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.
SAGE III on ISS
Clouds play a major role in determining the planet's solar and longwave energy balance and, thus, are important in governing the Earth's climate. will provide measurements of mid and high level clouds including thin or "sub-visual" clouds that are not detectable by nadir-viewing passive remote sensors. These observations are important because while low clouds primarily reflect incoming solar radiation back into space (acting to cool the planet), mid and high level clouds enhance the "greenhouse" effect by trapping infrared radiation (acting to warm the planet). Also, the presence of thin cloud near the tropopause may play a significant role in heterogeneous chemical processes that lead to ozone destruction in mid-latitudes.