Aercus Instruments™
- WeatherMaster
92 |
P a g e
TERM
DESCRIPTION
further cooled, the airborne water vapor will
condense to form liquid water (dew), or frost if
below freezing.
HEAT INDEX
The heat index (HI) or humiture is an index
that combines air temperature and relative
humidity, in shaded areas, as an attempt to
determine the human-perceived equivalent
temperature, as how hot it would feel if the
humidity were some other value in the shade.
Heat index only applies when the temperature
is above 27 degrees Celsius and the humidity is
above 40%.
HECTOPASCALS (hPa)
This is an international standard (SI system) for
measuring air pressure. It used to be referred
to as milli-bars (mb) and sometimes still is.
They are equivalent.
HYGROMETER
An instrument that measures relative humidity
of the air. This is expressed as a percentage
between 0% and 100%.
INCHES OF MERCURY
(inHg)
This imperial 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.
LUX (lx)
The unit of illuminance (a measure of the
intensity of illumination on a surface) as used
