Siting

The TempVue 20 is intended for air temperature measurements only. The general EPA guidance for standard meteorological stations is to locate the sensor over an open, level area at least 9 m (29.5 ft) in diameter. The surface should be covered by short grass or the natural earth where grass does not grow. Sensors should be protected from thermal radiation and adequately ventilated. Protect the filter at the top of the sensor from exposure to liquid water.

Clearances

The sensor should be installed at a standard measurement height, which varies depending on the guides being used:

  • 1.5 m (4.92 ft) (AASC)
  • 1.25 to 2.0 m (4.1 to 6.5 ft) (WMO)
  • 2.0 m (6.5 ft) (EPA)

See References for a list of references that discuss temperature sensors.

When used in the field, the TempVue 20 must be housed in a Closedradiation shield A housing that protects an air temperature sensor from solar radiation, precipitation, and wind while allowing air circulation around the sensing element. Required for accurate air temperature measurements with the TempVue 20 in outdoor installations.. Compatible radiation shields include the RAD06, RAD10E, and RAD14 unventilated radiation shields and the TS100SS fan-aspirated radiation shield. The white color of these shields reflects solar radiation.

The unventilated radiation shields have a louvered construction that allows air to pass freely though, thereby keeping the sensor at or near ambient temperature. The RAD06, RAD10E, and RAD14 have a double-louvered design that offers improved sensor protection from insect intrusion and driving rain and snow. In addition, compared to shields of a similar appearance, the RAD shields have lower self-heating in bright sunlight combined with low wind speeds giving a better measurement. The RAD shields attach to a crossarm, mast, or user-supplied pipe with a 2.5 to 5.3 cm (1.0 to 2.1 inch) outer diameter.

The Apogee Instruments aspirated TS100SS shield can also be used where minimal solar errors and a fast speed of response is desired. It mounts on a crossarm or horizontal pipe (1-1/4 inch to 2 inch IPS).

Tools required for installing a radiation shield to a tripod or tower include:

  • Adjustable wrench (to suit 12 mm (1/2 in) nuts)
  • Small screwdriver provided with data logger
  • Small Phillips screwdriver
  • UV-resistant cable ties
  • Small pair of diagonal-cutting pliers
  • Adjustable wrench with a minimum 50 mm (2 in) jaw size