DAVIS 6322C - Manual (Page 18)

Locating the ISS and Anemometer
16
General ISS Siting Guidelines
• Place the ISS away from sources of heat such as chimneys, heaters, air conditioners
and exhaust vents.
• Place the ISS at least 100' (30 m) away from any asphalt or concrete roadway that
readily absorbs and radiates heat in the sun. Avoid installations near fences or
sides of buildings that receive a lot of sun during the day.
• Ideally, place the radiation shield of the ISS 5' (1.5 m) above the ground in the mid-
dle of gently sloping or flat, regularly mowed grassy or naturally landscaped area
that drains well when it rains. For areas with average maximum yearly snow
depths over 3' (0.9 m), mount the ISS 2' (0.6 m) above this depth.
• Never install the ISS where it will be directly sprayed by a sprinkler system
because it will adversely affect the readings.
• Avoid installations near bodies of water such as swimming pools or ponds.
• Do not locate the ISS under tree canopies or near the side of buildings that create
“rain shadows." For heavily forested areas, site the ISS in a clearing or meadow.
• Site the ISS in a location with good sun exposure throughout the day if the ISS is
wireless or includes solar radiation or UV radiation sensors.
For agricultural applications (important for evapotranspiration (ET) calculations):
• Install the ISS and anemometer as a single unit with the radiation shield 5'
(1.5 m) above the ground and in the middle of the farm between similar crop
types (i.e. two orchards, two vineyards or two row crops), if possible.
• Avoid areas exposed to extensive or frequent applications of agricultural chemi-
cals (which can degrade the sensors).
• Avoid installation over bare soil. The ET formula works best when the ISS is
installed over well-irrigated, regularly mowed grass.
• If the last three guidelines cannot be met, install the weather station at the edge
of the primary crop of interest.
Anemometer Siting Guidelines
• For best results, place the anemometer at least 7' (2.1 m) above surrounding
obstructions such as trees or buildings that obstruct wind flow.
• If mounting on a roof, mount the anemometer at least 7' (2.1 m) above the roof
apex (when using a Mounting Tripod, install the anemometer at the very top of the
pole).
• If mounting the ISS and the anemometer together, such as on a pole or a wooden
post, mount the anemometer so it is at least 12'' (0.3 m) above the top of the rain
collector cone for best results.
• The standard for meteorological and aviation applications is to place the anemom-
eter 33' (10 m) above the ground. Seek professional help for this type of installa-
tion.
• The standard for agricultural applications is to place the anemometer 6' (2 m) above
the ground. This is important for evapotranspiration (ET) calculations.
Note: For roof mounting, and ease of installation, we recommend using the optional mounting tripod
(#7716). For other installations, use the Mounting Pole Kit (#7717).
Note: For more detailed siting suggestions, see Application Note #30: Reporting Quality Observations to
NOAA on the Davis Support web site (http://www.davisnet.com/support/weather).