Standard measurement heights:
l
1.5 m ± 1.0 m (AASC)
l
1.25 to 2.00 m (WMO)
l
2.0 m temperature (EPA)
l
2.0 m and 10.0 m for temperature difference (EPA)
4.3 Precipitation
Rain gages must be sited on level ground covered with short grass or gravel. In open areas,
choose a site where the distance to any obstruction is two to four times (EPA, AASC) the height
of the obstruction.
Position the height of the opening as low as possible, but high enough to avoid splashing from
the ground. Wind shields, such as Campbell Scientific 260 953 Alter-Type Rain Gage Wind
Screen, are recommended for open areas.
When necessary, use heated collectors to properly measure frozen precipitation. The gage must
be mounted above the average level of snow accumulation in areas that experience significant
snowfall.
Standard measurement heights:
l
1.0 m ± 1.0 cm (AASC)
l
30.0 cm minimum (WMO, EPA)
4.4 Solar radiation
Mount pyranometers in locations that avoid shadows on the sensor at any time. Mounting the
sensor on the Southernmost (Northern Hemisphere) or Northernmost (Southern Hemisphere)
portion of the weather station will minimize the chance of shading from other weather station
structures. Reflective surfaces and sources of artificial radiation must be avoided.
Heated pyranometers, such as the SP230-L from Campbell Scientific, are available for use in areas
where snow, frost, or dew may accumulate.
The height the sensor is mounted is not critical.
4.5 Soil temperature
Prepare a site for soil temperature measurements at least one square meter and typical of the
surface of interest. The ground surface must be level to the immediate area (10 m radius).
UT6 and UT10 Universal Towers
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