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Proper Siting
The COOP network has provided climate and weather data for over
100 years. Consistency of the measurements is an attribute of
the network, and it has been maintained by rare and/or gradual
change, and established standards for exposure, of instruments
over the life of the network. In order to preserve the integrity
of the network, NWS has established
standards for equipment, siting, and exposure.
Temperature sensor siting: The sensor should be mounted
5 feet +/- 1 foot above the ground. The ground
over which the shelter [radiation] is located should be typical
of the surrounding area. A level, open clearing is desirable so
the thermometers are freely ventilated by air flow. Do not install
the sensor on a steep slope or in a sheltered hollow unless it
is typical of the area or unless data from that type of site are
desired. When possible, the shelter should be no closer than four
times the height of any obstruction (tree, fence, building, etc.).
The sensor should be at least 100 feet from any paved or concrete
surface.
Precipitation gauge siting: The exposure of a rain gauge
is very important for obtaining accurate measurements. Gauges
should not be located close to isolated obstructions such as trees
and buildings, which may deflect precipitation due to erratic
turbulence. To avoid wind and resulting turbulence problems,
do not locate gauges in wide-open spaces or on elevated sites,
such as the tops of buildings. The best site for a gauge
is one in which it is protected in all directions, such as in
an opening in a grove of trees. The height of the protection should
not exceed twice its distance from the gauge. As a general rule,
the windier the gauge location is, the greater the precipitation
error will be.
Rooftop Temperature
Bias Study
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