5.2 Temperature and relative humidity
Sensors should be located over an open, level area at least 9 m (29.5 ft) (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 (98.43 ft) (EPA) from large paved areas. Sensors should be
protected from thermal radiation and adequately ventilated.
Situations to avoid include:
l
large industrial heat sources
l
rooftops
l
steep slopes
l
sheltered hollows
l
high vegetation
l
shaded areas
l
swamps
l
areas where snow drifts occur
l
low places holding standing water after rains
5.3 Solar radiation
Pyranometers should be located to avoid shadows on the sensor at any time. Mounting it on the
southernmost (northern hemisphere) portion of the weather station will minimize the chance of
shading from other weather station structures. Reflective surfaces and sources of artificial
radiation should be avoided.
Section 5. Siting and exposure
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