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TERM
DESCRIPTION
INCHES OF
MERCURY (inHg)
This is the common unit of measurement for air
pressure in the United States. It refers to the length of
a standard column of mercury (a liquid metal) that
can be pushed up by the ambient air pressure.
Standard pressure is approximately 29.92 inHg
KNOTS (kn)
One knot is equivalent to one nautical mile and is
sometimes used to indicate wind speed.
LCD
An acronym for “Liquid Crystal Display.” This is a
common type of display screen used in televisions,
computers, watches, and digital clocks.
LUX (lx)
The unit of illuminance (
a measure of the intensity of
illumination on a surface
) as used in the SI system.
MILLIBAR (mb)
See HECTOPASCALS.
MM OF MERCURY
(mmHg)
This is similar to inches of mercury, except
expressed in millimeters. Standard pressure is
approximately 760 mmHg.
RELATIVE AIR
PRESSURE
RELATIVE
BAROMETRIC
PRESSURE
Relative air pressure is the absolute air pressure
compensated for the altitude of the barometer. The
result is what the air pressure would be at sea level.
ULTRA VIOLET
INDEX
The ultraviolet index or UV-Index (UVI) is an
international standard measurement of the strength of
sunburn-producing ultraviolet (UV) radiation at a
particular place and time. The purpose of the UV
Index is to help people effectively protect themselves
from UV radiation. The UV Index is a linear scale,
with higher values representing a greater risk of
sunburn (which is correlated with other health risks)
due to UV exposure. An index of 0 corresponds to
zero UV radiation, as is essentially the case at night.
An index of 10 corresponds roughly to midday
