Specifications for Australian
meteorological stations
are set out in the BOM
Observation Specification:
2013.1
“GUIDELINES FOR THE SITING AND EXPOSURE OF METEOROLOGICAL INSTRUMENTS AND OBSERVING FACILITIES”.
3.4.1 “… the Instrument enclosure is a 17 metres by 17 metres square enclosure in the middle of a 30 metre by 30 metre square buffer zone aligned in the true North – South direction.”
3.4.2 The enclosure area is to be “level, clearly defined and covered with as much of the natural vegetation of the area that can kept cut to a height of a few centimetres… should not be artificially watered.”
Concrete or asphalt walkways no wider than 0.5 metres should be minimal and only installed if the ground will be impassable or unsafe in wet conditions.
3.4.3 The buffer zone must also be covered with natural vegetation maintained below 0.5 metres.
3.4.4 An isolated obstruction up to 15 metres high should be 4 times its height in distance from the enclosure.
3.6.4 “If a shelter is required at locations where no instrument enclosure is to be provided, it must be installed in an area that is level and covered with either the natural vegetation of the area or unwatered grass, which needs to be kept trimmed to a few centimetres in height.
The site should not be in a hollow or on a steep slope.
The shelter should be freely exposed to the sun and wind, and not shielded by or close to trees, buildings, fences, walls or other obstructions.
It should also not be close to extensive areas of concrete, asphalt, rock or other surfaces which may locally alter the air temperature of the site.
In areas where these surfaces are unavoidable, a minimum clearance of 5 times the width of the unrepresentative surface is recommended.”