Description
Return plane-parallel airmass and slant optical depth.
Atmospheric optical and radiation quantities distinguish spectral density, integrated flux, solid-angle response and reporting codes. A local attenuation factor, bin contribution or coverage bound requires compatible geometry and definitions rather than establishing a complete radiative transfer or observed cloud state.
Return plane-parallel airmass and slant optical depth.
When to use this tool
Use Optical Path Airmass Factor when checking the stated optical, radiometric, cloud-code or coverage convention.
How to use the tool and how it works
- Enter zenithRadians, verticalOpticalDepth. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read airmass, slantOpticalDepth. Use the output convention below.
Return plane-parallel airmass and slant optical depth. Require zenithRadians in [0,pi/2) and verticalOpticalDepth >= 0; airmass = 1/cos(zenith), slantDepth = vertical*airmass.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| zenithRadians | Zenith Radians | Required. Finite number; minimum 0. |
| verticalOpticalDepth | Vertical Optical Depth | Required. Finite number; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| airmass | Airmass | Required. Finite number. |
| slantOpticalDepth | Slant Optical Depth | Required. Finite number. |
{
"input": {
"zenithRadians": 0,
"verticalOpticalDepth": 0.2
},
"output": {
"airmass": 1,
"slantOpticalDepth": 0.2
}
}Limitations and assumptions
- This secant model omits curvature and becomes unreliable near the horizon; no actual atmospheric transmission is inferred without additional modeling.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use the source-specific observation code table and an appropriate calibrated spectral/atmospheric model for actual cloud or radiative interpretation.
References
Similar or alternative tools
- Aerosol Optical Depth Slant Factor
Return plane-parallel slant aerosol optical depth.
- Rayleigh Scattering Wavelength Ratio
Return Rayleigh wavelength scaling.