Orion 420 Weather Station
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Columbia Weather Systems, Inc.
Global Radiation
The total of direct solar radiation and diffused sky radiation received by a
unit horizontal surface. Global radiation is measured by a pyranometer.
Heat Index
The heat index or apparent temperature is a measure of discomfort due
to the combination of heat and high humidity. It was developed in 1979
and is based on studies of evaporative skin cooling for combinations of
temperature and humidity.
Pyranometer
It measures the combined intensity of incoming direct solar radiation and
diffused sky radiation. The pyranometer consists of a radiation-sensing
element, which is mounted so that it views the entire sky.
Relative Humidity
Popularly called humidity. The ratio of the actual vapor pressure of the
air to the saturation vapor pressure.
Sea Level Pressure
The atmospheric pressure at mean sea level, either directly measured
or, most commonly, empirically determined from the observed station
pressure.
In regions where the earth’s surface pressure is above sea level, it is
standard observational practice to reduce the observed surface pressure
to the value that would exist at a point at sea level directly below.
Solar Radiation
The total electromagnetic radiation emitted by the sun. 99% of the sun’s
energy output falls within the wavelength interval from 0.15 microns to
4.0 microns, with peak intensity near 0.47 microns. About one-half of the
total energy in the solar beam is contained within the visible spectrum
from 0.4 to 0.7 microns, and most of the other half lies near infrared, a
small additional portion lying in the ultraviolet.
Wind Chill
That part of the total cooling of a body caused by air motion.
