Aercus Instruments™
- WeatherMaster
75 |
P a g e
(1)
Temperature errors can occur when a sensor is placed too
close to a heat source (such as a building structure, the
ground or trees).
To calibrate temperature, we recommend a mercury or red
spirit (fluid) thermometer. Bi-metal (dial) and digital
thermometers (from other weather stations) are not a good
source and have their own margin of error. Using a local
weather station in your area is also a poor source due to
changes in location, timing (airport weather stations are only
updated once per hour) and possible calibration errors.
Place the sensor in a shaded, controlled environment next to
the fluid thermometer, and allow the sensor to stabilise for
48 hours. Compare this temperature to the fluid
thermometer and adjust the console to match the fluid
thermometer.
(2)
Humidity is a difficult parameter to measure electronically and
drifts over time due to contamination. In addition, location
has an adverse effect on humidity readings (installation over
dirt or lawn for example).
Official stations recalibrate or replace humidity sensors on a
yearly basis. Due to manufacturing tolerances, the humidity is
accurate to ± 5%. To improve this accuracy, the indoor and
outdoor humidity can be calibrated using an accurate source,
such as a sling psychrometer.
(3)
The display console displays two different pressures: absolute
(measured) and relative (corrected to sea-level).
To compare pressure conditions from one location to another,
meteorologists correct pressure to sea-level conditions. Because the
air pressure decreases as you rise in altitude, the sea-level corrected
pressure (the pressure your location would be at if located at
sea-level) is generally higher than your measured pressure.
