and NWS Observing Handbook No. 2 for details.)
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
Rooftop Temperature Bias