Downwelling Longwave Clear Sky Parametrization Calculator
Clear-sky calibrated emissivityσT⁴ downwelling model; caller independent same-band humidity calibration, not surface emitted flux or universal emissivity. Caller independently establishes matching units, evidence, method edition and applicability; output is not compliance, diagnosis, work-safety approval, geological identity or validated hazard prediction.
Description
An effective-emissivity longwave model scales blackbody emission by an atmospheric emissivity.
An effective-emissivity longwave model scales blackbody emission by an atmospheric emissivity.1
Temperature must be absolute, and the chosen emissivity must suit the clear-sky conditions being modeled.
When to use Downwelling Longwave Clear Sky Parametrization Calculator
Use this tool to calculate or review the supplied observations under the stated rules. Establish the observation method, units, averaging period and applicable reference or calibration.
How to use Downwelling Longwave Clear Sky Parametrization Calculator and understand its results
- Establish the observation method, units, averaging period and applicable reference or calibration.
- Enter observedAirTemperatureK, independentlyCalibratedAtmosphericEmissivity, callerStefanBoltzmannWM2K4, using the field meanings and rules below, then run the tool.
- Read conditionalClearSkyDownwellingWM2, using the output meanings and calculation rules below.
- Correct any reported input issue and run again. Before using a successful result, check the stated units, signs, reference scope and observation coverage.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| observedAirTemperatureK | Observed air temperature k | number | Required |
| independentlyCalibratedAtmosphericEmissivity | Independently calibrated atmospheric emissivity | number | Required |
| callerStefanBoltzmannWM2K4 | Caller stefan boltzmann w m2 k4 | number | Required |
Require absolute air temperature and the caller Stefan–Boltzmann coefficient strictly positive, with emissivity in [0,1]. Calculate emissivity times the coefficient times the fourth power of temperature. Nonfinite results are rejected.
downwellingWM2=emissivity×sigmaWM2K4×temperatureK^4 Use the matching field units and the exact boundary, ordering and reference rules above.
| Output field | Meaning | Value type |
|---|---|---|
| conditionalClearSkyDownwellingWM2 | Conditional clear sky downwelling w m2 | number |
{
"input": {
"observedAirTemperatureK": 300,
"independentlyCalibratedAtmosphericEmissivity": 0.8,
"callerStefanBoltzmannWM2K4": 5.670374419e-8
},
"output": {
"conditionalClearSkyDownwellingWM2": 367.44026235120003
}
}Limitations and assumptions
This does not calibrate emissivity from humidity, cloud observations or radiation measurements, and it does not model all-sky emission or net radiative balance.
Missing required fields, unknown fields, wrong types and violated rules return input issues. Numeric values and outputs must be finite.
Alternative or Complementary methods
For a related step, use Effective Atmospheric Emissivity Lookup: Effective atmospheric emissivity represents longwave emission relative to a chosen thermal reference. For a complementary comparison, use Daily Clear Sky Insolation Estimate Calculator: Integrating irradiance over time gives radiant energy per area.
References
Similar or alternative tools
- Effective Atmospheric Emissivity Lookup
Effective atmospheric emissivity represents longwave emission relative to a chosen thermal reference.
- Daily Clear Sky Insolation Estimate Calculator
Integrating irradiance over time gives radiant energy per area.