TAIR

Air Temperature (1.5 m)

The 5-minute average air temperature at a height of 1.5 meters above the ground.

  • This sensor is quite rugged and accurate. Prior to 2009, the sensor was housed in a naturally-ventilated radiation shield. Such shields can create temperature errors of several degrees Celsius when the wind is calm (less than 1 m/sec) and solar radiation is high.
  • Since 2009, the sensor is housed in an aspirated radiation shield, which continuously draws ambient air over the sensor, while protecting it from solar radiation.
Type Sensor Used Standards Units Accuracy
Standard - Primary Thermometrics Air Temperature 2004-Present; PDF Vaisala HMP35C 1994-2003 degrees Celsius ± 0.5 °C

Thermometrics Air Temperature Sensor

TA9M

Air Temperature (9 m)

Same sensor as TAIR but positioned at 9 meters above ground level.

  • This thermistor uses an unaspirated radiation shield, resulting in readings with a warm bias on calm, sunny days.
Type Sensor Used Standards Units Accuracy
Standard - Secondary Thermometrics Air Temperature, PDF degrees Celsius ± 0.5 °C when windspeed is > 6 m/s
      ± 1.0 °C when windspeed is 3 - 6 m/s
      ± 1.5 °C when windspeed is 2 - 3 m/s
      ±3.0°C when windspeed is 1 - 2 m/s

Thermometrics Air Temperature Sensor

HEAT

Heat Index

Not measured, but computed from the 1.5 meter air temperature and relative humidity.

  • The heat index is used to provide information about possible heat stress on the human body.
Sensor Used Standard Units
Thermometrics Air Temperature (for Air Temperature), PDF degrees Celsius
Vaisala HMP45C (for Relative Humidity), PDF

Vaisala HMP45C Sensor

Thermometrics Air Temperature Sensor

CHIL

Wind Chill

Not measured, but computed from the 1.5 meter air temperature and the wind speed at 10 meters.

  • Wind chill represents the cooling effect on the human body of low temperatures combined with wind.
Sensor Used Standard Units
Thermometrics Air Temperature (for Air Temperature), PDF degrees Celsius
RM Young Wind Monitor (for Wind Speed), PDF  

RM Young Wind Monitor Sensor

Thermometrics Air Temperature Sensor