Altimeter settings updated each minute
An Hourly Surface Aviation Weather
Observation report
Daily weather summary to monitor or printer
Monthly weather summary to monitor or printer
Sensor Package
One or more ASOS sensor packages (fig. 2-1) are
normally located at the touch-down end of main
runways.
From left to right, figure 2-1 shows the
following sensors:
Visibility sensor-Reports equivalent visibility
in l/4-statute-mile increments up to 10 statute miles
Present weather sensor-Uses an infrared beam
to sense precipitation, and reports light, moderate, and
heavy rain, snow, or mixed precipitation
Wind direction and wind speed-Measures
speed, in knots, from 0 to 125 knots
Data collection package (equipment
case)-Sends semiprocessed data to the acquisition
control unit in the weather office
Temperature and dew-point sensor-Measures
temperature from -80°F to 130°F and dew-point from -
30°F to 86°F to the nearest tenth of a degree, and also
computes relative humidity
Heated tipping-bucket rain gauge-Measures
precipitation rate from 0 to 10.0 inches per hour, in
hundredths of an inch
Cloud height sensor-A laser detector that
reports cloud bases from 100 feet above ground level
(AGL) to 12,000 feet AGL
A digital pressure transducer that measures
atmospheric pressure from 16.90 inches to 31.50
Figure 2-1.—ASOS sensors: A. Visibility sensor; B. present weather sensor; C. wind direction and wind speed sensor; D. freezing rain
sensor; E. DCP antenna and data collection package (equipment case); F. temperature and dew-point sensors; G. rain gauge; and
H. cloud height sensor.
2-2
