DAVIS Health EnviroMonitor: Console - Manual (Page 48)

Weather Conditions Measured/Calculated
Health EnviroMonitor Manual Page 9
• “Daily” High and Low Inside Temperature with time of occurrence (AutoClear)
Wind
The Health EM measures and displays both wind speed and wind direction. In
general, wind speed and wind direction readings are visible at all times in the
compass rose on the left side of the display.
• Current Wind Speed (Alarm: High)
• Wind Direction (in compass rose only)
• High Wind Speed with direction of high and time of occurrence (AutoClear)
Solar Radiation
What we call “current solar radiation” is technically known as Global Solar
Radiation, a measure of the intensity of the sun’s radiation reaching the earth’s
surface. This irradiance includes both the direct component from the sun and
the diffuse component from the rest of the sky. The solar radiation reading
gives a measure of the amount of solar radiation hitting the solar radiation sen-
sor at any given time, expressed in Watts per Square Meter (W/m
2
).
• Current Solar Radiation Intensity
• “Daily” High Solar Radiation with time of occurrence
Barometric Pressure
The weight of the air which makes up our atmosphere exerts a pressure on the
surface of the earth. This pressure is known as atmospheric pressure. Gener-
ally, the more air above an area, the higher the atmospheric pressure, which
means that atmospheric pressure changes with altitude. To compensate for this
difference and facilitate comparison between locations with different altitudes,
atmospheric pressure is generally adjusted to the equivalent sea-level pressure.
This adjusted pressure is known as barometric pressure. In reality, the
Health EM measures atmospheric pressure. When you enter the barometric
pressure for your location (see “Entering Barometric Pressure” on page 32), the
Health EM stores the necessary offset value to consistently translate atmo-
spheric pressure into barometric pressure.
Barometric pressure also changes with local weather conditions, which makes
barometric pressure an extremely important and useful weather forecasting
tool. High pressure zones are associated with fair weather while low pressure
zones are associated with poor weather. For forecasting purposes, however, the
absolute barometric pressure value is generally less important than the change
in barometric pressure. In general, rising pressure indicates improving weather
conditions while falling pressure indicates deteriorating weather conditions.
• Current Barometric Pressure (Alarm: rate of change)
• Trend of Barometric Pressure (rising, falling, steady) over previous one hour