What is the wavelength of water vapor?
Water vapor absorbs and reradiates electromagnetic radiation in various wavelength bands, most notably the infrared 6-7 micron band. Such infrared radiation — emitted by the Earth/atmosphere and intercepted by satellites — is the basis for remote sensing of tropospheric water vapor.
How do you calculate atmospheric water vapor?
Here, we show various measures of the variable atmospheric water vapor content. e is vapor pressure Rv = R∗/Mv = 461.5Jkg−1K−1 and Mv = 18.01gmol−1, ϵ = Mv/Md = 0.622. The vapor pressure is the partial pressure of the water vapor. where es is in Pascals and T is in Celsius.
What is the chemical formula for water vapor?
Water vapor
| Water vapor (H2O) | |
|---|---|
| Molecular formula | H2O |
| Molar mass | 18.01528(33) g/mol |
| Melting point | 0.00 °C (273.15 K) |
| Boiling point | 99.98 °C (373.13 K) |
How do satellites detect water vapor?
Satellite instruments such as those on GOES can detect water vapor in the infrared spectrum between the 6.55 to 7.3 micrometer wavelength ranges. Water vapor seen at these infrared wavelengths is in the upper and middle levels of the troposphere, where the winds are ruled by large-scale air masses.
How is the radiance of water vapor measured?
One way to qualitatively interpret water-vapor imagery is to say that it approximates the relative humidity of the midtroposphere. Consider a bright area and a dark area in a water-vapor image. In the bright area, the satellite measures less radiance than in the dark area.
How are radiation values converted to temperature on a satellite?
The satellite radiometer therefore captures a grid of radiation intensity values at 10.7 microns. Next, these radiation values are converted into temperatures using equations derived from Planck’s Law and Kirchhoff’s Law.
Why are the water vapor channels called that?
The water-vapor channels are so named because the satellite measures radiation in water-vapor absorption bands. Several wavelengths can be used, but the most common is centered around 6.7 μm.
What is the mixing ratio of water vapor?
The water vapor mixing ratio is defined as the ratio of the mass of water vapor to the mass of dry air in a given volume. The mixing ratio is conserved in atmospheric processes that do not involve condensation or evaporation, and thus serves well as a tracer of the movement of air parcels in the atmosphere.
