Broadcast range
The local terrain can also play a major role in limiting broadcast range. Mountain ranges block FM broadcasts, AM broadcasts, and TV broadcasts, and other signals in the VHF and especially UHF ranges, respectively. This terrain shielding occurs when the line of sight is blocked by something through which the radio waves cannot pass, particularly stone. At times this may be moot due to weather, such as when the tall cumulonimbus clouds of a squall line of thunderstorms reflect the signal over the top, like an extremely tall radio tower. Conversely, heavy rain may attenuate the range of even local stations. ATSC digital television is affected by wind and trees (even if not surrounding the transmitter or receiver locations), apparently related to its use of 8VSB modulation instead of COFDM.
Outgoing longwave radiation
Longwave radiation typically refers to radiation in the spectral region from 3 to 100 microns. In the Earth’s climate system, longwave radiation involves processes of absorption, scattering, and emissions from atmospheric gases, aerosols, clouds and the surface. Measuring outgoing longwave radiation at the top of atmosphere and downwelling longwave radiation at the surface is important for understanding how much radiative energy is kept in our climate system, how much reaches and warms the surface, and how the energy in the atmosphere is distributed to affect developments of clouds.