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.
Kate Marvel
Marvel's current research centers on climate modeling to better predict how much the Earth's temperature will rise rise in the future. This work led Marvel to investigate the effects of cloud cover on modeling rising temperatures, which has proved an important variable in climate models. Clouds can play a double-edged role in mitigating or amplifying the rate of global warming. On one hand, clouds reflect solar energy back into space, serving to cool the planet; on the other, clouds can trap the planet's heat and radiate back onto Earth's surface. While computer models have difficulty simulating the changing patterns of cloud cover, improved satellite data can begin to fill in the gaps.