Visibility Measurement

• visibility is as far as you can see a large contrasting object
• visibility sensor - can see scattered light when there is something to scatter off of

Cloud Height Measurement

• called ceiling
• laser ceiliometer - time for light to travel to cloud and back

Solar Radiation Measurement

• called pyranometer
• difference in temperature between black and white surfaces

Rawinsonde

• carried aloft with a balloon
• measures temperature, humidity, pressure and wind

Rayleigh Scattering:

• scattering object much smaller than light wavelength - (off air molecules)
• amount of scattering proportional to one over the 4th power of wavelength
• short wavelengths scatter much more than long
• blue skys and red sunsets

Mie Scattering:

• object size similar to wavelength
• scatter all wavelengths the same
• white clouds and grey skys (dust, pollution)

Satellites

• Geostationary Satellites - stay over one location on equator
• visible image - higher resolution
• infrared image - high temperatures dark and low ones light
• water vapor band image - shows high concentrations of water vapor
• Polar Orbit Satellites
• covers the poles
• more detailed coverage