

horizontal_weighting(distance=1, volumetric_soil_moisture=0.1, abs_air_humidity=5.0, normalize=False)

W_r is the radial weighting function for point measurements taken in the footprint of the sensor.

Parameters:

Name	Type	Description	Default
distance	float or array or Series	Rescaled distance from sensor in meters (m). Referred to as r in Schroen et al., (2017). See: Schroen2017.radius_rescale()	1
volumetric_soil_moisture	float	Soil Moisture from 0.02 to 0.50 in m3/m3. Referred to as y in Schroen et al., (2017)	0.1
abs_air_humidity	float	Absolute air humidity in g/m^3. Referred to as x in Schroen et al., (2017)	5.0
normalze	bool	Normalize the weights relative to the sum of weights	required

Returns:

Name	Type	Description
weight	float	The weighting to apply to the sample.

horizontal_weighting_approx staticmethod

horizontal_weighting_approx(distance=1, normalize=False)

W_r_approx is an approximation of the radial weighting function for point measurements taken in the footprint of the sensor.

Parameters:

Name	Type	Description	Default
distance	float or array or Series	Rescaled distance from sensor in meters (m). Referred to as r in Schroen et al., (2017). See: Schroen2017.radius_rescale()	1
normalize	bool	Normalize the weights relative to the sum of weights	False

Returns:

Name	Type	Description
weight	float	The weighting to apply to the sample.

calculate_measurement_depth staticmethod

calculate_measurement_depth(distance, bulk_density, volumetric_soil_moisture)

Calculates the depth of sensor measurement (taken as the depth from which 86% of neutrons originate)

Parameters:

Name	Type	Description	Default
distance	float	Rescaled distance from sensor in meters (m). Referred to as r in Schroen et al., (2017). See Schroen2017funcs.radius_rescale()	required
bulk_density	float	Dry soil bulk density of the soil (g/cm^3)	required
volumetric_soil_moisture	float	Volumetric soil moisture from 0.02 to 0.50 in cubic centimeter per cubic centimeter (m3/m3)	required

Returns:

Name	Type	Description
D86	float	The depth of the sensor measurement in centimeters (cm)

vertical_weighting staticmethod

vertical_weighting(depth, distance=1.0, bulk_density=1.6, volumetric_soil_moisture=0.1)

Wd Weighting function to be applied on samples to calculate weighted impact of soil samples based on depth.

Parameters:

Name	Type	Description	Default
depth	float	Depth of sample in centimeters (cm)	required
distance	float	Rescaled distance from sensor in meters (m). Referred to as r in Schroen et al., (2017). See Schroen2017funcs.radius_rescale()	1.0
bulk_density	float	Dry soil bulk density in grams per cubic centimeter (g/cm^3)	1.6
volumetric_soil_moisture	float	Soil Moisture from 0.02 to 0.50 in cubic centimeter per cubic centimeter (cm3/cm3)	0.1

Returns:

Name	Type	Description
weight	float	The weight to give the sample.

rescale_distance staticmethod

rescale_distance(distance_from_sensor, atmospheric_pressure=1013.25, height_veg=0, volumetric_soil_moisture=0.1)

Rescales the distance to account for influences from atmospheric pressure, vegetation and antecedant soil moisture.

Parameters:

Name	Type	Description	Default
distance_from_sensor	float	Distance from the sensor in meters (m)	required
pressure	float	Pressure at the site in hectopascals (hPa)	required
height_veg	float	Height of vegetation during calibration period in meters (m)	0
volumetric_soil_moisture	float	Volumetric soil moisture from 0.02 to 0.50 in cubic centimeters per cubic centimeters (cm3/cm3)	0.1

Returns:

Name	Type	Description
rescaled_radius	float	The adjusted radius to use in future calculations.

calculate_footprint_radius staticmethod

calculate_footprint_radius(volumetric_soil_moisture=0.1, abs_air_humidity=5.0, atmospheric_pressure=None)

Parameters:

Name	Type	Description	Default
volumetric_soil_moisture	float	Soil Moisture from 0.02 to 0.50 in m3/m3. Referred to as y in Schroen et al., (2017)	0.1
abs_air_humidity	float	Absolute air humidity from 0.1 to 0.50 in g/m^3. Referred to as x in Schroen et al., (2017)	5.0
atmospheric_pressure	float	Atmospheric pressure in hectopascals	None

Returns:

Name	Type	Description
R86	float	Footprint radius in meters

calculate_footprint_volume

calculate_footprint_volume(D86_1m, soil_moisture, bulk_density, footprint_radius)

Footprint volume in m³

Parameters:

Name	Type	Description	Default
D86_1m	float or array - like	Measurement depth at 1 m distance	required
soil_moisture	float or array - like	Soil moisture in m³/m³	required
bulk_density	float or array - like	Bulk density	required
footprint_radius	float or array - like	Footprint radius in meters	required

Returns:

Type	Description
V86	Footprint volume in m³