1 bodhaine
bodhaine
Rayleigh Optical Depth calculation from Bodhaine, 99
rod(lam, co2, lat, z, P)
1.1 Functions
| Name | Description |
|---|---|
| FN2 | depolarisation factor of N2 |
| FO2 | depolarisation factor of O2 |
| Fair | depolarisation factor of air for CO2 |
| column_number_density | Calculate column number density of air molecules (molecules/cm²). |
| g | gravity acceleration at altitude z |
| g0 | gravity acceleration at the ground |
| ma | molecular volume |
| n300 | index of refraction of dry air (300 ppm CO2) |
| n_air | index of refraction of dry air |
| raycrs | Rayleigh cross section |
| rod | Rayleigh optical depth calculation for Bodhaine, 1999. |
1.1.1 FN2
bodhaine.FN2(lam)depolarisation factor of N2 lam : um
1.1.2 FO2
bodhaine.FO2(lam)depolarisation factor of O2 lam : um
1.1.3 Fair
bodhaine.Fair(lam, co2)depolarisation factor of air for CO2 lam : um co2 : ppm
1.1.4 column_number_density
bodhaine.column_number_density(
co2=400.0,
lat=45.0,
z=0.0,
P=1013.25,
pressure='surface',
)Calculate column number density of air molecules (molecules/cm²).
1.1.4.1 Parameters
| Name | Type | Description | Default |
|---|---|---|---|
| co2 | float | CO2 concentration in ppm. Default 400.0. | 400.0 |
| lat | float | Latitude in degrees. Default 45.0. | 45.0 |
| z | float | Altitude in meters. Default 0.0. | 0.0 |
| P | float | Reference pressure in hPa. Default 1013.25. | 1013.25 |
| pressure | Literal['sea-level', 'surface'] | Pressure reference type. Default “surface”. | 'surface' |
1.1.4.2 Returns
| Name | Type | Description |
|---|---|---|
| float | Column number density of air molecules. |
1.1.5 g
bodhaine.g(lat, z)gravity acceleration at altitude z lat : deg (scalar) z : m
1.1.6 g0
bodhaine.g0(lat)gravity acceleration at the ground lat : deg
1.1.7 ma
bodhaine.ma(co2)molecular volume co2 : ppm
1.1.8 n300
bodhaine.n300(lam)index of refraction of dry air (300 ppm CO2) lam : um
1.1.9 n_air
bodhaine.n_air(lam, co2)index of refraction of dry air lam : um co2 : ppm
1.1.10 raycrs
bodhaine.raycrs(lam, co2=400.0)Rayleigh cross section lam : um co2 : ppm
1.1.11 rod
bodhaine.rod(lam, co2=400.0, lat=45.0, z=0.0, P=1013.25, pressure='surface')Rayleigh optical depth calculation for Bodhaine, 1999.
Calculates the Rayleigh optical depth for dry air at a given wavelength, accounting for CO2 concentration, latitude, altitude, and pressure.
1.1.11.1 Parameters
| Name | Type | Description | Default |
|---|---|---|---|
| lam | float | Wavelength in micrometers (um). | required |
| co2 | float | CO2 concentration in ppm. Default is 400.0. | 400.0 |
| lat | float | Latitude in degrees. Default is 45.0. | 45.0 |
| z | float | Altitude in meters. Default is 0.0. | 0.0 |
| P | float | Reference pressure in hPa. Default is 1013.25. | 1013.25 |
| pressure | Literal['sea-level', 'surface'] | Pressure reference type. Default is “surface”. | 'surface' |
1.1.11.2 Returns
| Name | Type | Description |
|---|---|---|
| float | Rayleigh optical depth. |
1.1.11.3 Notes
This implementation follows the methodology described in: Bodhaine, B. A., Wood, N. T., Dutton, E. G., & Slusser, J. R. (1999). “Rayleigh optical depth calculations for atmospheric research”. Atmospheric Environment, 33(15), 2235-2248.
1.1.11.4 Example
rod(0.4, 400., 45., 0., 1013.25)