Campbell UT10, Instruction Manual

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UT10 Universal Tower
4
Standard measurement heights:
3.0 m ± 0.1 m recommended (AASC)
2.0 m ± 0.1 m, 10.0 m ± 0.5 m optional (AASC)
10.0 m (WMO and EPA)
4.2 Temperature and Relative Humidity
Sensors should be located over an open level area at least 9 m (EPA) in
diameter. The surface should be covered by short grass, or where grass does
not grow, the natural earth surface. Sensors should be located at a distance of at
least four times the height of any nearby obstruction and at least 30 m (EPA)
from large paved areas. Sensors should be protected from thermal radiation,
and adequately ventilated.
Situations to avoid include:
•
large industrial heat sources
•
rooftops
•
steep slopes
•
sheltered hollows
•
high vegetation
•
shaded areas
•
swamps
•
areas where snow drifts occur
•
low places holding standing water after rains
Standard measurement heights:
1.5 m ± 1.0 m (AASC)
1.25 – 2.0 m (WMO)
2.0 m temperature (EPA)
2.0 m and 10.0 m for temperature difference (EPA)
4.3 Precipitation
A rain gage should be sited on level ground that is covered with short grass or
gravel. In open areas, the distance to obstructions should be two to four times
(EPA, AASC) the height of the obstruction.
The height of the opening should be as low as possible, but should be high
enough to avoid splashing from the ground. Wind shields, such as those used
by the National Weather Service, are recommended for open areas.
Collectors should be heated, if necessary, 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:
1.0 m ± 1.0 cm (AASC)
30.0 cm minimum (WMO, EPA)