A few strong to marginally severe thunderstorms are possible across the Southeast U.S. Friday. A Marginal Risk (Level 1 of 5) outlook has been issued. Strong winds and hail will be the main threats. Elevated to locally critical fire weather conditions will persist across south-central Colorado today due to dry conditions and gusty winds. Read More >
X-Band
A frequency band of microwave radiation in which radars operate.
X-Ray Background
In solar-terrestrial terms, a daily average background X-ray flux in the 1 to 8 angstrom range. It is a midday minimum designed to reduce the effects of flares.
X-Ray Burst
In solar-terrestrial terms, a temporary enhancement of the X-ray emission of the sun. The time-intensity profile of soft X-ray bursts is similar to that of the H-alpha profile of an associated flare.
X-Ray Flare Class
In solar-terrestrial terms, rank of a flare based on its X-ray energy output. Flares are classified by the order of magnitude of the peak burst intensity (I) measured at the earth in the 1 to 8 angstrom band as follows:
|
Class |
Intensity (in Watts/m2) |
|
B |
I < 10-6 |
|
C |
10-6 <= I < 10-5 |
|
M |
10-5 <= I < 10-4 |
|
X |
I >= 10-4 |
X-Rays
Very energetic electromagnetic radiation with wavelengths intermediate between 0.01 and 10 nanometers (0.1-100 Angstroms) or between gamma rays and ultraviolet radiation. Essentially all X-Rays from space are absorbed in the Earth's upper atmosphere.
XBT
Expendable Bathythermograph
XCITED
Excited
XCPT
Expecting
XPC
Expect
XSEC
Cross Section
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