Umbra

Umbra
That part of the shadow cast by the Earth or the Moon within which the Sun is completely hidden.
Unsettled ...

Umbra Central dark area of a sunspot.
Universal Coordinated Time (UTC) A worldwide time reference used for synchronizing weather observations; the time at 0 degrees longitude, the prime meridian.

Delta: A complex magnetic configuration of a solar sunspot group consisting of opposite polarity umbrae within the same penumbra.

A: A small single unipolar sunspot or very small group of spots without penumbra.
B: Bipolar sunspot group with no penumbra.
C: An elongated bipolar sunspot group. One sunspot must have penumbra.

sunspot A relatively dark, sharply defined region on the solar disk, marked by an umbra approximately 2000K cooler than the effective photospheric temperature, surrounded by a less dark but also sharply bounded penumbra.

Light BridgeIn solar-terrestrial terms, it is observed in white light, a bright tongue or streaks penetra- ting or crossing sunspot umbrae.

Umbra: Central dark spot of a "Sunspot" having a temperature of about 4,000 Degs. Kelvin.
Unlimeted Ceiling: Clear skies or scattered cloud conditions.
Updraft: Rising air.
Upper Air Chart: Weather maps depicting the upper atmosphere. Ex.

In solar-terrestrial terms, the dark core or cores (umbrae) in a sunspot with penumbra, or a sunspot lacking penumbra.
NOAA National Weather Service - Cite This Source - This Definition ...

In solar-terrestrial terms, the sunspot area that may surround the darker umbra or umbrae. It consists of linear bright and dark elements radial from the sunspot umbra.
Perched Groundwater ...

See also: Radiation, Temperature, Air, Thunderstorm, Thunder