Brightness temperature
The raw quantity a microwave or infrared sensor measures: how much energy a surface emits, expressed as the temperature a perfect emitter would need to give off that much. It is not quite the real physical temperature.
Brightness temperature
The raw quantity a microwave or infrared sensor measures: how much energy a surface emits, expressed as the temperature a perfect emitter would need to give off that much. It is not quite the real physical temperature.
Why it matters
Brightness temperature is the building block for retrieving soil moisture, sea ice, snow, and sea surface temperature — scientists convert it into those products by accounting for how efficiently each surface emits energy.
Where you’ll meet it
- SMAP records brightness temperature in its lower-level products before it is turned into soil moisture.
- AMSR2 reports brightness temperature across many microwave channels, the starting point for its ocean and cryosphere products.
- GPM’s GMI measures brightness temperature to infer rainfall.
In plain terms
It’s like guessing how hot a stove burner is by how brightly it glows — the glow tells you a temperature, but a dull-surfaced burner can run hot while looking dim.